Help repairing car stereos: Delco 90's CD & tape player

[vipe155]

This looks like it, though the decimal point is much harder to discern on mine.
https://wellgainelectronics.com/resonators/34990-murata-csa120mt.html
All I have is a multimeter and a simple logic probe.

I also found a couple of leaking surface mount caps on the CD mech board.

 

[Harald Kapp]

I also found a couple of leaking surface mount caps on the CD mech board.

Pictures?
If they are leaking, that can cause any sort of trouble. On the other hand, often big components are glued to the pcb to prevent them from falling off due to vibration. The glue may in some cases look very similar to a leaking capacitor. The caps in your image imho show no leaks. Could you indicate where you suspect leakage?

 

[vipe155]

Pictures?
If they are leaking, that can cause any sort of trouble. On the other hand, often big components are glued to the pcb to prevent them from falling off due to vibration. The glue may in some cases look very similar to a leaking capacitor. The caps in your image imho show no leaks. Could you indicate where you suspect leakage?

I'm surprised you don't think there is an issue with the 100uf 6V caps in the above picture. Unlike all the other caps on the board, the solder points have a brown/tan colored rough buildup on those two caps. I'm also wondering about that residue between the 47uf and the left 100uf.

 

[vipe155]

Yep, it's a ceramic resonator only a 2-pin variety, not the 3-pin I linked to above. They are readily available BUT they are also pretty reliable too so I'd be surprised if it's a dud or off frequency. The only way you can tell, without recourse to a frequency meter or oscilloscope, is to replace it though. Being as cheap as they are it's a lot easier than sourcing a 'scope!

I'm not finding this part or an equivalent easily or cheaply. Where I would usually buy components, like Digikey and Mouser here in the U.S., don't have them. All I've found here is an ebay listing wanting $15 for 25 of them. I'm not sure if it's worth it just to blindly replace the part, unless that really is a strong possibility on why the display is modulating in brightness.

 

[Harald Kapp]

Apart from that spot next to C618 that doesn't look very bad for me. I've seen much worse. I thought this might be flux residue.
It won't be muh effort to remove these caps, clean the board and solder new caps onto it. With luck you've solved the problem.

 

[vipe155]

Apart from that spot next to C618 that doesn't look very bad for me. I've seen much worse. I thought this might be flux residue.
It won't be muh effort to remove these caps, clean the board and solder new caps onto it. With luck you've solved the problem.

I just ordered a few Panasonic 100uf 16V surface mount caps, and I'm going to clean the area up before those get here. I'll cross my fingers that this works, but I'm not betting on it.

Thanks for all the help I've gotten on this thread so far.

 

[vipe155]

Well, I replaced the two caps but no change. Not that I expected it, but one can hope.

Basically, this whole thing frustrates me because there are service manuals for these units, but you can't easily find them. They pop up on eBay or similar sites. Getting a hard copy is a needle in a haystack thing. I really need a 93-95 one, but right now all I can find are 1980s manuals that may or may not help/crossover. I don't even know who to ask to find the service manuals, but if I had one I think I could fix these units.

 

[kellys_eye]

Can only sympathise with your plight. Service information is getting harder to access by the day. The citing of IPR (Intellectual Property Rights) is the bane of engineers everywhere.

I admit to actually PAYING to download service data in the past - something I abhor since this is simply people taking advantage of something that should, by law, be accessible to everytone free of charge - but only because I'm a stubborn old git! Fortunately it wasn't expensive (around $5 IIRC) but it still stuck in my craw!

That said, many faults are fixable if you have the experience and the equipment necessary to locate them - two factors that aren't in your complete arsenal of attack sadly. I'd love to have a go for you but location doesn't help either. Keep at it.