Quad 44 preamp no sound in left side

[jollyrogernl]

quad 44 preamp no soun in left side

My quad amp 44 pre amp & 405 main amp, in stereo no left hand side sounds, but in mono both sides, anyone have any ideas what needs fixing

 

[commsysman]

Whe you say 'mono', do you mean you select mono mode on your preamp with a front-panel switch?

If both channels work that way, it is clearly not the power amplifier at fault.

It is probably something in the switching or early stages of your preamp, but signal tracing with a scope or meter is going to have to be done to isolate it.

 

[anatech]

Hi jollyrogernl,
Arrr matey! There be bad solder joints on the main PCB in the 44. Resolder all the leads from one side of the board to the other. There may be other issues but I can't remember all of the service note off hand.

-Chris

 

[Nigel Goodwin]

I repaired one the other year, the fault was electrolytics in the preamp, they had leaked electrolyte and corroded the PCB tracks. Cleaning the board, replacing the electrolytics, and repairing the damaged tracks cured it.

 

[jollyrogernl]

Thanks Matey

Avast me matey,
Tanks a million dubloons for yer welcome advise
Till we sail again,

Ta ta

 

[anatech]

Hey Nigel,
Thanks for refreshing my memory. I think there was also something about changing chips, or defective chips.

Old memories.

-Chris

 

[Zombie]

There's a 44 service manual on the 'quadhifi' group at www.yahoogroups.com
If it works in mono and not in stereo, it might be some dead 4066 switches...

 

[anatech]

Hi Zombie,
Now that makes sense. I believe they were replacing 4066 with 4966. That's the same chip pinout but a higher voltage rating. Could be wrong, but something was tugging at my mind.

-Chris

 

[jollyrogernl]

quad 44

Thanks Guys
Thats great info,