SA-9800 no sound just A/C hump

[TBL_HK]

I just got an SA-9800 at a thrift store, 6 knobs missing but otherwise good cosmetically. The thing is it just had no output, and the right channel wazs full of hump noise.

Pioneer gurus any idea if I should throw this one out or is it worth repairing? I can use a solder gun but have no idea about circuitry.

Help pls.

 

[EchoWars]

I gots no experiance with this one (and no prints)....anyone else?

 

[bully]

It was a TOTL unit in 1979-81. 100 wpc and a MSRP $750. Pioneers had a very good sound. I think it would be worth it to get it back to working condition.
Of course, how much you want to spend only you know.

 

[siamac]

Look at the backside. are there the two Jumper to connect the Pre-Amp with the Power-Amp??
The SA-9800 was Pioneer´s TOP OF THE LINE amp.
Try to buy a not working cheap Pioneer Amp from 1979/80 (SA-5800,6800,7800,8800, 508,608,708) to use the knobs from that amp! :yes:

 

[foetusized]

I have a user's manual for the SA-9800 but no service manual. I picked it up from Terry Dewickt today; he adjusted it and replaced some broken RCA jacks but didn't make any major repairs.

I just PM'd Terry, but I'll ask here too. He adjusted the bias on the amp because it was running hot, according to this thread. Wish I'd noticed it earlier, but when I brought into the house after driving home, I noticed that the SA-9800 and the TX-9800 tuner were both set on the back to 110V. Is this why the bias was off? Should I reset it to 120V after the adjustments that Terry made while it was set wrong? -- Foe

 

[crooner]

There shoudn't be much difference in 120V. I would reset the voltage and be with it.

 

[foetusized]

I figure so too, but can afford to be cautious and wait a little & be sure -- Foe

 

[crooner]

I figure, if he adjusted the unit for cooler operation at 110V, it will be even more on 120V. However, if idle current is too low you can get into crossover distortion. Perhaps Terry or Echowars could enlighten us on this.

 

[Pioneer727]

I would set it back to 120v check this thread by EW.

http://audiokarma.org/forums/showthread.php?t=32565

As far as the DC offset and Bias I would have it checked again just to be sure.

Ron

 

[foetusized]

As far as the DC offset and Bias I would have it checked again just to be sure.

I'd take it back to Knoxville but that's a 200 mile round trip, and it took me far too long to find a day to go down and pick them up. I would like to use them in the meantime. I could attempt to measure them myself, but I'd need to go get a multimeter and then figure out what to do with it.

PS: TBL_HK, sorry to hijack your thread, but if you can't guess, I really like my SA-9800 and have gone to some trouble to "get it right" -- Foe

 

[Pioneer727]

Have you read this thread.

http://audiokarma.org/forums/showthread.php?t=5634

Ron

 

[foetusized]

I have read that thread. Figuring out how to adjust the DC offset, and to measure and adjust the bias, would be more of a problem. I'd need someone to lead me through it. I would think that changing the voltage setting would change the bias more than the DC offset -- Foe

 

[Pioneer727]

Do you have a service manual on it? If so you may find someone here who also has a manual that can walk you thru it.Doing the DC offset is not bad but when doing the bias you must be vary carefull. Waring If you are unsure about doing the bias dont do it.

Ron

 

[EchoWars]

Set it to 120V and forget it. It isn't that sensitive, and Pioneer amps typically have a lot of breathing room anyway.

 

[foetusized]

Groovy! Thanks -- Foe

 

[TBL_HK]

Look at the backside. are there the two Jumper to connect the Pre-Amp with the Power-Amp??
The SA-9800 was Pioneer´s TOP OF THE LINE amp.
Try to buy a not working cheap Pioneer Amp from 1979/80 (SA-5800,6800,7800,8800, 508,608,708) to use the knobs from that amp! :yes:

I have a way of temp fixing the knobs - six 1-dollar knobs for time being, until I can cannabalize some 4 origjnal ones.

And yes the pre/amp jumpers are in, no fuse broken, and all the parts are there. (While doing a search in this forum, a msg from Italy said he'd got some parts missing on one SA-9800 he bid "as is".)

Any further ideas on how I should check before spending all the dollars? I'm willing to spend US$200 total to get it to work, mostly by getting the parts and DIY fixes of course.