Home |
Search |
Today's Posts |
#1
|
|||
|
|||
Amp Catastrophies
Hi Group,
After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day |
#2
|
|||
|
|||
Amp Catastrophies
Hey JVC,
We all do them. I was troubleshooting the middle board of a 3-tier wire-wrap board-based unit back in the 80s. These boards were full of digital ICs and we had an 80-amp power supply for the box. I rested my hand on the top board as I was doing some probing when my watch got quite warm! (Thanks for the series resistance of it!). I am also reminded of college (DeVry) when the whole class had to build a power supply. The last couple of weeks in the lab when everyone was completing their construction and powering it on for the first time yielded several explosions as the caps that were installed backwards blew. --RY "JVC" writes: Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day -- % Randy Yates % "Midnight, on the water... %% Fuquay-Varina, NC % I saw... the ocean's daughter." %%% 919-577-9882 % 'Can't Get It Out Of My Head' %%%% % *El Dorado*, Electric Light Orchestra http://home.earthlink.net/~yatescr |
#3
|
|||
|
|||
Amp Catastrophies
Hey JVC,
We all do them. I was troubleshooting the middle board of a 3-tier wire-wrap board-based unit back in the 80s. These boards were full of digital ICs and we had an 80-amp power supply for the box. I rested my hand on the top board as I was doing some probing when my watch got quite warm! (Thanks for the series resistance of it!). I am also reminded of college (DeVry) when the whole class had to build a power supply. The last couple of weeks in the lab when everyone was completing their construction and powering it on for the first time yielded several explosions as the caps that were installed backwards blew. --RY "JVC" writes: Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day -- % Randy Yates % "Midnight, on the water... %% Fuquay-Varina, NC % I saw... the ocean's daughter." %%% 919-577-9882 % 'Can't Get It Out Of My Head' %%%% % *El Dorado*, Electric Light Orchestra http://home.earthlink.net/~yatescr |
#4
|
|||
|
|||
Amp Catastrophies
Hey JVC,
We all do them. I was troubleshooting the middle board of a 3-tier wire-wrap board-based unit back in the 80s. These boards were full of digital ICs and we had an 80-amp power supply for the box. I rested my hand on the top board as I was doing some probing when my watch got quite warm! (Thanks for the series resistance of it!). I am also reminded of college (DeVry) when the whole class had to build a power supply. The last couple of weeks in the lab when everyone was completing their construction and powering it on for the first time yielded several explosions as the caps that were installed backwards blew. --RY "JVC" writes: Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day -- % Randy Yates % "Midnight, on the water... %% Fuquay-Varina, NC % I saw... the ocean's daughter." %%% 919-577-9882 % 'Can't Get It Out Of My Head' %%%% % *El Dorado*, Electric Light Orchestra http://home.earthlink.net/~yatescr |
#5
|
|||
|
|||
Amp Catastrophies
Hey JVC,
We all do them. I was troubleshooting the middle board of a 3-tier wire-wrap board-based unit back in the 80s. These boards were full of digital ICs and we had an 80-amp power supply for the box. I rested my hand on the top board as I was doing some probing when my watch got quite warm! (Thanks for the series resistance of it!). I am also reminded of college (DeVry) when the whole class had to build a power supply. The last couple of weeks in the lab when everyone was completing their construction and powering it on for the first time yielded several explosions as the caps that were installed backwards blew. --RY "JVC" writes: Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day -- % Randy Yates % "Midnight, on the water... %% Fuquay-Varina, NC % I saw... the ocean's daughter." %%% 919-577-9882 % 'Can't Get It Out Of My Head' %%%% % *El Dorado*, Electric Light Orchestra http://home.earthlink.net/~yatescr |
#6
|
|||
|
|||
Amp Catastrophies
Not audio but it is electronics.
In High School, Physics, we set about building an RC plane and the Electronics (Heathkit) as an overal examination of flight, aircraft construction, radio Transmission, servo control, etc... In our class was a chap we called Tiny (He was quite all) We should have called him Twitchy. Tiny had a twitch, every once in a while, his whole body would twitch and whatever he was working on would gte messed up, usually quite badly. Fro some odd reason, the teacher gave Tiny the job of assembling the Servo Motor Control boards, which were quite small and required a good degree of precision to solder properly. Well the end of the year arrived and we had 4 dead Servo's and 1 partially operational Servo and an RC plane that never flew, due to lack of control electronics. The damage to the servo boards was so severe, that Heathkit even refused to consider replacing them at all. On another occasion, Tiny brought a Tube Amp in to class to attempt repair. Probbaly just a bad tube, but after hooking up an Audio Oscillator a load and an Oscilloscope, one Twitch and that was the end of the Amp, blown caps, Scope and Oscillator. I heard years later that Tiny went on to work in the Train industry, so I don't know how many engines he ruined, or maybe they were not as severly affected by his twitch. At my first employ, fresh from DeVry, I was set to work alongside another person for training. We were working at GTE, in 1976 and it was a waterfall experience. The year I started there, the telephony industry was going through a major upheavel. At that time, almost all CO (Central Office) gear was electromechanical for all the major communication pathways. We built large PCB (Printed Circuit Boards) with 20 and upwards of 40 multicontact relays on each. This was just past the build of the last Strowger Two Motion Switch. Anyhow, this guy is showing me how to remove a defective relay from a PCB and he carefully unsolders all the pins, wiggles them all to break the solder connection and then turnes the PCB over to pull the relay. It didn't want to come out of the board, so he pops the plastic cover off the relay and then places a large screwdriver under the relay and with much physical work and loud grunting, he removes a relay from the PCB, trailing a collection of PCB traces stil soldered to all it's pins. Obviously, he had puled the wrong relay. I was amazed at the mans strength though. My most recent experience is mechanical. I acquired a Realistic DX-160 shortwave and in the course of cleaning it up, I decided to remove all the control knobs. Well, the former owner had used glue to secure the knobs on the shafts. I roke a shaft right off trying to pull the knob, the brass broke, before the plastic knob gave out. I fashioned a tube with some thin brass folil and applied heat and solder to the parts and reattached the broken pieces. It's not perfect, but it works. I suppose I shoul dhave realized something was amiss and looked for a different solution, rather than force to remove the knob. rtt |
#7
|
|||
|
|||
Amp Catastrophies
Not audio but it is electronics.
