QRX Service question

[Lewish]

I recently scored a QRX 5001 because I am in love with Sansui Quad. My tech is very talented but we can't understand an issue that happens with one channel not playing at full volume. When the unit is in stereo both channels are crystal clear and loud. When it switches to 4 channel with the QS synth mode the front left channel is 'ghost' like, and this is intermittent. It will be fixed and working and then stops working. Has anyone else had this happen. He's gone over all of the caps and the board and tested everything and it checks out and he can't identify what is causing the problem.

 

[petehall347]

the switches can and do get corroded ... time for deoxit

 

[sKiZo]

Yup ... switches, usually the pushbuttons used to select modes.

Easy test is to cycle modes and see if the problem goes away. Sometimes just rocking the selected button a bit can bring back a problem channel. Not to forget, Sansui uses a hybrid switch with all the electronics to the rear, so you do have to pop the top to clean them.

 

[LBPete]

Start by giving all the controls a good cleaning. Every knob, push button or lever has a switch or a pot behind it. Almost any one of them can be causing this problem. Get a can of Deoxit D5 and spray it into each of these controls. You need to get it inside the control and often it takes some disassembly to get access to an appropriate opening on the control.

Please post the serial number for the database. Click on the link in my signature block.

- Pete

 

[kevzep]

Also you really have to hope someone wasn't in the QS syth with the "golden screwdriver" making it "better"....
Very hard to bring it back without the right gear and procedure....

 

[N8Nagel]

I have the same problem with my 7001, and it's the 4 channel switches, they need more Deoxit than I gave them. I just haven't got to it yet. Try cycling the 2/4 channel mode switches a few times and see if that sorts it. Or if you have it apart just deoxit that whole assembly.