Adcom GFA-585 Limited Edition Repair

I have an Adcom GFA-585 Limited Edition that needs repair. The Adcom repair folks told me that a cap leaked into a board. This causes the speakers to emit a terrible crackling sound when the amp is first fired up. If I let it warm up for an extended period, it will play without noise. As soon as it cools down, the crackling reappears. Adcom states that repair parts are no longer available.

This amp is one of my favorite pieces of gear and I cannot afford what it would cost to get something comparable.

If anyone knows where I can get this repaired, you will earn my unending gratitude.

Maybe I should offer a reward for information leading to the repair of this amp!
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Or an authorized warranty depot. A good one. It is unlikely that there is no sub for your caps. The leakage should be visible on the board, but I haven't heard of this as a specific fault or weakness. It is possible.

Too bad I'm in Canada, shipping is a supreme pain (border thing).

-Chris
 
Maybe I wasn't too clear on my initial post. It has been to Adcom for repair. When the cap leaked, the fluid got into a board and the board needs replacing. They state they no longer have the board to repair it.

Maybe someone knows of a source for this part or of an independent repair shop that can help.

I'll ship it anywhere if it can be fixed.
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi,
The board can be cleaned. If damaged it is not extremely dificult to recreate the board. Labour intensive.
The original board may need to be stripped for cleaning and for sure to use as a template.

I can do this but there must be someone closer who can. I don't like to deal with the border either.

-Chris
 
What I was told was that the board needed to be replaced. I don't know anything about circuit boards.

I'm sure if there was a way to repair a board, I could find someone in the area to do it. Just what kind of business would have this kind of skill? What industry should I be searching for?

In short, where do I start and where would I look?

I appreciate the answers to my question.
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi wilsonmw,
The board needs to be looked at. If the leakage isn't too bad, the area is stripped of parts and cleaned, then reassembled. This may include the entire PCB. If there is damage, the old board is stripped and used as a drilling guide to make a new PCB.

The process is pretty straight forward but may set you back $300.00 or so in labour and parts. The most important quality in your tech will be carefull, neat work

I have successfully rebuilt boards with holes burned in them, and copied obsolete boards that were water damaged (most foil corroded off). Not to mention ones burned in half or broken. It is possible to do a long lasting job.

-Chris
 

clem_o

Member
2005-06-14 6:34 am
Manila
If the amp still manages to operate, I'd hazard a guess that it can't be damaged that badly (yet). I agree with Chris' view that it should be possible to just clean out the board. It may not even be necessary to remove the parts in the affected area.

Soap and water does a very good job; however if you're not familiar with electronics I'd suggest not trying to do it yourself... (it's very easy to turn a potentiometer and not know its original setting)... BTW, the leaked stuff from the bad capacitor is corrosive, and will continue to damage your PCB more and more. Best you get it cleaned out asap.


Cheers!
 

ashok

Member
2002-06-06 4:43 am
3RS
Cleaning the board. I've done this before.
Two things to be careful about.
1. Any solvent used must not dissolve anything on board ( like plastic parts).
2. Most of the water must be removed quickly as it could be
absorbed by the board.

Make a mild soap solution ( I prefer dish washer liquid soap ) and dip the board in it and brush clean it with a long hair paint brush ( maybe 0.5 inches wide ) for a few minutes. Five minutes minutes should be enough I think. More , if the contaminating residue is dry - say 15 minutes or so.
Then wash away the soapy water well with distilled water.
Finally rinse the board with a mixture of pure isopropyl alcohol and distilled water. I use a 50 : 50 mixture.
The remaining water should come away quickly. Hand shake dry.
Dry the board with a hot air gun or in an 'OPEN' oven ( set at 100 deg C ). Monitor the drying process and DO NOT leave it in the oven without supervision.You cannot afford to overheat the components especially any electrolytic capacitors. The idea is to evaporate the water as soon as possible. Alternatively , dry it in a draft of air from a fan. This might be much safer.

I have overheated a board in an oven kept shut and lost it !
Cheers.
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi lordfoo,
Clem and Ashok have given very good advice. The danger is water trapped inside parts and under parts. Therefore, take your time with the drying process, be thorough. If you can take the bias pot off the board without moving the wiper, do it. May as well replace the electrolytic caps (all) when you are done. Sometimes the cleaning fluid will "wick" into the part and destroy it over time. You may want to leave the board out a day or two before continueing.

Any areas that show corrosion or fluid, at least release one leg of the part to clean around and inspect. Take a couple digital pictures up close before you start. Take your time with this and relax.

-Chris
 
wilsonmw said:
What I was told was that the board needed to be replaced. I don't know anything about circuit boards.

I'm sure if there was a way to repair a board, I could find someone in the area to do it. Just what kind of business would have this kind of skill? What industry should I be searching for?

In short, where do I start and where would I look?

I appreciate the answers to my question.

The CB can't be completely hosed or the amp wouldn't work.

Take a listen to anatech there. He's a pretty smart fellow.
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi Fearlessleader1,
If the copper is okay, the board can be rebuilt for sure. If it's just fluid, they will have to depopulate that section of the board and rebuild it after cleaning. It can be done. It will not be cheap though.

There has to be people close by that can do this for you.

-Chris
 
ADCOM repair advice

Hello !
Some weeks ago i repaired a pair of these big amps, the electrolytics lost fluid and destroyed some small signal semiconductors.
I checked and replaced all electrolytics and the killed semiconductors on the driver PCB.
Finally i had the problem with the conductive fluid (it produced large offset voltage )which was NOT completely removable with pure alcool, and replacement boards were not available here in germany. We decided to put the driver board (only this - not the whole amp) in the dish washer, after two washes the PCB was cleaned. This is no joke!!! Try it, but dry it also (not more than 50°C in the oven for some hours).

if you have further questions send me an email to info(add)schwindt-audio.de
 
anatech

I have the amp at the shop now at In House Service Company and he was going to rebuild the board when the problem of the conductivity with in the board came up. Cost *LOL* at this point I am already crying but replacement of this amp would be even more costly as I bought it about a year ago and it was $500 and I have $100 just in having it looked at. I could just find another amp like it for about the same money but it seems that rebuilding this board would still have to be done as it’s a age thing with these amps, so I would just have to send it out anyway back to the same people that its at now just so to make sure the this would not repeat with another. I am pretty sure I could get this board cleaned off to be reproduced if I had someone that would do it. Oh YA and be real grateful!!! I love this amp and just don’t want to give up on it.
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi Fearlessleader1,
I get Adcoms in, and used to do warranty on them. I have had to recreate various boards over time, and repair damage. This is on all makes that are worth repairing. Replacement boards are typically not stocked, so this is not abnormal.

If I can do it, there is someone close to you that can as well. There are good technicians around. You just have to look under rocks to find them sometimes.

Try and get someone local to you.

-Chris
 
Hi anatech

I wish that was true for me but I just moved here from Buffalo NY and finding anything here has been hard. The best tech I could find here told my I needed new caps for the power supply:rolleyes: So this time I had to send the amp to back NY so I could find anybody that had a clue:mad: So now at this point I have spent $100 just to find out that I have to spend $75 more just to get back my broken amp! Here I get the usual runaround and everyone will be glad to look at my amp and charge me another $50 to tell me they can't fix it :scratch:
 
spent 30 seconds more

hello !
while cleaning the board , i would spent half a minute more for readjusting the quiescent current. it is worth this.

and after cleaning procedure by dishwasher you have to dry it in the oven, best is some hours by less than 70 degree Celsius, not more !!!
Don´t close the oven completely !

best wishes
Murphy