Sansui G-9700

anti-doom

Well-Known Member
Just got a Sansui G-9700 off CL for $100. It seems to be in working condition. Sound is coming from both channels but left channel is weaker then the right. Sound is loud increasing following the volume but not clear. Any thought or suggestion. Thanks a lot.
 
You got a SCROE! on that.
Should be a great receiver once it's working properly.
 
A thorough deoxit and if that doesnt work then try again and do everything because gremlins like that can hide anywhere
Good luck
 
I've had one for 34 years or so. Great receiver. I'm sure once you get the bugs out you'll be very happy with it. - dan
 
I am still looking for the culprit. Have been cleaning all the pots so many times but still get distortion. Probably need to recap it. Thanks
 
Since the receiver has distortion, should I look at the output transistors first or look at the driver boards? Thanks
 
Driver board has a couple fusistors on it, check them to see if they are still within spec and not blown.
 
Narrow down the preamp section works fine. Only the power amp section has problem. I think I need to check the driver boards and the power transistors. Any idea?
 
I pulled out the 2 fuse resistors R17 and R20 from the board and sure enough they are dead. So I know that is the problem, I will buy new ones and replace them and will post the result today. Thanks for the input.
 
Do both boards, the other one isn't far behind. Use 1/4 watt metal film- I believe they are 1/4 w, the parts list will confirm.
 
Yes they are 150 ohm 1/4 w and I will do both boards. Can not wait to hear this monster receiver when done. Will keep updated. thanks
 
Yes they are 150 ohm 1/4 w and I will do both boards. Can not wait to hear this monster receiver when done. Will keep updated. thanks

Be aware that you ABSOLUTELY need to reset the bias on this amp as soon as you power it up after replacing the fuse resistors. I would be powering it up on a DBT and once stabilized, I'd set the bias for 1 mv for now, and zero out the DC offset and then power it up direct, let it idle for an hour to stabilize. Do a final setting with the the bias at 5mV and the DC at 10 mV or lower.

The G-9700 is a great receiver with a fast and powerful amp, however it can be unstable due to poor thermal compensation.
 
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Bgears,
Thanks for DBT. I just finished replacing the fuse resistors on both boards. Now the amp works fine and give me the best sound ever. But it run only about 3-5 minutes then the Safely Operate light is blinking and keep blinking. When the light blinks, the amp does not have sound. I think something is not right on the driver board but do not know exactly what it is. Please help.
 
Bgears,
Thanks for DBT. I just finished replacing the fuse resistors on both boards. Now the amp works fine and give me the best sound ever. But it run only about 3-5 minutes then the Safely Operate light is blinking and keep blinking. When the light blinks, the amp does not have sound. I think something is not right on the driver board but do not know exactly what it is. Please help.

No shortcuts unless you want to see the magic smoke. Go back to post #16 and make the settings and report back. Do take a calculated and analytical approach to this repair or suffer the consequences.
 
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