Old peavy has no power

[Dallaspezz]

The bass player in my group left his peavy combo 300 at my house and it doesn't seem to switch on, anymore. It used to take a long time to get going or only switch on certain times. Now, there's nothing. I've checked all the fuses with a meter and they're fine, all the wires are connected. Could it be the transformer? Any ways to fix it?

 

[BassmanPaul]

Take the amp to a tech to get it repaired. From your last two questions it seems obvious that you do not have the skills to repair the unit.

Where are you in our fair province?

 

[Dallaspezz]

Take the amp to a tech to get it repaired. From your last two questions it seems obvious that you do not have the skills to repair the unit.

Where are you in our fair province?

South of Barrie. I was just wondering if it's a home job, If it's not , I'm just going to send it back to my bassist.

 

[nashvillebill]

I dunno why, every time an amp has issues, folks almost reflexively ask "is it the transformer" when in reality, transformers tend to be among the most robust items in an amp (with the exception of some newer amps which have thermal fuses wound into the power transformer).

Old transformers very rarely fail, and when they do, they typically stay failed, intermittent faults inside transformers are relatively rare. Whereas, mechanical items like switches fail quite regularly. Wires in the power cable are constantly flexed, and can fail to cause such an intermittent fault.

Yep, take it to a tech. A qualified tech can likely find this problem very quickly, whereas a novice with no troubleshooting skills could easily electrocute themselves when dealing with primary power issues.

 

[Dallaspezz]

I

I dunno why, every time an amp has issues, folks almost reflexively ask "is it the transformer" when in reality, transformers tend to be among the most robust items in an amp (with the exception of some newer amps which have thermal fuses wound into the power transformer).

Old transformers very rarely fail, and when they do, they typically stay failed, intermittent faults inside transformers are relatively rare. Whereas, mechanical items like switches fail quite regularly. Wires in the power cable are constantly flexed, and can fail to cause such an intermittent fault.

Yep, take it to a tech. A qualified tech can likely find this problem very quickly, whereas a novice with no troubleshooting skills could easily electrocute themselves when dealing with primary power issues.

I had a few family friends who are electricians look at it. They think it's the transformer, I assume amps are different than what electricians commonly work on.

 

[Clark Dark]

What's funny is while lots of folks say "is it the transformer" none of them will unplug the amp from wall voltage and put the "meter" across the poles of the switch which more often than not is the culprit.

 

[mapleglo]

Many years ago, a friend of mine had an old Hammond organ, which powered up, and the internal Leslie speaker spun, but the unit made no sound. He offered it to me for $50.00. I bought it, powered it up, and started tracing the power from where it came into the unit. Obviously, it's first internal connection was to the amp/leslie section. After that, it went to the organ itself. The wire had come loose from the actual connector that provided the organ power. Resoldered it, and the thing worked. I eventually sold it for $300.00.

 

[Systolic]

As the the "Parts Guy" for one of the largest parts vendors in the country, i talk to a lot of techs and repair shops, and we go through a boat load of transformers on peaveys (older and newer.) I'm not saying that's what is wrong with the unit, but I will refute the idea that transformers don't go bad often.

 

[B-string]

Sure "techs" will blame a transformer then after they install that expensive transformer and it still doesn't work they are forced to find the actual problem. I have seen this way too many times.

 

[nashvillebill]

As the the "Parts Guy" for one of the largest parts vendors in the country, i talk to a lot of techs and repair shops, and we go through a boat load of transformers on peaveys (older and newer.) I'm not saying that's what is wrong with the unit, but I will refute the idea that transformers don't go bad often.

Often, though, they have been burnt out because the output transistors were shorted, and the fuse blew, so the user put a bigger fuse in. Yes, transformers go, but statistically, there's a boatload of Peaveys out there, so yes there will be a lot of replacement PT's sold.

Typically, when an amp comes in dead, I start tracing continuity across the power switch and fuse, leaving the transformer to the last check.

 

[Dallaspezz]

On

Often, though, they have been burnt out because the output transistors were shorted, and the fuse blew, so the user put a bigger fuse in. Yes, transformers go, but statistically, there's a boatload of Peaveys out there, so yes there will be a lot of replacement PT's sold.

Typically, when an amp comes in dead, I start tracing continuity across the power switch and fuse, leaving the transformer to the last check.

i tested the switch, it's dead. I'm going to get a new one, if that doesn't work I'm going to take it to a tech. Thanks, everyone

 

[BassmanPaul]

The OP is 17 years old. I would not advise him poking around inside any kind of amplifier without first getting a grounding in electronic repair. It's very easy to make a $100 repair bill into a $500 one.

 

[B-string]

Peavey also used triacs a lot. The power switch through a NC thermal switch on the power amp heatsink to the gate on a triac to control mains voltage to the power transformer. Anyone care to take responsibility for the life or property of a person over the internet to explain proper testing?

 

[agedhorse]

I gave been in this industry my entire adult life, designing and managing service/parts programs. I can say with only a few notable exceptions (related to design deficiencies or identified manufacturing defects) that transformers are probably one of the most reliable components in an amplifier and rarely fail on their own.

 

[Dallaspezz]

The OP is 17 years old. I would not advise him poking around inside any kind of amplifier without first getting a grounding in electronic repair. It's very easy to make a $100 repair bill into a $500 one.

I had electricians look at it, I just tested the fuses

 

[nashvillebill]

Electricians are good at wiring houses, but typically not very good at repairing amps.

Note, many older Peaveys used an on-off-on DPDT switch with Class XY caps for noise control. Care must be taken when changing that switch. Please have a qualified tech work on it.

 

[BassmanPaul]

I had electricians look at it, I just tested the fuses

I'm not "getting at you." I'm just concerned for your safety. I built my first tube amp, a record player, when I was about 13 or 14. Sometimes young folk charge ahead before they should, as I have done many times, is all I'm saying. Testing fuses is one thing opening an amplifier up, as happens all too many times on this site, is another. Had you been closer I would have take a look for you.

 

[Dallaspezz]

I'm not "getting at you." I'm just concerned for your safety. I built my first tube amp, a record player, when I was about 13 or 14. Sometimes young folk charge ahead before they should, as I have done many times, is all I'm saying. Testing fuses is one thing opening an amplifier up, as happens all too many times on this site, is another. Had you been closer I would have take a look for you.

I understand, It's hard to tell over the internet lol. I think it's the switch, as I said. It doesn't give any power when I tested it. I'll buy a switch and see what happens

 

[BassmanPaul]

Make sure you unplug the amp before installing the switch!!

 

[agedhorse]

Have you TESTED the switch?