Adcom Channel Damage Help

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I was thinking of buying an Adcom amp. The seller says he accidentially shorted the positive & negative speaker leads from one channel. That channel doesn't work now.

I'd appreciate a general idea of what could have gotten blown. He says he hasn't opened the case. Does Adcom have internal fuses to protect against what happened or is it more likely something more serious is damaged.

I've built a few sets of speakers but have never tinkered inside an amp.

Any guidance and ideas would be very appreciated.
 
Ralph-- I have had 15 years of great listening with an Adcom GFA-555, Adcom GTP 400 pre-amp, Apogee Centaur Minor speakers, and Swiss Symo LS-5 SX speaker cabling. Although I generally tread very, very carefully around my equipment, I finally accidentally stepped on the speaker cable to the right channel about 3 weeks ago. The connectors simply pulled out of the right Apogee speaker; however, I have had no right channel at all since this occurred. I tested both speakers (both are fine), switched out interconnects and speaker cable, and alas, the right channel is still completely dead. This circumstance sounds somewhat similar to the story you received from the seller you described in your post.

I have almost no skill at all as regards any thoughts of carrying out a repair on my own, and I must admit that time constraints are even worse than my lack of skill..

I would be curious to know if it is worth attempting to locate the talent needed for the repair work or if it might be just as worthwhile replacing the amplifier.

Any thoughts?

Thanks.
 
Adcom Trouble?

Yes, there are fuses inside that Adcom.

Simply unplug it from the wall, find the correct size Allen driver (2.5MM I think) and remove the top.

You will see 2 fuses per side in the corners nearest the top and front of the unit. remove these and go looking for replacements at any auto parts, hardware, electronics store.

replace and be happy.

I purchased a 545II for $200 and put a .15 cent fuse in it and now I can't tell the difference between it and my $500 original.
 
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Hi agingaudionut,
Either send the unit to Adcom or call them so you can bring it to the nearest warranty depot. A good tech job is priceless, a bad one is more than a complete waste. Generally speaking, a shop that does lots of TV's is not a good choice.

A good tech will have this unit sounding at least as good as when it left the factory. And it will keep playing for years unless you kill it.

-Chris
 
Adcom Service

Don't mean to derail this thread too much. But has anyone heard of the health of Adcom these days. I know the owner of a big marketing firm in my area has stopped distributing Adcom because of quality control issue's. He thinks they maybe going out of business soon. I guess it was costing him more to distribute Adcom because of the replacement and repair of defective new product. I may be way off base here, about them going belly-up. I've always held Adcom in high regard and would be sad to see them leave the market. I'm sure repair of old as well as new would go on as usual.

I have a GFA-545 that's 20 years old and sounds as good today as it did when I bought it! My advice; get it repaired and you will be very happy!

Just wondering if anyone else has heard this recently about Adcom. Sorry if this is off topic too much.

Brock
 
Re: Adcom Trouble?

jasonva said:
Yes, there are fuses inside that Adcom.

Simply unplug it from the wall, find the correct size Allen driver (2.5MM I think) and remove the top.

You will see 2 fuses per side in the corners nearest the top and front of the unit. remove these and go looking for replacements at any auto parts, hardware, electronics store.

replace and be happy.

I purchased a 545II for $200 and put a .15 cent fuse in it and now I can't tell the difference between it and my $500 original.

I've shorted my Adcom GFA-545II twice now. Pulled the top off and replaced the fuse and it sounds just fine.

If the fuse looks unblown, pull it and measure it with a DMM. One time it happend, I did a visual and both fuses looked fine. I ended up pulling them both out and measuring them. Turned out one was in fact blown. I had to use a magnifying glass to see the break in the wire.
 
If you have shorted the speaker wires together, best case scenario is it needs a fuse replaced, most likely scenario is a couple of blown output devices which are not too hard to replace (if you know what you are doing)... worst case scenario.... well I will leave it at that.

In lower rail (545 etc) designs ( typically below +/-70 vdc) chances are fair that only a fuse is gone, in higher rail designs (like the 555) more likely that the outputs are shorted... exceptions notwithstanding.
 
I would like to thank everyone for the helpful posts and guidance.

As regards the details of the incident that led to the problem--- I am almost 100% sure that the speaker leads did not touch each other when they were accidentally pulled out, so this is apparently good news. I will certainly look into the straightforward possibility of a blown fuse once I get back into town and get home, and I'll post the results. If that doesn't work out, the Adcom web site lists 2 different retailers in my area who are supposedly Adcom dealers, and I would then pursue that route.

