QUAD 34 help needed

[lmunasi]

New user to diyaudio and would appreciate some help. I picked up a QUAD 34 control amp that needs work. Here is the story:

SN on unit is 8966. The unit does not want to power up. I have checked the fuse and the transformer. The green LED (D33) lights up but nothing else. The unit appears to be in original condition without any mods. I realize that these have had problems with some of the electrolytic capacitors. I intend to change the OP amps once I figure out what the problem is. I do not have a service manual for this unit.

Any help in troubleshooting would be greatly appreciated.

Thanks,

 

[poynton]

Email Quad in the UK.

If you explain the problem, they will help even if only to email / fax / post the circuit.

Andy

 

[Jan Dupont]

I have had a 34 for many years. Bought it as original, but did a heavy mod on it.

It sounds very strange that the D33 will light up, and the amp still won't start up

Here you have the schematic

Rob Flain from Quad has been a great help to me....

 

[poynton]

The regulator may be dead IC21 or the opamp IC23 (provides the ground 0v )
You will have to probe with a meter.

Andy

 

[lmunasi]

Thanks for the reply and the schematic Andy and Jan. I will email Quad for help. Shall keep you posted of what I learn.

Lochi