Pioneer SA-9800 ( advice needed on pre-amp repair )

[Soundlab1]

Hi All



I'm fairly new to the AK forum but needed a little technical advice on troubleshooting a fault that I had picked up on my Pioneer SA9800 amp recently.


The left channel plays at a lower volume as compared to the right channel without any distortion.The tone controls , filters , balance, volume ..etc....works flawlessly although at a low volume compared to the R-channel. I've even swapped over RCA cables and the problem remains the same.I've tried several different inputs ( Tuner , tape 1 , tape 2 ) , and still the same thing.......

I know that the problem is within the pre-amp section of the SA-9800 as I have connected my Pioneer C90 pre-amp into the power-amp in on the Pioneer Sa-9800 and perfect L & R channels .

So my question is .... What could the actual problem be within the pre-amp stage ??

Any suggestions or advice would be much appreciated !!!

Thanks.....

Best Regards

 

[century tek]

Deox all the pots and switches. You might be surprised.

 

[petehall347]

have you tried pre out to another amp ?

 

[Soundlab1]

Yes , I've tried Deoxit on the pots & switches but that didn't help either........will try connecting the pre-out to another power amp tomorrow to see what happens..


Will let you know how that goes Petehall347.

Thanks guys

 

[petehall347]

i dont expect any different but worth a try in case .

 

[Soundlab1]

Hi Guys


Just a report back on my issue.........

After a total removal of the pre-amp and tone control assemblies of my Pioneer Sa-9800 , I finally discovered my problem .


You guys wouldn't believe this but on close inspection of the volume control assembly , I noticed a cold solder joint on one of the pins of the flat ribbon cable.This flat ribbon cable (white) connects the Volume Assy to one of the Tone Control assemblies.

Continuity testing using my DMM confirmed that the one pin on the cable indeed had a BAD connection.So I re-soldered the entire ribbon cable on either sides (Just to make extra safe )........Hooked the amp up afterwards and the left channel starting working flawlessly !!!............


Thanks to you guys that I also got to Deoxit my beloved amp in the process of troubleshooting.


Thanks once again for your time and good advice rendered.................Cheers & Keep that vintage audio loving going !!!

 

[petehall347]

well done