In High School, Physics, we set about building an RC plane and the Electronics (Heathkit) as an overal examination of flight, aircraft construction, radio Transmission, servo control, etc... In our class was a chap we called Tiny (He was quite all) We should have called him Twitchy. Tiny had a twitch, every once in a while, his whole body would twitch and whatever he was working on would gte messed up, usually quite badly. Fro some odd reason, the teacher gave Tiny the job of assembling the Servo Motor Control boards, which were quite small and required a good degree of precision to solder properly. Well the end of the year arrived and we had 4 dead Servo's and 1 partially operational Servo and an RC plane that never flew, due to lack of control electronics. The damage to the servo boards was so severe, that Heathkit even refused to consider replacing them at all. On another occasion, Tiny brought a Tube Amp in to class to attempt repair. Probbaly just a bad tube, but after hooking up an Audio Oscillator a load and an Oscilloscope, one Twitch and that was the end of the Amp, blown caps, Scope and Oscillator. I heard years later that Tiny went on to work in the Train industry, so I don't know how many engines he ruined, or maybe they were not as severly affected by his twitch. At my first employ, fresh from DeVry, I was set to work alongside another person for training. We were working at GTE, in 1976 and it was a waterfall experience. The year I started there, the telephony industry was going through a major upheavel. At that time, almost all CO (Central Office) gear was electromechanical for all the major communication pathways. We built large PCB (Printed Circuit Boards) with 20 and upwards of 40 multicontact relays on each. This was just past the build of the last Strowger Two Motion Switch. Anyhow, this guy is showing me how to remove a defective relay from a PCB and he carefully unsolders all the pins, wiggles them all to break the solder connection and then turnes the PCB over to pull the relay. It didn't want to come out of the board, so he pops the plastic cover off the relay and then places a large screwdriver under the relay and with much physical work and loud grunting, he removes a relay from the PCB, trailing a collection of PCB traces stil soldered to all it's pins. Obviously, he had puled the wrong relay. I was amazed at the mans strength though. My most recent experience is mechanical. I acquired a Realistic DX-160 shortwave and in the course of cleaning it up, I decided to remove all the control knobs. Well, the former owner had used glue to secure the knobs on the shafts. I roke a shaft right off trying to pull the knob, the brass broke, before the plastic knob gave out. I fashioned a tube with some thin brass folil and applied heat and solder to the parts and reattached the broken pieces. It's not perfect, but it works. I suppose I shoul dhave realized something was amiss and looked for a different solution, rather than force to remove the knob. rtt |
#8
|
|||
|
|||
Amp Catastrophies
Not audio but it is electronics.
In High School, Physics, we set about building an RC plane and the Electronics (Heathkit) as an overal examination of flight, aircraft construction, radio Transmission, servo control, etc... In our class was a chap we called Tiny (He was quite all) We should have called him Twitchy. Tiny had a twitch, every once in a while, his whole body would twitch and whatever he was working on would gte messed up, usually quite badly. Fro some odd reason, the teacher gave Tiny the job of assembling the Servo Motor Control boards, which were quite small and required a good degree of precision to solder properly. Well the end of the year arrived and we had 4 dead Servo's and 1 partially operational Servo and an RC plane that never flew, due to lack of control electronics. The damage to the servo boards was so severe, that Heathkit even refused to consider replacing them at all. On another occasion, Tiny brought a Tube Amp in to class to attempt repair. Probbaly just a bad tube, but after hooking up an Audio Oscillator a load and an Oscilloscope, one Twitch and that was the end of the Amp, blown caps, Scope and Oscillator. I heard years later that Tiny went on to work in the Train industry, so I don't know how many engines he ruined, or maybe they were not as severly affected by his twitch. At my first employ, fresh from DeVry, I was set to work alongside another person for training. We were working at GTE, in 1976 and it was a waterfall experience. The year I started there, the telephony industry was going through a major upheavel. At that time, almost all CO (Central Office) gear was electromechanical for all the major communication pathways. We built large PCB (Printed Circuit Boards) with 20 and upwards of 40 multicontact relays on each. This was just past the build of the last Strowger Two Motion Switch. Anyhow, this guy is showing me how to remove a defective relay from a PCB and he carefully unsolders all the pins, wiggles them all to break the solder connection and then turnes the PCB over to pull the relay. It didn't want to come out of the board, so he pops the plastic cover off the relay and then places a large screwdriver under the relay and with much physical work and loud grunting, he removes a relay from the PCB, trailing a collection of PCB traces stil soldered to all it's pins. Obviously, he had puled the wrong relay. I was amazed at the mans strength though. My most recent experience is mechanical. I acquired a Realistic DX-160 shortwave and in the course of cleaning it up, I decided to remove all the control knobs. Well, the former owner had used glue to secure the knobs on the shafts. I roke a shaft right off trying to pull the knob, the brass broke, before the plastic knob gave out. I fashioned a tube with some thin brass folil and applied heat and solder to the parts and reattached the broken pieces. It's not perfect, but it works. I suppose I shoul dhave realized something was amiss and looked for a different solution, rather than force to remove the knob. rtt |
#9
|
|||
|
|||
Amp Catastrophies
Not audio but it is electronics.
