Home |
Search |
Today's Posts |
#1
Posted to rec.audio.pro
|
|||
|
|||
Need help diagnosing bad mixer channel
I have a little Yamaha 8 channel mixer, about 3 years old, that I use
for live performances, and channel 1 is malfunctioning. I'm hoping this is something I might be able to repair myself, I don't want to spend a couple hundred bucks having a $300 mixer repaired. I also don't want to buy another mixer. I'm fairly handy with a soldering iron, and have a cheap multimeter and rudimentary electronics knowledge. I use this mixer frequently and I'm hoping I can perform a satisfactory homebrewed repair to get it back in action. The symptoms: The input and preamp seem to be working, but there is no signal getting to the main outs from this channel. I can hook up a mic or instrument and see the input level on the LED meter, but when I un-mute the channel there is no sound from the main outs. I havn't tried to see if the aux sends are getting a signal from it yet. The gain pot works but seems 'weak' compared to the other channels, ie I have to turn the preamp gain up pretty high on this channel to see the same levels on the meter as a much lower gain on the other channels. I don't know if this could be as simple as a connection came unsoldered inside, or if an internal component might actually need replacing. What are some possibilities, and what non-obvious things should I look for when I open it up? Things I can test with the multimeter? thanks, Brian |
#2
Posted to rec.audio.pro
|
|||
|
|||
Need help diagnosing bad mixer channel
"Brian" wrote in message ... I have a little Yamaha 8 channel mixer, about 3 years old, that I use for live performances, and channel 1 is malfunctioning. I'm hoping this is something I might be able to repair myself, I don't want to spend a couple hundred bucks having a $300 mixer repaired. I also don't want to buy another mixer. I'm fairly handy with a soldering iron, and have a cheap multimeter and rudimentary electronics knowledge. I use this mixer frequently and I'm hoping I can perform a satisfactory homebrewed repair to get it back in action. The symptoms: The input and preamp seem to be working, but there is no signal getting to the main outs from this channel. I can hook up a mic or instrument and see the input level on the LED meter, but when I un-mute the channel there is no sound from the main outs. I havn't tried to see if the aux sends are getting a signal from it yet. The gain pot works but seems 'weak' compared to the other channels, ie I have to turn the preamp gain up pretty high on this channel to see the same levels on the meter as a much lower gain on the other channels. I don't know if this could be as simple as a connection came unsoldered inside, or if an internal component might actually need replacing. What are some possibilities, and what non-obvious things should I look for when I open it up? Things I can test with the multimeter? thanks, Brian Brian you need to send a steady test signal into your mixer to evaluate the gain diffrence issue I am not a tech but I will bet you find your board is heavily constructed with surface mount technology not impossible to repair but it takes a higher level of skill than most"people handy with a iron" can muster also you need to test the aux send to determine where the signal is bad a good place to start is cleaning the insert jacks they are switching jacks and dirt/odidation there can cause problems similar to what your describing but again I am NOT a bench tech, and my info is base on what this NOT A BENCH tech has picked up randomly over the years George |
#3
Posted to rec.audio.pro
|
|||
|
|||
Need help diagnosing bad mixer channel
Brian you need to send a steady test signal into your mixer to evaluate the gain diffrence issue I am not a tech but I will bet you find your board is heavily constructed with surface mount technology not impossible to repair but it takes a higher level of skill than most"people handy with a iron" can muster also you need to test the aux send to determine where the signal is bad a good place to start is cleaning the insert jacks they are switching jacks and dirt/odidation there can cause problems similar to what your describing but again I am NOT a bench tech, and my info is base on what this NOT A BENCH tech has picked up randomly over the years George thanks for the feedback. dirt in the insert jack or elsewhere is highy probable considering the working conditions this mixer typically endures . I'll check that out. Maybe it just needs a good cleaning. By surface mount, you mean the components are probably all attached to a single circuit board? You're right, I probably can't replace anything myself if that's the case. |
#4
Posted to rec.audio.pro
|
