[IMEP]

I was just listening to my 1989 vintage Adcom, when it just quit outputting sound. The display still works and the transport still seems to be working. Just no sound out of both outputs (fixed & variable). I took the cover off and found several electrolytics that appear to have leaked. The leaked material is hard, so I assume that they did not just begin leaking today. See photos below.

Anywho:
Is it probable the electrolytics failed from age? Nothing appears to have been overheated.

What are the chances that replacing the caps and cleaning the board will solve my problem?

What do you guys think I should do? I really like the player and would hate to throw in the towel.

 

[stereth]

Any way to desolder one or two of them and hook them up to a LCR meter?

How many look like that? It might only cost a recoverable $10-15 to put new ones in and try it out.

 

[IMEP]

Quote:

Originally Posted by stereth How many look like that? It might only cost a recoverable $10-15 to put new ones in and try it out.

Thanks for the reply stereth
That's what I was thinking.

I'm wondering what caused them to fail and if I need to look at anything else that may have been damaged. Will the ooz that leaked out and across other component leads hurt anything? Does anyone have any thoughts?

 

[taylor]

I've taken apart plenty of vintage gear, and that does not look like leakage.

On every one i've taken apart, there has been some kind of glue around the caps. In newer ones it's stuff from a hot glue gun, on all my pre-1990 gear it's been a brownish stuff that looks a lot like the stuff around your caps. Might not be leaking.

 

[Demolition]

Quote:

Originally Posted by IMEP I'm wondering what caused them to fail and if I need to look at anything else that may have been damaged. Will the ooz that leaked out and across other component leads hurt anything? Does anyone have any thoughts?

Usually, the failure can be traced to the electrolyte breaking down due to aging (i.e. years of use). The chemical structure changes and it begins to ooze or leak out of the metal canister. It's somewhat similar to what's been happening recently with the rash of electrolytic cap failures on computer motherboards. However, in the case of the motherboards, the failures occur rapidly (in a matter of months, in some cases) and the cause is a buildup of hydrogen inside the metal canister due to a chemical imbalance in the electrolyte. A possible end result is that the caps fail catastrophically by exploding and/or catching on fire. Most computer troubleshooting sites recommend to desolder the defective caps and replace them with quality caps.

That's what you'll have to do in your Adcom CD player, as stereth mentioned earlier.

As for the leaked-out electrolyte... if you clean up the board with a bit of anhydrous isopropyl alcohol, then it should be as good as new.

D.

 

[Glassman]

Quote:

Originally Posted by taylor I've taken apart plenty of vintage gear, and that does not look like leakage. On every one i've taken apart, there has been some kind of glue around the caps. In newer ones it's stuff from a hot glue gun, on all my pre-1990 gear it's been a brownish stuff that looks a lot like the stuff around your caps. Might not be leaking.

exactly.. sometimes you can see clear wax or something like that around parts, especially computer power supplies.. in the old days the material was like on your pics..

 

[IMEP]

Quote:

Originally Posted by Glassman exactly.. sometimes you can see clear wax or something like that around parts, especially computer power supplies.. in the old days the material was like on your pics..

Wow! It's just that the material looks so haphazardly spread out around the caps. I was initially thinking my problem was the caps failing due to a bad voltage regulator or something.
Does anyone else have any experience with old Adcom CD players that could confirm the material is just some sort of glue?

Thanks for all the input guys!

 

[Jesse Galliers]

I don't see how that could be leakage given the fact that in your second to last picture the compound is centered around a solid state component.

 

[tdownes111]

Quote:

Originally Posted by Jesse Galliers I don't see how that could be leakage given the fact that in your second to last picture the compound is centered around a solid state component.

The "goo" you see in the pictures is a glue/mastic designed to stabilize the components to protect from physical (shock) damage during shipping & handling.

I have a similar problem with the audio output on my GCD 575. I still get sound, but it's VERY faint, so I have a fault somewhere in the amplification stages of the CD player. If anyone has experience fixing it I'd love to hear about it.

 

[Super-Gonzo]

Quote:

Originally Posted by IMEP Does anyone else have any experience with old Adcom CD players that could confirm the material is just some sort of glue?

Yeah, I used to have a 575 and it had the same gunk around the caps... it worked fine (most of the time.)

My humble advice is to check the simple stuff first, like the output rca solder joints and any other signal path wire past the dac.

It's usually the mechanical stuff that busts first... the circuitry on this unit should last a good long while... these were made in the late 80's/early 90's right? That's not all that old.

 

[logotrikes]

Hi all, and IMEP,
 
Just joined this forum and thread since I too have an old but venerable GCD575 (1989) and have become interested in the idea of replacing the op amps with something a bit newer. I've ordered a pair of BB OPA627's with this in mind. The brown stuff around some caps inside of mine is similar to yours, so similar in fact that I thought you had mistakenly taken pics of the inside of my amp instead of yours LOL. I was a little concerned, but from scouring the forums, the brown crap appears to be benign glue.
 
I know very little about electronics so replacing the op amps with sockets first ( to enable op amp rolling should I have a mind) will be about the limit of the mischief I would inflict on the player. Improvements to electronic equipment has a touch of a "holy grail quest" about it; one can never know if one has attained maximum sonic benefit and so the search can become never ending. I don't think I would have the resolve or expertise to attempt much beyond very basic join-the-dots type alterations, and besides, speakers are my thing.
 
Still, reading these forums allows me a peak at what can be done. As in all forums of any discipline, there are some really knowledgable folks on this one, and it's a real pleasure to read some of the threads...
 
Cheers, Martin
Quote:

I was just listening to my 1989 vintage Adcom, when it just quit outputting sound. The display still works and the transport still seems to be working. Just no sound out of both outputs (fixed & variable). I took the cover off and found several electrolytics that appear to have leaked. The leaked material is hard, so I assume that they did not just begin leaking today. See photos below.Anywho:Is it probable the electrolytics failed from age? Nothing appears to have been overheated.What are the chances that replacing the caps and cleaning the board will solve my problem?What do you guys think I should do? I really like the player and would hate to throw in the towel.

 

 

[Pars]

^ You may want to rethink that. The OP275s (from memory) are only used as buffers. The actual I/V opamp per se in this is an Adcom-designed single inline pin affair over on the right side of the board, near the DAC chip. I wound up doing a discrete I/V stage for my brother's 575.