In High School, Physics, we set about building an RC plane and the Electronics (Heathkit) as an overal examination of flight, aircraft construction, radio Transmission, servo control, etc... In our class was a chap we called Tiny (He was quite all) We should have called him Twitchy. Tiny had a twitch, every once in a while, his whole body would twitch and whatever he was working on would gte messed up, usually quite badly. Fro some odd reason, the teacher gave Tiny the job of assembling the Servo Motor Control boards, which were quite small and required a good degree of precision to solder properly. Well the end of the year arrived and we had 4 dead Servo's and 1 partially operational Servo and an RC plane that never flew, due to lack of control electronics. The damage to the servo boards was so severe, that Heathkit even refused to consider replacing them at all. On another occasion, Tiny brought a Tube Amp in to class to attempt repair. Probbaly just a bad tube, but after hooking up an Audio Oscillator a load and an Oscilloscope, one Twitch and that was the end of the Amp, blown caps, Scope and Oscillator. I heard years later that Tiny went on to work in the Train industry, so I don't know how many engines he ruined, or maybe they were not as severly affected by his twitch. At my first employ, fresh from DeVry, I was set to work alongside another person for training. We were working at GTE, in 1976 and it was a waterfall experience. The year I started there, the telephony industry was going through a major upheavel. At that time, almost all CO (Central Office) gear was electromechanical for all the major communication pathways. We built large PCB (Printed Circuit Boards) with 20 and upwards of 40 multicontact relays on each. This was just past the build of the last Strowger Two Motion Switch. Anyhow, this guy is showing me how to remove a defective relay from a PCB and he carefully unsolders all the pins, wiggles them all to break the solder connection and then turnes the PCB over to pull the relay. It didn't want to come out of the board, so he pops the plastic cover off the relay and then places a large screwdriver under the relay and with much physical work and loud grunting, he removes a relay from the PCB, trailing a collection of PCB traces stil soldered to all it's pins. Obviously, he had puled the wrong relay. I was amazed at the mans strength though. My most recent experience is mechanical. I acquired a Realistic DX-160 shortwave and in the course of cleaning it up, I decided to remove all the control knobs. Well, the former owner had used glue to secure the knobs on the shafts. I roke a shaft right off trying to pull the knob, the brass broke, before the plastic knob gave out. I fashioned a tube with some thin brass folil and applied heat and solder to the parts and reattached the broken pieces. It's not perfect, but it works. I suppose I shoul dhave realized something was amiss and looked for a different solution, rather than force to remove the knob. rtt |
#10
|
|||
|
|||
Amp Catastrophies
In article ,
"JVC" wrote: Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. |
#11
|
|||
|
|||
Amp Catastrophies
In article ,
"JVC" wrote: Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. |
#12
|
|||
|
|||
Amp Catastrophies
In article ,
"JVC" wrote: Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. |
#13
|
|||
|
|||
Amp Catastrophies
In article ,
"JVC" wrote: Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. |
#14
|
|||
|
|||
Amp Catastrophies
"JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day In the late '70s, I worked as a contract engineer for a number of broadcast stations. One night I was doing transmitter maintenance on a 100-kilowatt FM station in a large transmitter complex at the top of a ski area near Boise ID. It was about 3:00AM, and I had just finished replacing the main power amplifier tube, and a bunch of other general maintenance. Working on high-power transmitters is always cause for a bit of nervousness, and this particular transmitter was more glitchy than others I've worked on. Anyway, I got everything finished, so I secured the doors on the refrigerator-sized cabinet, powered it up, and started tuning it up. I just about had it back up to full power when -- BANG!! -- it sounded like a shotgun going off inside the transmitter as it immediately dropped off the air. I had a mental picture of some critical, expensive, hard-to-get high-voltage component completely fried, and my client off the air for a week while we wait for parts. I powered the whole thing down, and went around back and cautiously opened the cabinet to survey the damage. The 3/4-horse cooling fan was still coasting to a stop. Inside, the air was filled with some kind of fuzz or something. What the...??? I couldn't think of any component that would throw fuzz everywhere when it exploded. Then my eye fell on an insulated stand-off mounted on the floor of the cabinet, where the main high-voltage power supply lines entered the box. There, I saw the skeleton of a mouse, with its back feet on the metal cabinet floor, and it's nose about a centimeter from the high-voltage terminal. His last act must have been a curious sniff of the 10KV power supply line. I probably wouldn't have noticed him climb in there. Anyway, I gently lifted the bone-dry skeleton out of the cabinet and restarted the transmitter, which ran just fine. So it wasn't a catastrophe for me, but the mouse probably had a different perspective, if he ever got a chance to think about it. It also explained a few other dry mouse skeletons I found in the building when I first started working there. |
#15
|
|||
|
|||
Amp Catastrophies
"JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day In the late '70s, I worked as a contract engineer for a number of broadcast stations. One night I was doing transmitter maintenance on a 100-kilowatt FM station in a large transmitter complex at the top of a ski area near Boise ID. It was about 3:00AM, and I had just finished replacing the main power amplifier tube, and a bunch of other general maintenance. Working on high-power transmitters is always cause for a bit of nervousness, and this particular transmitter was more glitchy than others I've worked on. Anyway, I got everything finished, so I secured the doors on the refrigerator-sized cabinet, powered it up, and started tuning it up. I just about had it back up to full power when -- BANG!! -- it sounded like a shotgun going off inside the transmitter as it immediately dropped off the air. I had a mental picture of some critical, expensive, hard-to-get high-voltage component completely fried, and my client off the air for a week while we wait for parts. I powered the whole thing down, and went around back and cautiously opened the cabinet to survey the damage. The 3/4-horse cooling fan was still coasting to a stop. Inside, the air was filled with some kind of fuzz or something. What the...??? I couldn't think of any component that would throw fuzz everywhere when it exploded. Then my eye fell on an insulated stand-off mounted on the floor of the cabinet, where the main high-voltage power supply lines entered the box. There, I saw the skeleton of a mouse, with its back feet on the metal cabinet floor, and it's nose about a centimeter from the high-voltage terminal. His last act must have been a curious sniff of the 10KV power supply line. I probably wouldn't have noticed him climb in there. Anyway, I gently lifted the bone-dry skeleton out of the cabinet and restarted the transmitter, which ran just fine. So it wasn't a catastrophe for me, but the mouse probably had a different perspective, if he ever got a chance to think about it. It also explained a few other dry mouse skeletons I found in the building when I first started working there. |