|||
|
|||
Need help diagnosing bad mixer channel
"Brian" wrote in message ... I have a little Yamaha 8 channel mixer, about 3 years old, that I use for live performances, and channel 1 is malfunctioning. I'm hoping this is something I might be able to repair myself, I don't want to spend a couple hundred bucks having a $300 mixer repaired. I also don't want to buy another mixer. I'm fairly handy with a soldering iron, and have a cheap multimeter and rudimentary electronics knowledge. I use this mixer frequently and I'm hoping I can perform a satisfactory homebrewed repair to get it back in action. The symptoms: The input and preamp seem to be working, but there is no signal getting to the main outs from this channel. I can hook up a mic or instrument and see the input level on the LED meter, but when I un-mute the channel there is no sound from the main outs. I havn't tried to see if the aux sends are getting a signal from it yet. The gain pot works but seems 'weak' compared to the other channels, ie I have to turn the preamp gain up pretty high on this channel to see the same levels on the meter as a much lower gain on the other channels. I don't know if this could be as simple as a connection came unsoldered inside, or if an internal component might actually need replacing. What are some possibilities, and what non-obvious things should I look for when I open it up? Things I can test with the multimeter? thanks, Brian If the mixer has insert jack sockets on each channel, it is probably dirty and causing an intermittent signal. Try plugging and unplugging a jack plug a few times and the dirty contact may clean itself. Next you could try all the switches that cut or send the signal to the main outs such as mute, route to main or groups etc. If any are dirty, operating them a few times, as with the inserts, may clean the contacts. If this doesn't work, and the channels do have insert sockets, try plugging a signal straight into the insert socket. You may have to only push it in one click as it is a stereo jack socket. If all is well (compare with another channel) then the problem is somewhere between the input sockets and the insert socket. Gareth. |
#5
Posted to rec.audio.pro
|
|||
|
|||
Need help diagnosing bad mixer channel
If the mixer has insert jack sockets on each channel, it is probably dirty and causing an intermittent signal. Try plugging and unplugging a jack plug a few times and the dirty contact may clean itself. Next you could try all the switches that cut or send the signal to the main outs such as mute, route to main or groups etc. If any are dirty, operating them a few times, as with the inserts, may clean the contacts. If this doesn't work, and the channels do have insert sockets, try plugging a signal straight into the insert socket. You may have to only push it in one click as it is a stereo jack socket. If all is well (compare with another channel) then the problem is somewhere between the input sockets and the insert socket. Gareth. Each of the 6 XLR channels does have an insert jack, including the bad channel. From the responses, sounds like this is a likely culprit! I'll check it out this evening. |
#6
Posted to rec.audio.pro
|
|||
|
|||
Need help diagnosing bad mixer channel
If all is well (compare with
another channel) then the problem is somewhere between the input sockets and the insert socket. If not, probably the fader or its wiring. |
#7
Posted to rec.audio.pro
|
|||
|
|||
Need help diagnosing bad mixer channel
On Mar 22, 8:52 am, Brian wrote:
I don't know if this could be as simple as a connection came unsoldered inside, or if an internal component might actually need replacing. What are some possibilities, and what non-obvious things should I look for when I open it up? Things I can test with the multimeter? All of those are possibilities, but a multimeter won't tell you very much. The best troubleshooting tool (along with a schematic and the knowledge to read it, of course) is an oscilloscope so you can put in a steady sine wave signal and see how it changes as you move through the channel signal path. Next best is a headphone amplifier and a probe on the input so you can at least listen to tell if the signal drops significantly when it shouldn't or if it becomes distorted at some point. And while you're probing around in there, maybe you'll stumble on a loose connector or bad solder joint. |
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
4 Channel mixer comparison ? | Pro Audio | |||
FS dangerous 8 channel mixer | Pro Audio | |||
Needed: Help Diagnosing Weak R Channel on HK Citation 14 Tuner | Tech | |||
Needed: Help Diagnosing Weak R Channel on HK Citation 14 Tuner | Marketplace | |||
good 12-16 channel mixer around $500 | Pro Audio |