ADCOM GFA-585 Is it possible for it not to blow up - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th January 2008, 09:34 PM   #1
mobay is offline mobay  United States
diyAudio Member
 
Join Date: Jan 2008
Default ADCOM GFA-585 Is it possible for it not to blow up

I bought recently a used ADCOM GFA-585 amp. I've had no issues with it whatsoever. However I learned yesterday that I may have a time bomb on my hands. By that I mean the famous GFA-585 leaking cap issue.

Mine has a serial number of 0463 ( early model I guess ) .

My question is to the experts here:

1) was the failure rate 100% on these amps ?( i.e. just a matter of time )

2) are there any warning signs to show imminent failure?.

3) Could the unit have had the caps replaced by the previous owner ?( what should I look for if I take off the cover?)

Thanks for your patience.

Randy
  Reply With Quote
Old 31st January 2008, 01:35 AM   #2
diyAudio Member
 
Join Date: Dec 2006
Send a message via Yahoo to ben62670
Hey Randy.
I would definetely take off the cover, and change those caps.
Once they leak on the input boards you have major problems. I know. I have about 80hrs between research, and work on mine.
Feel free to contact me. Phone is a lot easier than PM's Also check your DC offset.


Ben
  Reply With Quote
Old 31st January 2008, 03:49 AM   #3
mobay is offline mobay  United States
diyAudio Member
 
Join Date: Jan 2008
I plan to and hope beyond hope that I do not see ELNA caps.. although I kind of doubt it. With me delivering it , the authorised ADCOM service center in Virginia will charge about $230 for the "repair"

If it was'nt for the damn bias adjustment and just a straight cap replacement I'd tackle it myself, I have limited experience or equipment for diagnostic work however. Wrote ADCOM who sent me a detailed .PDF describing the condition ( mainly geared to a 565 mono block) . They basically were VERY helpful in telling me that a problem existed.

I cannot believe that the 565 and 585 could have such a defect and that the failure rate is 100%. Unbelievable.

Once again, mine works perfectly, no thump, no crackling, nothing.., which makes it all the more annoying to have to shell out almost what I paid for the amp ( $300 ) to repair it.

Oh well..., lemme stop whining. Somewhere , somehow there's a person out there with one that has never failed. I'm led to believe by others however, that a scenario like that is like finding a 24 year old virgin in New York or Los Angeles!!

Thanks for the offer, I appreciated it
  Reply With Quote
Old 31st January 2008, 04:05 AM   #4
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi mobay,
Yes, 100%. Sorry to confirm that.

Right now it's a straight capacitor change unless you smell something nasty while desoldering the old parts. Replace all the caps on the board. I am wishing you luck on this.

Would you do me a big favour please mobay? I have not seen the document you are talking about. Is it possible to email it to me? I'll send you my email address.

BTW, the caps are a good brand, but there was a run of bad ones. The electrolyte is the problem. Elna caps are a top brand of capacitor.

Also, I have seen units that have not failed - yet. It might be a temperature related thing. Don't guess, just get it looked after.

-Chris
__________________
"Just because you can, doesn't mean you should" my Wife
  Reply With Quote
Old 31st January 2008, 05:45 AM   #5
mobay is offline mobay  United States
diyAudio Member
 
Join Date: Jan 2008
You should have the .pdf now.

The pictures are indeed very helpful. Wish I could do the damn repair myself as the capacitors seems small an access to the board appears to be easy.
  Reply With Quote
Old 31st January 2008, 02:43 PM   #6
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi mobay,
I do, and thank you.

I feel that PDF is not entirely accurate and have commented to tech support at Adcom. You have my concerns via my rely to the email. Use your common sense would be my main comment.

The PDF states that those PCBs are "paper", or phenolic type. This is not true, it is an epoxy PCB. It does seem to soak up this evil stuff though. Also, atmospheric contaminants were blamed for the leakage. This is also not the case if you think about it. My belief is that it is an electrolyte issue, the same one that plagued computer products. Elna is a good brand of capacitor normally.

The other comments are easily figured out if you read and look where they are coming from. The Ebayer's comments are a bit self serving and designed to elevate the service above normal attempts. While the service is good as stated, there is excessive work being done and some parts being replaced under the guise of improving the performance. This is also not the case. The original components used are very good. No improvement will be heard or measured with these "upgrades". The flake factor has surfaced.

