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Sansui G-7700 Phono issue

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Dennis S

New Member
Hi,
I just got a G-7700 that I bought off of ebay. Of course the ad said works perfectly.
Well, it got here, and I went thru it and found that the left channel on both phono inputs are
putting out very little signal, if any at all. Everything else works fine. One thing that did happen was, while fiddling with the TT connectors, the receiver made a loud buzz, like that of a guitar cable being unplugged from a guitar with the amp still on. Then it went into protection mode. I had to turn it off, and back on again to be able to play it. Are the phono inputs all on one board, and not incorporated into the main board. Is this going to be a real pain in the butt?
I really don't want to send this back, as is my right, since I got it on ebay. I got it for a good price, and have been looking for one, since I sold mine almost 40 years ago. Any help would be appreciated.
Thanks!
 
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These units have terribly cheap and unreliable switches, Tape MON 1 and 2, + the Source switch are always culprits, tone defeat switch is another one...
The function switch itself is notoriously unreliable as well.

I have a G7700 I have owned for over 10 years, I use it in my Lab to listen to whilst I work, every now and then especially if it hasn't been on for a while, I need to run through and exercise al, the switches, its not uncommon to turn it on and have one side not working...

Now this is even after I have been through and cleaned all the switches, cleaning them works for a while but the problem always returns if the switches are not regularly used.

So I would start there with all the switches, the electronics side of things is pretty reliable, but you would want to plan to fully update the unit with new caps, some transistors, relay, trimmers.
There is corrosive glue used in these units and you don't want to leave it too long before you get into a resto.

The G7700 is a very nice receiver, great powerful, clean and clear sounding unit, exceptional tuner when its aligned properly....I enjoy mine...
 
I have it apart right now. The switch that chooses sources, phono, aux, AM/FM isnt what I expected. I imagine I could spray that with some deoxit. Someone sprayed the phono connectors with something I can only describe as WD-40. I need to clean that out, probably with a light spritz of brake clean. It's very safe for PC boards.either that or just spray it off with deoxit as well. I am thinking tightening the positive poles on the jacks might help as well. One thing I need to find is the schematics for it. Thanks for your input. I bought a G-7700 new back in 1979 when I was in the service. $360 bucks at the PX. I always wanted to find another, as I had sold that one. :-)
 
Dennis S said:
The switch that chooses sources, phono, aux, AM/FM isnt what I expected
Click to expand...
No its a very long slide switch, you can however get the D5 into it, I think you can get it from one end. Then there may be some very small holes in the top where you can get some in too.

Dennis S said:
Someone sprayed the phono connectors with something I can only describe as WD-40. I need to clean that out, probably with a light spritz of brake clean.
Click to expand...
Dont use brake clean in there, use a non residue cleaner, CRC make one, I used it for cleaning tuning gangs. Brake clean is way too harsh, it has carbon-tetrachloride in it. Too brutal.

You can get the schematics and complete service manual from HiFi engine, you have to sign up, its free, then you can download the manual.
 
Good news! I traced down the lines with a continuity tester. I got signal at the switch, but none out of the switch, so, DeOxit to the rescue. It worked great! So now I have a great sounding receiver that plays vinyl, like I needed. Thanks for your help!
 
Dennis S said:
Good news! I traced down the lines with a continuity tester. I got signal at the switch, but none out of the switch, so, DeOxit to the rescue. It worked great! So now I have a great sounding receiver that plays vinyl, like I needed. Thanks for your help!
Click to expand...
Well there you go that was easy!! Nice one...enjoy some nice sounds!!


I wouldn't leave it too long to do a restoration on it, there are issues which will rear their ugly heads.......
 
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