#16
|
|||
|
|||
Amp Catastrophies
"JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day In the late '70s, I worked as a contract engineer for a number of broadcast stations. One night I was doing transmitter maintenance on a 100-kilowatt FM station in a large transmitter complex at the top of a ski area near Boise ID. It was about 3:00AM, and I had just finished replacing the main power amplifier tube, and a bunch of other general maintenance. Working on high-power transmitters is always cause for a bit of nervousness, and this particular transmitter was more glitchy than others I've worked on. Anyway, I got everything finished, so I secured the doors on the refrigerator-sized cabinet, powered it up, and started tuning it up. I just about had it back up to full power when -- BANG!! -- it sounded like a shotgun going off inside the transmitter as it immediately dropped off the air. I had a mental picture of some critical, expensive, hard-to-get high-voltage component completely fried, and my client off the air for a week while we wait for parts. I powered the whole thing down, and went around back and cautiously opened the cabinet to survey the damage. The 3/4-horse cooling fan was still coasting to a stop. Inside, the air was filled with some kind of fuzz or something. What the...??? I couldn't think of any component that would throw fuzz everywhere when it exploded. Then my eye fell on an insulated stand-off mounted on the floor of the cabinet, where the main high-voltage power supply lines entered the box. There, I saw the skeleton of a mouse, with its back feet on the metal cabinet floor, and it's nose about a centimeter from the high-voltage terminal. His last act must have been a curious sniff of the 10KV power supply line. I probably wouldn't have noticed him climb in there. Anyway, I gently lifted the bone-dry skeleton out of the cabinet and restarted the transmitter, which ran just fine. So it wasn't a catastrophe for me, but the mouse probably had a different perspective, if he ever got a chance to think about it. It also explained a few other dry mouse skeletons I found in the building when I first started working there. |
#17
|
|||
|
|||
Amp Catastrophies
"JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day In the late '70s, I worked as a contract engineer for a number of broadcast stations. One night I was doing transmitter maintenance on a 100-kilowatt FM station in a large transmitter complex at the top of a ski area near Boise ID. It was about 3:00AM, and I had just finished replacing the main power amplifier tube, and a bunch of other general maintenance. Working on high-power transmitters is always cause for a bit of nervousness, and this particular transmitter was more glitchy than others I've worked on. Anyway, I got everything finished, so I secured the doors on the refrigerator-sized cabinet, powered it up, and started tuning it up. I just about had it back up to full power when -- BANG!! -- it sounded like a shotgun going off inside the transmitter as it immediately dropped off the air. I had a mental picture of some critical, expensive, hard-to-get high-voltage component completely fried, and my client off the air for a week while we wait for parts. I powered the whole thing down, and went around back and cautiously opened the cabinet to survey the damage. The 3/4-horse cooling fan was still coasting to a stop. Inside, the air was filled with some kind of fuzz or something. What the...??? I couldn't think of any component that would throw fuzz everywhere when it exploded. Then my eye fell on an insulated stand-off mounted on the floor of the cabinet, where the main high-voltage power supply lines entered the box. There, I saw the skeleton of a mouse, with its back feet on the metal cabinet floor, and it's nose about a centimeter from the high-voltage terminal. His last act must have been a curious sniff of the 10KV power supply line. I probably wouldn't have noticed him climb in there. Anyway, I gently lifted the bone-dry skeleton out of the cabinet and restarted the transmitter, which ran just fine. So it wasn't a catastrophe for me, but the mouse probably had a different perspective, if he ever got a chance to think about it. It also explained a few other dry mouse skeletons I found in the building when I first started working there. |
#18
|
|||
|
|||
Amp Catastrophies
Kevin McMurtrie wrote:
Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. I spent a summer before grad school working on a prototype electric-powered delivery truck. It was powered by over a dozen of the largest golf cart batteries anybody made at the time. There were three battery boxes, each of which weighed something like a ton. The battteries in each box were connected in series so there was about 80 volts across each string. In paralell and fresh, they could deliver over 1,000 amps into a 72 volt DC motor via a SCR controller, for something like a minute. The contacts were at one end of the box, and to my chagrin I found that it was possible to short them out. They were hooked in series for charging with a transformerless battery charger operating off of a 240 volt three-phase power line. I had this little accident where I dropped a screw driver with a foot-long blade that could have doubled for a small crowbar. In one blue flash the screwdriver lost about half its length, and I was covered with many spatters of steel and copper. The good news is that I had safety glasses on and had turned away before actual contact was made. So, I was neither blinded nor did I need to visit a hospital. My tempered glass safety glasses had spatters of copper and steel melted into them to the extent that they had to be replaced. My face and forearms had little b-b sized chunks of copper and steel seared into them. But, in a week or two they mostly all fell out on their own. My clothes were perferated and had to be scrapped. The lesson was that batteries generally don't have effective power-off switches on them. |
#19
|
|||
|
|||
Amp Catastrophies
Kevin McMurtrie wrote:
Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. I spent a summer before grad school working on a prototype electric-powered delivery truck. It was powered by over a dozen of the largest golf cart batteries anybody made at the time. There were three battery boxes, each of which weighed something like a ton. The battteries in each box were connected in series so there was about 80 volts across each string. In paralell and fresh, they could deliver over 1,000 amps into a 72 volt DC motor via a SCR controller, for something like a minute. The contacts were at one end of the box, and to my chagrin I found that it was possible to short them out. They were hooked in series for charging with a transformerless battery charger operating off of a 240 volt three-phase power line. I had this little accident where I dropped a screw driver with a foot-long blade that could have doubled for a small crowbar. In one blue flash the screwdriver lost about half its length, and I was covered with many spatters of steel and copper. The good news is that I had safety glasses on and had turned away before actual contact was made. So, I was neither blinded nor did I need to visit a hospital. My tempered glass safety glasses had spatters of copper and steel melted into them to the extent that they had to be replaced. My face and forearms had little b-b sized chunks of copper and steel seared into them. But, in a week or two they mostly all fell out on their own. My clothes were perferated and had to be scrapped. The lesson was that batteries generally don't have effective power-off switches on them. |
#20
|
|||
|
|||
Amp Catastrophies
Kevin McMurtrie wrote:
Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. I spent a summer before grad school working on a prototype electric-powered delivery truck. It was powered by over a dozen of the largest golf cart batteries anybody made at the time. There were three battery boxes, each of which weighed something like a ton. The battteries in each box were connected in series so there was about 80 volts across each string. In paralell and fresh, they could deliver over 1,000 amps into a 72 volt DC motor via a SCR controller, for something like a minute. The contacts were at one end of the box, and to my chagrin I found that it was possible to short them out. They were hooked in series for charging with a transformerless battery charger operating off of a 240 volt three-phase power line. I had this little accident where I dropped a screw driver with a foot-long blade that could have doubled for a small crowbar. In one blue flash the screwdriver lost about half its length, and I was covered with many spatters of steel and copper. The good news is that I had safety glasses on and had turned away before actual contact was made. So, I was neither blinded nor did I need to visit a hospital. My tempered glass safety glasses had spatters of copper and steel melted into them to the extent that they had to be replaced. My face and forearms had little b-b sized chunks of copper and steel seared into them. But, in a week or two they mostly all fell out on their own. My clothes were perferated and had to be scrapped. The lesson was that batteries generally don't have effective power-off switches on them. |
#21
|
|||
|
|||
Amp Catastrophies
Kevin McMurtrie wrote:
Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. I spent a summer before grad school working on a prototype electric-powered delivery truck. It was powered by over a dozen of the largest golf cart batteries anybody made at the time. There were three battery boxes, each of which weighed something like a ton. The battteries in each box were connected in series so there was about 80 volts across each string. In paralell and fresh, they could deliver over 1,000 amps into a 72 volt DC motor via a SCR controller, for something like a minute. The contacts were at one end of the box, and to my chagrin I found that it was possible to short them out. They were hooked in series for charging with a transformerless battery charger operating off of a 240 volt three-phase power line. I had this little accident where I dropped a screw driver with a foot-long blade that could have doubled for a small crowbar. In one blue flash the screwdriver lost about half its length, and I was covered with many spatters of steel and copper. The good news is that I had safety glasses on and had turned away before actual contact was made. So, I was neither blinded nor did I need to visit a hospital. My tempered glass safety glasses had spatters of copper and steel melted into them to the extent that they had to be replaced. My face and forearms had little b-b sized chunks of copper and steel seared into them. But, in a week or two they mostly all fell out on their own. My clothes were perferated and had to be scrapped. The lesson was that batteries generally don't have effective power-off switches on them. |
#22
|
|||
|
|||
Amp Catastrophies
"Karl Uppiano" wrote in message ... "JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day In the late '70s, I worked as a contract engineer for a number of broadcast stations. One night I was doing transmitter maintenance on a 100-kilowatt FM station in a large transmitter complex at the top of a ski area near Boise ID. It was about 3:00AM, and I had just finished replacing the main power amplifier tube, and a bunch of other general maintenance. Working on high-power transmitters is always cause for a bit of nervousness, and this particular transmitter was more glitchy than others I've worked on. Anyway, I got everything finished, so I secured the doors on the refrigerator-sized cabinet, powered it up, and started tuning it up. I just about had it back up to full power when -- BANG!! -- it sounded like a shotgun going off inside the transmitter as it immediately dropped off the air. I had a mental picture of some critical, expensive, hard-to-get high-voltage component completely fried, and my client off the air for a week while we wait for parts. I powered the whole thing down, and went around back and cautiously opened the cabinet to survey the damage. The 3/4-horse cooling fan was still coasting to a stop. Inside, the air was filled with some kind of fuzz or something. What the...??? I couldn't think of any component that would throw fuzz everywhere when it exploded. Then my eye fell on an insulated stand-off mounted on the floor of the cabinet, where the main high-voltage power supply lines entered the box. There, I saw the skeleton of a mouse, with its back feet on the metal cabinet floor, and it's nose about a centimeter from the high-voltage terminal. His last act must have been a curious sniff of the 10KV power supply line. I probably wouldn't have noticed him climb in there. Anyway, I gently lifted the bone-dry skeleton out of the cabinet and restarted the transmitter, which ran just fine. So it wasn't a catastrophe for me, but the mouse probably had a different perspective, if he ever got a chance to think about it. It also explained a few other dry mouse skeletons I found in the building when I first started working there. I could describe one incident possibly a 'cat'astrophe. Many many years ago I joined a general cargo ship of the Brocklebank line as radio officer. The first time I threw the main switch to the HF transmitter there was a loud piercing shriek followed by a black blur, I shut it off immediately and investigated...couldn't find anything wrong. Sometime later I found out that the ships cat had a habit of getting into the rear of the unit while the ship was in port and making itself comfortable next to the power unit drying heaters (Early marine equipment used drying heaters to avoid condensation). Needless to say the cat never went near again..though I got into the habit of tapping the front panel before powering up - just in case. |
#23
|
|||
|
|||
Amp Catastrophies
"Karl Uppiano" wrote in message ... "JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day In the late '70s, I worked as a contract engineer for a number of broadcast stations. One night I was doing transmitter maintenance on a 100-kilowatt FM station in a large transmitter complex at the top of a ski area near Boise ID. It was about 3:00AM, and I had just finished replacing the main power amplifier tube, and a bunch of other general maintenance. Working on high-power transmitters is always cause for a bit of nervousness, and this particular transmitter was more glitchy than others I've worked on. Anyway, I got everything finished, so I secured the doors on the refrigerator-sized cabinet, powered it up, and started tuning it up. I just about had it back up to full power when -- BANG!! -- it sounded like a shotgun going off inside the transmitter as it immediately dropped off the air. I had a mental picture of some critical, expensive, hard-to-get high-voltage component completely fried, and my client off the air for a week while we wait for parts. I powered the whole thing down, and went around back and cautiously opened the cabinet to survey the damage. The 3/4-horse cooling fan was still coasting to a stop. Inside, the air was filled with some kind of fuzz or something. What the...??? I couldn't think of any component that would throw fuzz everywhere when it exploded. Then my eye fell on an insulated stand-off mounted on the floor of the cabinet, where the main high-voltage power supply lines entered the box. There, I saw the skeleton of a mouse, with its back feet on the metal cabinet floor, and it's nose about