Hey guys,
Now tell me honestly, does anyone really attempt to repair an amp like the one pictured which can be purchased for around $500.00?
Look at this thing...Unless Peavey has a bulletin about some well known problem, at this point in my career, with about 20 guitar/bass amps to repair, why even bother. It powers up, then goes into protection by shutting off.
Maybe I'm just getting old
Glen
Peavey_IPR2_5000.jpg
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A class D amplifier is a special case of a switching power supply; it's a power supply set up so it can be fed a variable reference voltage that goes either positive or negative, and can respond fast enough to change output voltage to produce audio. They have much the same weaknesses and failure points as any other high frequency switching power supply. That is, the controller IC(s) may have gone mad, or a power device in the output stage has failed. You'll need a good scope, because the thing may be switching at upwards of half to one megahertz.
Before you throw it away, check the power devices and voltage on the ICs.
"It's not what we don't know that gets us in trouble. It's what we know for sure that just ain't so"
Mark Twain
For the inexpensive class d stuff I usually don't bother. Occasionally I get ambitious and try to fix them, sometimes i'm even successful, but it's rarely worth the time. I think most manufacturers have switched to using ICE brand modules or similar and you can just swap them out. It was only like $130 for a 250w ICE module last time I checked.
Hello RG.
I do understand how the SMPS & DClass systems work and have repaired smaller less powerful types, but honestly something this powerful and complex I'd rather leave it to folks that have expertise as well as have all the correct original semiconductors AND access to service bulletins. I've gotten to where I just send the amp modules for power monitors to facilities that do this all the time & have access to the manufacturer for bulletins & tech support such as the JBL stuff. I've had them return power modules with notes about the repair that includes updating per service bulletins.
So with this one, Chris @ Peavey is suggesting sending it to his facility & just letting the factory techs work on it. Frankly, I'm all for that at this point, esp when I have over 20 guitar/bass amps to repair in the line-up.
Thanx for the response! Nice to be back on a tech site now that it appears MEF is gone
I can get on board with that. A major part of fixing stuff like this is having the equipment and setup to look at it. If you have access to a repair station that does it, it's probably going to be cheaper and faster.
I spent several years designing switching power supplies 100W to 1kW. It's touchy stuff. I don't blame you a bit for not wanting to dig into it. Frankly, the economics say that just replacing whole PCBs is cheaper than reworking them. The skilled labor cost is more than the cost of a new, tested and working board. We always went to some length to estimate the field failure rates of the things we designed. This was used to estimate the cost of simply building the repair parts inventory at the same time as the original build for a run of machines. Just building extras was cheaper than any of skilled field repair, repair station repair, or re-starting a line that had been shut down and re-purposed.
I know this stuff, but I don't particularly like it.
"It's not what we don't know that gets us in trouble. It's what we know for sure that just ain't so"
Mark Twain
