Adcom GFP55 preamp/ no output relay click after power on.
- Thread starter Dmahon
- Start date
Register to hide this ad
RVT1K
Super Member
No direct experience with that unit but..
The first thing I would do is check the coil in the relay to verify there is continuity. if the coil is open, the relay needs to be replaced. If the coil has continuity, I would verify there is voltage at the coil.
Continuity and voltage points to the relay being stuck and probably needing to be replaced.
No voltage on the coil points upstream to something like a transistor used to operate the coil.
Do you have a schematic?
The first thing I would do is check the coil in the relay to verify there is continuity. if the coil is open, the relay needs to be replaced. If the coil has continuity, I would verify there is voltage at the coil.
Continuity and voltage points to the relay being stuck and probably needing to be replaced.
No voltage on the coil points upstream to something like a transistor used to operate the coil.
Do you have a schematic?
I found a schematic using meta AI but it’s such bad quality that it’s illegible. I just got the preamp from a buddy and haven’t had a chance to open it up. Figured I would save myself some legwork and see if anyone has had this exact problem. I’m guessing there must be an RC timer circuit running the 4 second delay to the relay. I know Adcom is notorious for failed capacitors and given its age I’m guessing that’s the case here.
RVT1K
Super Member
Although I fully understand the necessity, I have always found relays to be one of the least reliable items on a pcb.
There were quite a few boards -over two product lines- at my old job that had many, many relays -usually for scaling of signals- and they were a regular point of failure. To make matters worse, they were often mercury-whetted contacts and they were getting very hard to find.
Although the bad capacitor issue was real, I believe it was mostly limited to the GFA-565. That certainly does not eliminate the potential for a bad cap(s) in your unit but, based on my experience, I would suspect the relay before anything else.
There were quite a few boards -over two product lines- at my old job that had many, many relays -usually for scaling of signals- and they were a regular point of failure. To make matters worse, they were often mercury-whetted contacts and they were getting very hard to find.
Although the bad capacitor issue was real, I believe it was mostly limited to the GFA-565. That certainly does not eliminate the potential for a bad cap(s) in your unit but, based on my experience, I would suspect the relay before anything else.
