QRX-9001 weak in 4 channel mode

[ezed1]

Hi everyone, I am new to this forum. I have a pretty nice collection of quad equipment, including a QRX-7001, Lafayette SQ-W, JVC CDD-5, and QRX-4500.

I recenty acquired an ailing Sansui QRX-9001 and have a few questions:

1) My receiver sounds good in 2 -channel mode but is weak in any of the 4 channels modes, basically unusable in these modes. What types of things can cause this? Can a blown amp caused by Channel operation in the (Power x 2) cause this? I have also heard that the Power X 2 relay can develop bad contacts and cause weakness in 4 channel mode. Just hoping to get some guidance as to the first places to look.

2) Where is the location of the infamous bad pass-through joints. I should probably rectify this problem. Could these connections gone bad cause my problem?

PS: My F-2088 and F-2087 decoder boards are not sick as I plugged these into my QRX-7001 and they work just fine. AUX mode in 4 channels doesn't work for squat.

Any advice welcome except "you're stupid Dan". My wife could tell me that, she has to live with me

Thanks

Dan

 

[MidiMagic]

If it is in power X2 mode when you are trying to listen to quad, it will be weak, because the speakers are out of phase with each other.

 

[ezed1]

Mine sounds really weak when it is not in 2X mode. This makes me wonder if the 2X relay is stuck. HMMMM.......

 

[Trnsfmr]

Hi,
Practically all the problems in 4 ch mode are caused by the pass throughs on the 2632 board, which is the one with all the pushbuttons on it. The only way to fix it is to disassemble the front panel to free up this board, and then re-pin all the pass throughs on the board. It is the only double sided board in the unit, and like a lot of double sided boards made in the 70's, the pass throughs, where the top connects to the bottom, are not reliable. I don't think it is very likely to be the relay.

I have a complete explanation of how to do it, with pictures, on my website

http://www.qrxrestore.com/

Sad to say, but this problem is the bane of the 9001.

 

[ezed1]

Thanks, you're the best. I really appreciate the advice and the link, this helps a lot.

After I finish recapping my QRX-7001 I will dive in. The 7001 (which sounds more beautiful with each board I restore) is teaching me a lot and getting me ready to take on the 9001 beast!

Dan

Hi,
Practically all the problems in 4 ch mode are caused by the pass throughs on the 2632 board, which is the one with all the pushbuttons on it. The only way to fix it is to disassemble the front panel to free up this board, and then re-pin all the pass throughs on the board. It is the only double sided board in the unit, and like a lot of double sided boards made in the 70's, the pass throughs, where the top connects to the bottom, are not reliable. I don't think it is very likely to be the relay.

I have a complete explanation of how to do it, with pictures, on my website

http://www.qrxrestore.com/

Sad to say, but this problem is the bane of the 9001.