I let the smoke out of my amplifier

As we all know, smoke is built into electronic devices, and when you let this smoke out, the device doesn't work anymore.

My JBL amp needs new smoke now. It was an inexpensive used unit, that worked fine and lasted about a year. I noticed the left channel went quiet and when I checked it with the fader and balance controls both rear channels went out. I didn't actually see the smoke but I smelled it when I opened the trunk.

Now I've got two bad JBL amps. I'm going to try to combine the parts to get one good amp out of them. I'm not going to waste too much time on it, it will actually be a winter project, when I can't be outside washing and waxing my cars.

I've got an electronics background, but a schematic diagram of the amplifier would help a lot. Would the EVTM (?) manual have it?

Does anyone have a schematic or know where I could get one?

Here's a photo of where the smoke leaked out :

I do not recall any such detail schematics in the EVTM, just a general wiring layout between components.

The damage appears fairly localized and all the components appear identifiable. I wouldn't swap parts, I would ID what parts were needed and try substituting them on the board.

WOW! You released ALOT of smoke. I work for motorola in their 2-way radio division. We make all the high-end public safety radios and the systems. I deal with this type of stuff everyday. That is some major smoke release. I would be shocked if the board is reusable, but you never know. The internal layers may still be OK. This would be an automatic scrap situation here.

If that IS a sandwich board, it's toast unless you have a schematic the runs so you can use wire to simulate them.

Yeah, I won't be re using this board. I'm just hoping that some of the other components on the other channels are OK for my other bad amp. It still has it's smoke, it just has that static and squeal problem sometimes.

I can probably do it without the schematic but, it would be easier if I had one.

For now I'm going to use my amp from a 97 (thanks again Jeremi) as soon as I get the right wire connector for it.

Audio amps are pretty simple I used to fix that stuff years ago when I was a technician. That board probably doesn't have inner layers (I have repaired worse) because the circuit is pretty simple and straitforward. If it is a high power (more than 25 or so watts) I would look at the switching transistors in the DC to Dc converter first if it doesn't have a switchmode power supply it is going to be the audio output transistors. Hopefully the PWM regulator chip (if it has a switchmode power suply in it) didn't let it's smoke out also. I would check what caused the switching transistors (if equipped) to take a dive such as the audio output transistors on the channel that took a dive before the rest died.

Actually don't spend a great deal of time on it because car amplifiers are real cheap these days considering there capabilities.

Thanks for the info Steve, I used to repair all my electronics too. Lateley though, like you say, it's often cheaper to buy new. Some of the parts used in 1994 might be pretty hard to find now too.

When I was a kid, I used to repair TV's, using vacuum tubes, that I found on trash day, when people threw their TV's away. Those were the good old days.

I still have a good supply of (expensive now) tubes, and I still use them in my collection of antique instrumentation and radios.

Bill, I pulled my shop manuals and all the EVTM shows is the basic stuff for the componentry and nothing about the amp in detail. If you want I can send you copies of what's there. Mine is for "96".

Thanks Charlie, but it sounds like you've got the same thing that I do with my regular service manual.

I've contacted JBL and haven't heard back from them yet.

I'm going to try Ford next.

I hope it works out for you. Maybe I could bring Darth up there some time and you could do a little "tunning" on it as it' radio reception and amp is acting strange. That is once you get yours all back to gether. We probably should also slip over to J's to check up on him too as I smell smoke coming from his place. LOL

Sounds good Charlie. I hope to get the schematic eventually, it might come in handy in the future as all our cars get older. These amplifiers seem to go bad more often now, and a lot of us might want to keep the stock systems going if possible.

It sure would be nice to have the schematic diagrams for all of the "modules" in our cars. One of these days a good working replacement might not be available.

I talked to J on the phone today. He's been busy at work lateley but we should all get together again soon. We could have a bar be que at my house this time, it's an hour closer to you.

I am not trying to be a wiseguy but I am just curious. Are you fixing the original JBL amplifier to keep the car all original or is there maybe a fitment problem with aftermarket amplifiers? I guess that I have a different way of looking at things but if my JBL amplifier broke I would probably just find an aftermarket one that fits in the same space splice in the connectors for power, remote turn on audio etc and call it a day. It would probably also take months before I address the problem because I just don't have time to do things these days! My head unit doesn't work correctly because I was stupid enough to open my drivers side window because it was fogged up and a plow threw snow mixed with salt into my car. Since then if for any reason you end up in AM it takes a special sequence of buttons to go back to FM and for the life of me I don't remember what the sequence is. I usually just take a cloth and pretend that I am cleaning it rubbing across the buttons with the radio turned on and within 30 sec or so it goes back into FM mode.

I'll answer it this way, I am just cheap and if a bud like Bill can come up with a tune for me I'm in. Besides what a better excuse to embibe in more suds. Bar-B-Q sounds great !!

The suds and Bar-B-Q are good enough reason for me! If you guys weren't 1000 or so miles away I would probably offer to help! Like Bill I learned with tubes and progressed to contemporary electronics. And like Bill I have my share of antique radio equipment!