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Yamaha C-70 Control Problem

RebusCom

RebusCom

New Member
This is for the experienced C-70 folks. I very recently picked up one of these units that was supposedly "tested" as fully operational only to find that the front panel controls are stuck in phono mode. When trying to switch to any other mode like tuner, aux, etc., a relay click is heard but the phono lamp remains illuminated and it doesn't change modes. Is this the symptom typically seen with a faulty SW104 mentioned in this forum, or is that the relay I'm hearing (or both)?

Thanks in advance. BTW, I have a matching M-70 as well which appears to work fine. I'd love to get a working pair as they've been one of my favorites.

I assume a full restore would be the ideal option for the C-70. I'd like to hear recommendations/offers regarding techs willing to perform the operation. They're getting harder to find nowadays. PM me if you like. Thanks again.
 
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Sounds like what that switch usually does when they get sticky. It's not a very difficult fix, but there are other areas to address in these C70's usually to keep them running. Avionic is a Yamaha pro and has helped me with a few issues, including my C70. Good luck.
 
I pulled the cover and it is indeed a sticky SW104 bank. They try to actuate but don't, unless some help is provided. Looks like a clean and lube is needed. What's the best product to use on them?
 
RebusCom said:
What's the best product to use on them?
Click to expand...
Complete removal and disassembly and cleaning of each of the gummed up solenoids with alcohol . Then a very light relube with fresh white lithium.
 
Thanks in advance. BTW, I have a matching M-70 as well which appears to work fine. I'd love to get a working pair as they've been one of my favorites.

I assume a full restore would be the ideal option for the C-70. I'd like to hear recommendations/offers regarding techs willing to perform the operation. They're getting harder to find nowadays. PM me if you like. Thanks again.[/QUOTE]

Did you ever find a tech for your C-70?
 
No, I have not had the C-70 or M-70 rebuilt but did get the solenoids working without completely disassembling them. I am still interested in having a quality rebuild performed.
 
RebusCom said:
No, I have not had the C-70 or M-70 rebuilt but did get the solenoids working without completely disassembling them. I am still interested in having a quality rebuild performed.
Click to expand...
Hello. I am having the same issue with my Yamaha C-70, only it was after I used Detoxit Gold contact cleaner that my switch board became sticky. All of my sources were selected. The solenoids are operating but not disengaging as if the springs were stuck. I had to manually release them to select aux 1. My turntable will operate through Disk Direct which I can live with for now. I'm curious how you were able to get yours to operate as they should.
 
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