HELP ! My sx-1010 has lost his voice !

[ALIBERT]

New member of AK from PARIS (FRANCE) I was the proud owner of a beautiful sx1010 receiver that I bought a few weeks ago on EBAY. I say "was" because after a few days of good service, the right channel began to crack very noisily (even with the power in the 0 position) and now it is completely out of use (I mean the right channel, because the left one is still working).
I want to repair it with a friend of mine, who is very clever in electronics, but he told me that the schematics of the amplifier would be of great help for him.
So, if someone among you has got it, and I'm sure someone has got one, it would be very kind from him to send it to me. I don't need the entire service manual, but just the schematics of the amplifier section.
Thank you in advance for your help, but I'm sure you understand me : I can't stand looking at this beautiful PIONEER blue light without hearing at the same time his powerful sound !
JPA

 

[Kamakiri]

I have the schematics in paper form, but don't have a scanner......Fax might be possible.....?

 

[EchoWars]

The problem is dirt in the controls and switches. Pay especially close attention to the 'push' switches on the front panel.


Here's a blurry pic of where you need to squirt cleaner to take care of the push switches. I think you can get the idea.

I use only DeOxit, but I hear that it is tough to find in Europe.

 

[agger]

Yep, thats one posibility. Try to jiggle around with the switches, including the tape monitors. Does the sound come back?
If not, it could also be the common desease on pioneer receivers of this age: Crackling sound could come from the small predriver transistors (on the SX-737 they are 2SC726). If one of those guys now died totaly, this could be the reason for your defect.

 

[ALIBERT]

Thank you for your help. I give you my FAX number : 33 1 55 95 18 91. Actually, from the USA I think that you must do 011 33 1 55 95 18 91. I let you know wether it has worked or not.
Anyway thank you again.
JPA
PS : I must find a nickname like anybody else on AK.

 

[ALIBERT]

Thank you very much for your help. As I have already looked at the switches and especially the tape monitors ones, I 'll look at the small predriver transistors. It might be the answer.
JPA

 

[ALIBERT]

Thank you I am going to look at the push switches but first I must disassembly the front panel and that doesnot look very easy. At that time I have onlyremoved the wooden top cover.
Anyways, thanks a lot!
JPA

 

[EchoWars]

Don't go farking around with the electronics when it's not necessary. There isn't a separate protection circuit for each channel. If you had some transistor give up on one channel, the protection shuts 'em both down.

99 times out of 100, if you lose only one channel, it's a dirty switch. I've likely worked on more SX-1010's than anything else, and this is very very common.

It is much easier to pull off the front panel and clean the switches than to get in there are start a wild goose chase replacing components.

The 1010 has main-in/pre-out jacks. If it is a switch issue, you should be able to connect a source component directly to the 'main-in' jacks and hear both channels (please make sure this component that you connect to the main-in jacks has a volume control, and it is turned down to start, otherwise you are likely to blow your speakers or wake the baby that lives 3 blocks away...)

 

[Strawman]

Alibert

Listen to Echo, he is the Master Jedi of this stuff. If you go in there and "Fark" it all up, You will infact get nickname, Good luck, always go with the basics before your clever friend fries your amp.