a centimeter from the high-voltage terminal. His last act must have been a curious sniff of the 10KV power supply line. I probably wouldn't have noticed him climb in there. Anyway, I gently lifted the bone-dry skeleton out of the cabinet and restarted the transmitter, which ran just fine. So it wasn't a catastrophe for me, but the mouse probably had a different perspective, if he ever got a chance to think about it. It also explained a few other dry mouse skeletons I found in the building when I first started working there. I could describe one incident possibly a 'cat'astrophe. Many many years ago I joined a general cargo ship of the Brocklebank line as radio officer. The first time I threw the main switch to the HF transmitter there was a loud piercing shriek followed by a black blur, I shut it off immediately and investigated...couldn't find anything wrong. Sometime later I found out that the ships cat had a habit of getting into the rear of the unit while the ship was in port and making itself comfortable next to the power unit drying heaters (Early marine equipment used drying heaters to avoid condensation). Needless to say the cat never went near again..though I got into the habit of tapping the front panel before powering up - just in case. |
#24
|
|||
|
|||
Amp Catastrophies
"Karl Uppiano" wrote in message ... "JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day In the late '70s, I worked as a contract engineer for a number of broadcast stations. One night I was doing transmitter maintenance on a 100-kilowatt FM station in a large transmitter complex at the top of a ski area near Boise ID. It was about 3:00AM, and I had just finished replacing the main power amplifier tube, and a bunch of other general maintenance. Working on high-power transmitters is always cause for a bit of nervousness, and this particular transmitter was more glitchy than others I've worked on. Anyway, I got everything finished, so I secured the doors on the refrigerator-sized cabinet, powered it up, and started tuning it up. I just about had it back up to full power when -- BANG!! -- it sounded like a shotgun going off inside the transmitter as it immediately dropped off the air. I had a mental picture of some critical, expensive, hard-to-get high-voltage component completely fried, and my client off the air for a week while we wait for parts. I powered the whole thing down, and went around back and cautiously opened the cabinet to survey the damage. The 3/4-horse cooling fan was still coasting to a stop. Inside, the air was filled with some kind of fuzz or something. What the...??? I couldn't think of any component that would throw fuzz everywhere when it exploded. Then my eye fell on an insulated stand-off mounted on the floor of the cabinet, where the main high-voltage power supply lines entered the box. There, I saw the skeleton of a mouse, with its back feet on the metal cabinet floor, and it's nose about a centimeter from the high-voltage terminal. His last act must have been a curious sniff of the 10KV power supply line. I probably wouldn't have noticed him climb in there. Anyway, I gently lifted the bone-dry skeleton out of the cabinet and restarted the transmitter, which ran just fine. So it wasn't a catastrophe for me, but the mouse probably had a different perspective, if he ever got a chance to think about it. It also explained a few other dry mouse skeletons I found in the building when I first started working there. I could describe one incident possibly a 'cat'astrophe. Many many years ago I joined a general cargo ship of the Brocklebank line as radio officer. The first time I threw the main switch to the HF transmitter there was a loud piercing shriek followed by a black blur, I shut it off immediately and investigated...couldn't find anything wrong. Sometime later I found out that the ships cat had a habit of getting into the rear of the unit while the ship was in port and making itself comfortable next to the power unit drying heaters (Early marine equipment used drying heaters to avoid condensation). Needless to say the cat never went near again..though I got into the habit of tapping the front panel before powering up - just in case. |
#25
|
|||
|
|||
Amp Catastrophies
"Karl Uppiano" wrote in message ... "JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? Vin Collins Loser of the Day In the late '70s, I worked as a contract engineer for a number of broadcast stations. One night I was doing transmitter maintenance on a 100-kilowatt FM station in a large transmitter complex at the top of a ski area near Boise ID. It was about 3:00AM, and I had just finished replacing the main power amplifier tube, and a bunch of other general maintenance. Working on high-power transmitters is always cause for a bit of nervousness, and this particular transmitter was more glitchy than others I've worked on. Anyway, I got everything finished, so I secured the doors on the refrigerator-sized cabinet, powered it up, and started tuning it up. I just about had it back up to full power when -- BANG!! -- it sounded like a shotgun going off inside the transmitter as it immediately dropped off the air. I had a mental picture of some critical, expensive, hard-to-get high-voltage component completely fried, and my client off the air for a week while we wait for parts. I powered the whole thing down, and went around back and cautiously opened the cabinet to survey the damage. The 3/4-horse cooling fan was still coasting to a stop. Inside, the air was filled with some kind of fuzz or something. What the...??? I couldn't think of any component that would throw fuzz everywhere when it exploded. Then my eye fell on an insulated stand-off mounted on the floor of the cabinet, where the main high-voltage power supply lines entered the box. There, I saw the skeleton of a mouse, with its back feet on the metal cabinet floor, and it's nose about a centimeter from the high-voltage terminal. His last act must have been a curious sniff of the 10KV power supply line. I probably wouldn't have noticed him climb in there. Anyway, I gently lifted the bone-dry skeleton out of the cabinet and restarted the transmitter, which ran just fine. So it wasn't a catastrophe for me, but the mouse probably had a different perspective, if he ever got a chance to think about it. It also explained a few other dry mouse skeletons I found in the building when I first started working there. I could describe one incident possibly a 'cat'astrophe. Many many years ago I joined a general cargo ship of the Brocklebank line as radio officer. The first time I threw the main switch to the HF transmitter there was a loud piercing shriek followed by a black blur, I shut it off immediately and investigated...couldn't find anything wrong. Sometime later I found out that the ships cat had a habit of getting into the rear of the unit while the ship was in port and making itself comfortable next to the power unit drying heaters (Early marine equipment used drying heaters to avoid condensation). Needless to say the cat never went near again..though I got into the habit of tapping the front panel before powering up - just in case. |
#26
|
|||
|
|||
Amp Catastrophies
In , on 05/22/04
at 03:22 PM, "JVC" said: [ ... ] Anyone have any boneheaded maneuvers they would like to share? While working as a technician I was assigned to terminate a 50 conductor cable. I was pleased when I got through the very boring task without melting or shorting anything. Just as I was about to pat myself on the back, I noticed the connector cover was still on the bench. Carefully, I unsoldered all 50 pins and started over. Amazingly I managed to replace all 50 conductors without melting or shorting anything. I was very pleased. Unfortunately, the cover was still on the bench! -sigh- Carefully, I unsoldered all 50 pins and started over. Amazingly I had managed to replace all 50 conductors without melting or shorting anything. I was very pleased. This time I got it right. (no I couldn't slide the cover from the other end because it had already been terminated). ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#27