I would love to get that 555 working again, as I was enjoying it as much during year 15 as I did during year 1......

Thanks again..........
 
Adcom blown channel: follow-up

I would like to again thank everyone for their posts and suggestions. The following took place since I last posted:

1. After reading the posts here, I removed the top plate, and I did, in fact, find 2 blown fuses associated with the right channel.

2. I easily obtained replacement fuses and replaced. Still no right channel.

3. I searched the Adcom web site and found a high end retailer located about a 25-30 minute drive from home. I contacted the store, and I was told that they would be happy to help......

4. One month and many, many phone calls later, I was finally told that the amplifier was repaired. I was told that a "circuit board" and "other things" had to be replaced. When I pressed for a few more details ("like, uhhhhh, what other things?"), the response was "I don't know".

5. Before driving to the store and handing over a check for $325, I made it clear that I wanted this informed fellow to show me that the amp was working properly before I would pay him.

6. I drove to the store, and he did, in fact, have the amp connected to other components in one of their main listening rooms. He played something briefly, and it sounded great. I gave him his check.

7. I drove home, carefully reconnected the Symo cabling to my Apogee Centaur minors (with everything unplugged at the time), then plugged in the components, and connected the power. No right channel.......................

8. Before ever taking the Adcom out of my place to get repaired, I was absolutely sure I had gone through a variety of cable switching, etc. to be assured that I didn't have a bad piece of cable and that I had not damaged my speakers. All of that seemed to test out fine.......or at least I thought it did. Needless to say, after #7 above, I started second guessing myself............

9. Yesterday, I borrowed an old, unused Denon receiver from a friend. I used some old, never-used Monster Cable to connect the receiver to the Apogees. No right channel...................

10. I guess I better start searching for help with repair of a 15-year old Apogee Centaur Minor............... or maybe it's just time to start completely over when finances permit. :confused:
 
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Hi agingaudionut,

Did you try swapping the input leads, then the speaker leads?

I really don't like the sound of your repair. Did you get old parts back, or can you see inside where they worked on the unit? Unless they can provide details and parts, I'd have a talk with the folks at Adcom. PCB's are not available I don't think. Worst case is you paid $$$ for the amp to sit and they found there was nothing wrong with it. They had to charge you for them sitting on it for a month.

-Chris
 
Hi Anatech,

Thanks for your note back and recommendations. I was so fed up after testing my speakers with the borrowed Denon receiver that I just turned everything off and decided just to leave it be for a while......

As regards the establishment that allegedly did the Adcom repair--- needless to say, I would never go back there. There was a lot of delay, several never-returned phone calls, no clear cut explanation regarding what was found to be wrong, no return of the replaced parts. The store owner was more interested in spouting off about some new optical cabling he had for the low, low price of $1500/metered pair. After I saw the Adcom connected to components at his store, and he played it briefly, and it seemed to work fine, and then determining that I still had no right sided sound after using a different amp/pre-amp (the Denon that I borrowed.......), I have to admit concluding that I must have toasted BOTH the amp and the right speaker. There is always the possibility of a dead right channel in the borrowed receiver and/or damaged speaker cable (I used different speaker cable with the Denon than I used with the Adcom); however, the friend from whom I borrowed it felt sure that the receiver worked fine the last time he used it, and the standard Monster cable that I used was stored, never used, and appeared to have no obvious defects on close inspection.

Some next steps will be to try to find a couple of speakers to borrow to test my Adcom equipment. I should also mention that when I tested my Apogees with the borrowed Denon receiver, I simply used the tuner as the input; however, I should go back and make some additional speaker cable switches just to make sure.

Thanks again for your notes.
 
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Hi agingaudionut,

I was authorized Adcom service before selling my shop. I have a very deep distrust of store repairs. Their mark ups are normally well over 20% and they are more likely to mis-use a customer's trust. Always remember they are there to sell new gear, repairs are a problem. I bet they were hoping you would refuse the estimate and leave it there.

There were times that lead time exceeded a month, but we always informed the customer honestly about delays. We always returned all parts with real supportable documentation as to the nature of the repair and work performed. If I were you, I would contact Adcom about your experience as it sounds like you were abused. Request that Adcom gets back to you about who repaired your amp (outside shop?) and details. Do not leave this. Yes the amp was out of warranty, but you did take it to an Adcom dealer that they (Adcom) recommended.

This puts Adcom and the dealer at odds, but you are performing a valuable service to Adcom. They need to know what happens to an Adcom customer in the field.

Regards, Chris (another thing that makes me angry)
 
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