Here's a DIY rundown...
http://www.howtoalmanac.com...65AudioAmpRepair.htm
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Also...



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[This message has been edited by fierosound (edited 09-03-2020).]

Might fix some problems... Or fix unit won't last long after.

Bigger problem is Many using same "power plug" as Fiero are "dead" w/ old age from dried out caps etc.
25+ years of getting cooked by parked in sun, freezing in Winter, can kill many electric parts even made to work it hot/cold environments.
And I'm not confusing w/ China Cap problems either.

Even "Radios" build in 90's w/ "new style" plugs are started dying for same reasons.
I get cheap or free radios that are mostly dead w/ crap solder joints, dead caps, etc. I think have 5 units now (3 old type & 2 new type plugs) and 4 are "dead" w/ several reasons...
Examples:
My OE Unit still in the car now has something "died" and can't even keep clock working w/o main power. Yes, I checked the 2 wire plug...
Other is just completely died in storage. Was working when pulled. now nothing.

Other car brands often have same issue in car's > 20+ years old.

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The Ogre's Fiero Cave

Great info just at the right time. My Pontiac GM CD/Radio player installed in my 87GT just stopped working. The clock works but no sound from the radio on either channel. Could both audio amplifiers have gone bad? In any event replacing four caps and two amplifiers doesn't sound like a difficult fix. It could also be that the power supply lines could have been cut or maybe its a bad pin on the power supply connector but the clock works so I'm leaning towards the amps..

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A DIY on the cassette mechanism.
http://www.gnttype.org/tech...ges/tape_player.html
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Cassette drive belts...
GM/Delco Autosound Cassette Players 1980 thru mid-1990's made in 4 styles.
(1) Non-auto reverse models use SBX7.4
(2) Auto reverse Fijitsu 3 (Mechanical) Button Mechanisms use SBS8.6
(3) Auto reverse Blaupunkt 4-button Mechanisms use 2 belts: AV-SBS4.9 & AV-SBS9.2
(4)Pioneer (88 up) and Alpine Mechanisms (91 up) have electronic switch buttons SBS9.2
http://kenselectronics.com/lists/belts.htm#Auto

On Blaupunkt units, the Pulse Generator Disk (Delco PN 1226632) is sometimes the culprit.
https://www.ebay.com/itm/De...ng-Disc/124095797548

[This message has been edited by fierosound (edited 08-26-2020).]

I frequently fix electronics just by replacing old capacitors, it's not surprising capacitors exposed to temperature extremes and 30+ years old are starting to fail now.

I'm surprised we aren't seeing Fiero computers starting to go bad.

quote Originally posted by RWDPLZ: I'm surprised we aren't seeing Fiero computers starting to go bad.

I can't imagine an ECM containing much bulk electrolytic capacitance.

Probably contains largely ceramic class 2 dielectric, but the aging of that goes with log(time), so if it's stable now, the computer will probably continue to work for quite a while.

Depends on what other parts could go bad over time.

The Delco radio cassette I have (Blaupunkt 4-button cassette unit) needs a new optical sensor.
Moved to new thread https://www.fiero.nl/forum/Forum2/HTML/144287.html

[This message has been edited by fierosound (edited 09-04-2020).]

quote Originally posted by pmbrunelle: I can't imagine an ECM containing much bulk electrolytic capacitance. Probably contains largely ceramic class 2 dielectric, but the aging of that goes with log(time), so if it's stable now, the computer will probably continue to work for quite a while. Depends on what other parts could go bad over time.

OBD1 ECM has some caps but often doesn't matter and still dies...
Many old GM ECM die just from "paint" used to make them. The "paint" swells and break parts off the board.
Iffy solder joints can fail too. Example: ECM can't turn on FI because driver "transistor" and other things have barfed a joint.
Worse w/ Fiero mounting ECM poorly at GM vs. Most other old GM cars have ECM under the dash that allows a lot of air to cool them. See my Cave, ECM Heat

Newer ECM/PCM etc have surface mount caps etc and often dies.
Worse, many are mounted in the engine bay and cooks and dies sooner.