|
|||
|
|||
Amp Catastrophies
In , on 05/22/04
at 03:22 PM, "JVC" said: [ ... ] Anyone have any boneheaded maneuvers they would like to share? While working as a technician I was assigned to terminate a 50 conductor cable. I was pleased when I got through the very boring task without melting or shorting anything. Just as I was about to pat myself on the back, I noticed the connector cover was still on the bench. Carefully, I unsoldered all 50 pins and started over. Amazingly I managed to replace all 50 conductors without melting or shorting anything. I was very pleased. Unfortunately, the cover was still on the bench! -sigh- Carefully, I unsoldered all 50 pins and started over. Amazingly I had managed to replace all 50 conductors without melting or shorting anything. I was very pleased. This time I got it right. (no I couldn't slide the cover from the other end because it had already been terminated). ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#28
|
|||
|
|||
Amp Catastrophies
In , on 05/22/04
at 03:22 PM, "JVC" said: [ ... ] Anyone have any boneheaded maneuvers they would like to share? While working as a technician I was assigned to terminate a 50 conductor cable. I was pleased when I got through the very boring task without melting or shorting anything. Just as I was about to pat myself on the back, I noticed the connector cover was still on the bench. Carefully, I unsoldered all 50 pins and started over. Amazingly I managed to replace all 50 conductors without melting or shorting anything. I was very pleased. Unfortunately, the cover was still on the bench! -sigh- Carefully, I unsoldered all 50 pins and started over. Amazingly I had managed to replace all 50 conductors without melting or shorting anything. I was very pleased. This time I got it right. (no I couldn't slide the cover from the other end because it had already been terminated). ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#29
|
|||
|
|||
Amp Catastrophies
In , on 05/22/04
at 03:22 PM, "JVC" said: [ ... ] Anyone have any boneheaded maneuvers they would like to share? While working as a technician I was assigned to terminate a 50 conductor cable. I was pleased when I got through the very boring task without melting or shorting anything. Just as I was about to pat myself on the back, I noticed the connector cover was still on the bench. Carefully, I unsoldered all 50 pins and started over. Amazingly I managed to replace all 50 conductors without melting or shorting anything. I was very pleased. Unfortunately, the cover was still on the bench! -sigh- Carefully, I unsoldered all 50 pins and started over. Amazingly I had managed to replace all 50 conductors without melting or shorting anything. I was very pleased. This time I got it right. (no I couldn't slide the cover from the other end because it had already been terminated). ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#30
|
|||
|
|||
Amp Catastrophies
"JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? **I was working on a big, tubed push pull power amp. It employed anode caps. My arm was 'round the back, performing a measurement and someone entered the workshop. In my surprise, I brushed my arm against the anode cap on one output tube. The amp ended up on the concrete floor. -- Trevor Wilson www.rageaudio.com.au |
#31
|
|||
|
|||
Amp Catastrophies
"JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? **I was working on a big, tubed push pull power amp. It employed anode caps. My arm was 'round the back, performing a measurement and someone entered the workshop. In my surprise, I brushed my arm against the anode cap on one output tube. The amp ended up on the concrete floor. -- Trevor Wilson www.rageaudio.com.au |
#32
|
|||
|
|||
Amp Catastrophies
"JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? **I was working on a big, tubed push pull power amp. It employed anode caps. My arm was 'round the back, performing a measurement and someone entered the workshop. In my surprise, I brushed my arm against the anode cap on one output tube. The amp ended up on the concrete floor. -- Trevor Wilson www.rageaudio.com.au |
#33
|
|||
|
|||
Amp Catastrophies
"JVC" wrote in message ... Hi Group, After spending hours rebuilding a SS guitar amp, (thanks to all who helped with IC data etc,) I got it up and running. I had to replace a couple IC's and most of the output components. As I like to keep detailed records on stuff I have repaired, I was taking voltage and scope measurements with signal applied, and making notes on the print. As I was making my final measurements with the scope probe,,,, I slipped and shorted B to C on the driver transistor. This took out most of the components in the output,, At least when you do stupid stuff like this with Toob stuff you are rewarded with a shower of sparks!! Anyone have any boneheaded maneuvers they would like to share? **I was working on a big, tubed push pull power amp. It employed anode caps. My arm was 'round the back, performing a measurement and someone entered the workshop. In my surprise, I brushed my arm against the anode cap on one output tube. The amp ended up on the concrete floor. -- Trevor Wilson www.rageaudio.com.au |
#34
|
|||
|
|||
Amp Catastrophies
In article ,
"Arny Krueger" wrote: Kevin McMurtrie wrote: Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. I spent a summer before grad school working on a prototype electric-powered delivery truck. It was powered by over a dozen of the largest golf cart batteries anybody made at the time. There were three battery boxes, each of which weighed something like a ton. The battteries in each box were connected in series so there was about 80 volts across each string. In paralell and fresh, they could deliver over 1,000 amps into a 72 volt DC motor via a SCR controller, for something like a minute. The contacts were at one end of the box, and to my chagrin I found that it was possible to short them out. They were hooked in series for charging with a transformerless battery charger operating off of a 240 volt three-phase power line. I had this little accident where I dropped a screw driver with a foot-long blade that could have doubled for a small crowbar. In one blue flash the screwdriver lost about half its length, and I was covered with many spatters of steel and copper. The good news is that I had safety glasses on and had turned away before actual contact was made. So, I was neither blinded nor did I need to visit a hospital. My tempered glass safety glasses had spatters of copper and steel melted into them to the extent that they had to be replaced. My face and forearms had little b-b sized chunks of copper and steel seared into them. But, in a week or two they mostly all fell out on their own. My clothes were perferated and had to be scrapped. The lesson was that batteries generally don't have effective power-off switches on them. Ouch! That reminds me of when I first tried melting a carbon rod. It sputtered, causing little fireballs of molten carbon to burn through everything they touched down to the concrete floor. I looked down and saw one ball drop through a can of paint thinner! Luckily the can had been sealed long enough to have run out of oxygen. |
#35
|
|||
|
|||
Amp Catastrophies
In article ,
