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#1
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Did I fry my Chu Moy Amp?
I plugged in a 12v AC adaptor and I think it was designed for DC. It started
burning, etc. etc. and no longer works. What did I do exactly? |
#2
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On Thu, 02 Sep 2004 06:59:28 GMT, "Asterix"
wrote: I plugged in a 12v AC adaptor and I think it was designed for DC. It started burning, etc. etc. and no longer works. What did I do exactly? You broke it. If you're lucky, you just fried a few components in the power input section. What's a Chu Moy? Is it expensive enough to be worth taking to a repair shop? If not, bin it and be more careful about using the correct power supply in future :-) |
#3
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"Laurence Payne" wrote in
message On Thu, 02 Sep 2004 06:59:28 GMT, "Asterix" wrote: I plugged in a 12v AC adaptor and I think it was designed for DC. It started burning, etc. etc. and no longer works. What did I do exactly? You broke it. If you're lucky, you just fried a few components in the power input section. What's a Chu Moy? http://www.headwize.com/projects/sho...=cmoy2_prj.htm Is it expensive enough to be worth taking to a repair shop? Many are self-built it seems. If not, bin it and be more careful about using the correct power supply in future :-) A few cheap diodes would make it more goof-proof. |
#4
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I plugged in a 12v AC adaptor and I think it was designed for DC.
You're right. It's designed for DC - specifically, DC with some amount of regulation. It can probably work with a filtered-but- not-regulated DC supply, but there may be some amount of hum on the signal as a result. It started burning, etc. etc. and no longer works. What did I do exactly? If this was built according to the circuitry at www.headwize.com, it appears that there's no reverse polarity protection. AC would definitely be bad for it. Feeding AC into it would have put a high amount of ripple current through the filter capacitors (C1 and C2) and would have reverse-polarized them during half of each cycle. This might have caused a catastrophic failure (swelling, leaking, venting of the cap cans themselves) or, at least, have changed their electrical characteristics. Feeding in AC would also have caused reverse voltage to be fed to the power supply pins of the OP134A op amps, and I suspect that this would likely have destroyed them. I think you'll certainly need two new op amps. It'd probably be a good idea to replace C1 and C2 as well. Adding anti-polarity-reversal diodes to the power supply input would be an excellent ideas, as well. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#5
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A few cheap diodes would make it more goof-proof. Did I tell you about my Sony Walkman Professional? This expensive unit can't tolerate reversed polarity on the 6v input. As you say - a few pennies spent on a diode.... |
#6
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Laurence Payne wrote:
A few cheap diodes would make it more goof-proof. Did I tell you about my Sony Walkman Professional? This expensive unit can't tolerate reversed polarity on the 6v input. As you say - a few pennies spent on a diode.... But then they would have to up the volts / watts / price on the ac adaptor ! Graham |
#7
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Yes, I think it was built according to those plans, it is a popular design
and a few people are selling them on e-bay. I got mine for about $60 and had to fight to get it, about 15 people bid. Anyway, I'm recieved a response from the guy via e-mail, I don't know what he can do now that it's destroyed but we'll see... "Dave Platt" wrote in message ... I plugged in a 12v AC adaptor and I think it was designed for DC. You're right. It's designed for DC - specifically, DC with some amount of regulation. It can probably work with a filtered-but- not-regulated DC supply, but there may be some amount of hum on the signal as a result. It started burning, etc. etc. and no longer works. What did I do exactly? If this was built according to the circuitry at www.headwize.com, it appears that there's no reverse polarity protection. AC would definitely be bad for it. Feeding AC into it would have put a high amount of ripple current through the filter capacitors (C1 and C2) and would have reverse-polarized them during half of each cycle. This might have caused a catastrophic failure (swelling, leaking, venting of the cap cans themselves) or, at least, have changed their electrical characteristics. Feeding in AC would also have caused reverse voltage to be fed to the power supply pins of the OP134A op amps, and I suspect that this would likely have destroyed them. I think you'll certainly need two new op amps. It'd probably be a good idea to replace C1 and C2 as well. Adding anti-polarity-reversal diodes to the power supply input would be an excellent ideas, as well. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#8
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Did I tell you about my Sony Walkman Professional? This expensive unit can't tolerate reversed polarity on the 6v input. As you say - a few pennies spent on a diode.... But then they would have to up the volts / watts / price on the ac adaptor ! Graham Not if you put a single (reversed) diode from input to ground. I've seen this often and the diode usually burns short. Better a blown PSU. Gareth. |
#9
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In article r4RZc.3282$A63.1670@trnddc09, "Asterix" wrote:
Yes, I think it was built according to those plans, it is a popular design and a few people are selling them on e-bay. I got mine for about $60 and had to fight to get it, about 15 people bid. Anyway, I'm recieved a response from the guy via e-mail, I don't know what he can do now that it's destroyed but we'll see... I think just replace the op-amp, especially if its mounted in a socket?? greg "Dave Platt" wrote in message ... I plugged in a 12v AC adaptor and I think it was designed for DC. You're right. It's designed for DC - specifically, DC with some amount of regulation. It can probably work with a filtered-but- not-regulated DC supply, but there may be some amount of hum on the signal as a result. It started burning, etc. etc. and no longer works. What did I do exactly? If this was built according to the circuitry at www.headwize.com, it appears that there's no reverse polarity protection. AC would definitely be bad for it. Feeding AC into it would have put a high amount of ripple current through the filter capacitors (C1 and C2) and would have reverse-polarized them during half of each cycle. This might have caused a catastrophic failure (swelling, leaking, venting of the cap cans themselves) or, at least, have changed their electrical characteristics. Feeding in AC would also have caused reverse voltage to be fed to the power supply pins of the OP134A op amps, and I suspect that this would likely have destroyed them. I think you'll certainly need two new op amps. It'd probably be a good idea to replace C1 and C2 as well. Adding anti-polarity-reversal diodes to the power supply input would be an excellent ideas, as well. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |