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Help with Adcom GFA555-II
Help with Adcom GFA555-II
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Old 18th November 2012, 02:47 PM   #1
kico is offline kico  United States
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Join Date: Apr 2010
Location: East Coast
Default Help with Adcom GFA555-II

I recently picked up an Adcom GFA555-II at a local yard sale in excellent physical condition, but only the right channel works correctly. I checked the fuses, and all are good and the correct rating for the channel rails at 7 amps. It does not blow any fuses on power up or during use and seems to have correct rail voltage +80v/-80v.

I do get a minimal and distorted signal from the left channel with the volume on my preamp turned way up beyond normal listening levels. The only damaged (burned out) component I found was a resistor (R-107) 3.9k on the input board which I replaced…no left channel improvement. Everything inside looks original, all Toshiba labeled outputs. The bias on the right channel is 10.5mV and stable; there is no reading on the left channel.

Where do I start looking for the problem?

Thanks all—I really appreciate your helping me to get this fixed.

Service manual link---http://akdatabase.org/AKview/albums/...%20Service.pdf
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Old 19th November 2012, 12:41 PM   #2
wahab is offline wahab  Algeria
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Join Date: Nov 2009
Location: algeria/france
Google trhrough DIY audio , there s so much Adcom GFA related threads
that you ll likely find one wich raison d etre is the same problem as yours.
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