"Arny Krueger" wrote: Kevin McMurtrie wrote: Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. I spent a summer before grad school working on a prototype electric-powered delivery truck. It was powered by over a dozen of the largest golf cart batteries anybody made at the time. There were three battery boxes, each of which weighed something like a ton. The battteries in each box were connected in series so there was about 80 volts across each string. In paralell and fresh, they could deliver over 1,000 amps into a 72 volt DC motor via a SCR controller, for something like a minute. The contacts were at one end of the box, and to my chagrin I found that it was possible to short them out. They were hooked in series for charging with a transformerless battery charger operating off of a 240 volt three-phase power line. I had this little accident where I dropped a screw driver with a foot-long blade that could have doubled for a small crowbar. In one blue flash the screwdriver lost about half its length, and I was covered with many spatters of steel and copper. The good news is that I had safety glasses on and had turned away before actual contact was made. So, I was neither blinded nor did I need to visit a hospital. My tempered glass safety glasses had spatters of copper and steel melted into them to the extent that they had to be replaced. My face and forearms had little b-b sized chunks of copper and steel seared into them. But, in a week or two they mostly all fell out on their own. My clothes were perferated and had to be scrapped. The lesson was that batteries generally don't have effective power-off switches on them. Ouch! That reminds me of when I first tried melting a carbon rod. It sputtered, causing little fireballs of molten carbon to burn through everything they touched down to the concrete floor. I looked down and saw one ball drop through a can of paint thinner! Luckily the can had been sealed long enough to have run out of oxygen. |
#36
|
|||
|
|||
Amp Catastrophies
In article ,
"Arny Krueger" wrote: Kevin McMurtrie wrote: Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. I spent a summer before grad school working on a prototype electric-powered delivery truck. It was powered by over a dozen of the largest golf cart batteries anybody made at the time. There were three battery boxes, each of which weighed something like a ton. The battteries in each box were connected in series so there was about 80 volts across each string. In paralell and fresh, they could deliver over 1,000 amps into a 72 volt DC motor via a SCR controller, for something like a minute. The contacts were at one end of the box, and to my chagrin I found that it was possible to short them out. They were hooked in series for charging with a transformerless battery charger operating off of a 240 volt three-phase power line. I had this little accident where I dropped a screw driver with a foot-long blade that could have doubled for a small crowbar. In one blue flash the screwdriver lost about half its length, and I was covered with many spatters of steel and copper. The good news is that I had safety glasses on and had turned away before actual contact was made. So, I was neither blinded nor did I need to visit a hospital. My tempered glass safety glasses had spatters of copper and steel melted into them to the extent that they had to be replaced. My face and forearms had little b-b sized chunks of copper and steel seared into them. But, in a week or two they mostly all fell out on their own. My clothes were perferated and had to be scrapped. The lesson was that batteries generally don't have effective power-off switches on them. Ouch! That reminds me of when I first tried melting a carbon rod. It sputtered, causing little fireballs of molten carbon to burn through everything they touched down to the concrete floor. I looked down and saw one ball drop through a can of paint thinner! Luckily the can had been sealed long enough to have run out of oxygen. |
#37
|
|||
|
|||
Amp Catastrophies
In article ,
"Arny Krueger" wrote: Kevin McMurtrie wrote: Try shorting the gate of a TO-220 MOSFET that's driving an inductor. It sprays plasma-heated silver with explosive force. The result either looks very cool or really stings, depending on how close you are. I spent a summer before grad school working on a prototype electric-powered delivery truck. It was powered by over a dozen of the largest golf cart batteries anybody made at the time. There were three battery boxes, each of which weighed something like a ton. The battteries in each box were connected in series so there was about 80 volts across each string. In paralell and fresh, they could deliver over 1,000 amps into a 72 volt DC motor via a SCR controller, for something like a minute. The contacts were at one end of the box, and to my chagrin I found that it was possible to short them out. They were hooked in series for charging with a transformerless battery charger operating off of a 240 volt three-phase power line. I had this little accident where I dropped a screw driver with a foot-long blade that could have doubled for a small crowbar. In one blue flash the screwdriver lost about half its length, and I was covered with many spatters of steel and copper. The good news is that I had safety glasses on and had turned away before actual contact was made. So, I was neither blinded nor did I need to visit a hospital. My tempered glass safety glasses had spatters of copper and steel melted into them to the extent that they had to be replaced. My face and forearms had little b-b sized chunks of copper and steel seared into them. But, in a week or two they mostly all fell out on their own. My clothes were perferated and had to be scrapped. The lesson was that batteries generally don't have effective power-off switches on them. Ouch! That reminds me of when I first tried melting a carbon rod. It sputtered, causing little fireballs of molten carbon to burn through everything they touched down to the concrete floor. I looked down and saw one ball drop through a can of paint thinner! Luckily the can had been sealed long enough to have run out of oxygen. |
#38
|
|||
|
|||
Amp Catastrophies
Trevor Wilson wrote:
**I was working on a big, tubed push pull power amp. It employed anode caps. My arm was 'round the back, performing a measurement and someone entered the workshop. In my surprise, I brushed my arm against the anode cap on one output tube. The amp ended up on the concrete floor. My stepfather had a Phase Linear 400 make it's infamous POP and it took out the the 16 ohm drivers in two Electrovice Patricians, one 400 and a IV both original from the early 50's. -- Check out the gaming & computer forums at the [SS] clan site. http://www.shamikaserver.com |
#39
|
|||
|
|||
Amp Catastrophies
Trevor Wilson wrote:
**I was working on a big, tubed push pull power amp. It employed anode caps. My arm was 'round the back, performing a measurement and someone entered the workshop. In my surprise, I brushed my arm against the anode cap on one output tube. The amp ended up on the concrete floor. My stepfather had a Phase Linear 400 make it's infamous POP and it took out the the 16 ohm drivers in two Electrovice Patricians, one 400 and a IV both original from the early 50's. -- Check out the gaming & computer forums at the [SS] clan site. http://www.shamikaserver.com |
#40
|
|||
|
|||
Amp Catastrophies
Trevor Wilson wrote:
**I was working on a big, tubed push pull power amp. It employed anode caps. My arm was 'round the back, performing a measurement and someone entered the workshop. In my surprise, I brushed my arm against the anode cap on one output tube. The amp ended up on the concrete floor. My stepfather had a Phase Linear 400 make it's infamous POP and it took out the the 16 ohm drivers in two Electrovice Patricians, one 400 and a IV both original from the early 50's. -- Check out the gaming & computer forums at the [SS] clan site. http://www.shamikaserver.com |