-Chris
__________________
"Just because you can, doesn't mean you should" my Wife
  Reply With Quote
Old 31st January 2008, 05:58 PM   #7
mobay is offline mobay  United States
diyAudio Member
 
Join Date: Jan 2008
Default The .PDF file on leaking Caps for ADCOM GFA-585

Chris,

As is usual for you , your providing a great service for those of us who own a ADCOM GFA-565 , 585 or maybe even more.

The .PDF file was sent to me by a "sales Engineer" ( yep! that was his title ) at ADCOM's headquarters in AZ. This was after I asked them if the problem was a case of 100% failure of all the units made or just a few. His "help" was to attach the .pdf and then suggest that I get the unit fixed.

I also asked if there were any warning signs to indicate imminent failure , and did not get anything from this " Engineer"

Now a lot of readers will say " why bring up this dead horse"? Well..., a lot of people will get these amps hook them up to expensive speakers , and then have the amp burn them out or God forbid even worse ( fire ). When I bought my amp, I had no idea that there was such a serious and devastating problem.

I know that what I'll say next will not make me popular with ADCOM owners, but just like car manufacturers , ADCOM needs to "fess up" and assume SOME sort of responsibility for this.

My son's 1997 Chrysler Sebring got warranty work done (10 years later ) on a lower control arm for a problem that was discovered a lont time ago. If I had a pair of expensive speakers burnt out because of a amplifier with a known ( by the MFG) defect , you can bet I'll be pissed off.

I still need to know what are the warning signs or will the caps just shoot their wad over the circuit board , and then "whammo!
your speakers are toast!"

Anyone have any real life experiences to relate with this problem, as far as how bad it got for them?

thanks
  Reply With Quote
Old 31st January 2008, 06:39 PM   #8
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Randy,
Most often there are no warning signs that anyone would notice. Sometimes there may be some low frequency noise, or some excessive on / off thumps. The problem is that it's not until complete failure, or truly excessive offset occurs that the average person would stop using the equipment. That is human nature (from my own observations over the years).

Since Adcom was purchased and completely restructured, I would not expect them to warranty any old products for any problems. I'm just happy they didn't go "poof!" gone. The other issue is that this fault is not Adcom's fault at all. They purchased good quality capacitors and used them properly. It is not a design flaw, nor is it the result of buying from the cheapest vendor. The damage is the result (from what I can tell) of a dishonest company that sold defective electrolyte for use in capacitor manufacture. Perhaps Elna was remiss in it's supply chain management. The current Adcom company had no knowledge or warning of the previous events and is really a completely different company.

I'm not really trying to defend Adcom, but I had a working relationship with the original firm and I knew what their intentions and design direction was. Believe me when I say that this would have been horrifying to them. Completely unavoidable and unintentional. I also know that this information doesn't help you, except that it is now the devil you know rather than a surprise speaker cook-off.

-Chris
__________________
"Just because you can, doesn't mean you should" my Wife
  Reply With Quote
Old 31st January 2008, 08:11 PM   #9
mobay is offline mobay  United States
diyAudio Member
 
Join Date: Jan 2008
Default OK Chris will lay this one to rest

No need to waste electrons. I'll just have to bite the bullet and send the unit to be fixed. Wish I could have simply replaced the capacitors as that does not look too hard.

But, if I have to then do diagnostic work afterwards, I cannot
take the chance of blowing the amp up.

Thanks again Chris
Randy
  Reply With Quote
Old 31st January 2008, 08:40 PM   #10
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Randy,
Why not have a look? If the caps have not leaked yet, you should be able to do the job.

-Chris

Edit: Look for soggy bottoms on the caps. If you touch the bottom with your hot soldering iron, you can sample the odor to you can test the PCB. IF all you smell is hot rubber - GREAT!!!
__________________
"Just because you can, doesn't mean you should" my Wife
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
NAD fuses, slow blow or fast blow? AllCaster Solid State 3 25th October 2009 06:11 PM
Adcom GFA-535 Blow fuses after connected to MG-Is vacs2000 Solid State 0 26th February 2009 07:35 PM
Blow up once, Blow up twice and Blow up somemore S.C Chip Amps 14 6th March 2005 12:09 AM
Will This Blow Up? Trout Tubes / Valves 8 6th February 2005 12:52 PM
Adcom GFA-585 went bad - calling Adcom experts hangguy Solid State 14 24th December 2004 08:09 PM


New To Site? Need Help?

All times are GMT. The time now is 02:24 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2