Hello, I've just joined and have been restoring a QRX 8001. I found it in a barn loft where it had been for at least ten years. It was dead with a blown fuse. Got it running through headphones with some distortion on the rear left and no output from the rear right by replacing fuse and removing two shorted output transistors. I re-pinned the switch board and recapped the entire unit and converted bulbs to LED. the rear right missing channel was traced to a chip on the quad board (HA 1328). At this point it sounded great through the headphones.
On to the outputs:
I've rebuilt the driver boards from a kit that included replacement of the fusible resistors, diodes, high quality caps, and transistors except for the drivers. It draws current (pulses) through my dim bulb tester and i cannot set the output voltage or bias current. The 46 and -46 volt supply is not reading correctly. I get -72 volts out of the rectifier D602 and 9 volts from D601.
My specific questions:
recommendations for 2638? Maybe a rebuild kit?
Are NTE280 and NTE281 suitable output replacements? I could not find matched pairs.
I'm taking a week away from this beast but any information would be most appreciated.
On to the outputs:
I've rebuilt the driver boards from a kit that included replacement of the fusible resistors, diodes, high quality caps, and transistors except for the drivers. It draws current (pulses) through my dim bulb tester and i cannot set the output voltage or bias current. The 46 and -46 volt supply is not reading correctly. I get -72 volts out of the rectifier D602 and 9 volts from D601.
My specific questions:
recommendations for 2638? Maybe a rebuild kit?
Are NTE280 and NTE281 suitable output replacements? I could not find matched pairs.
I'm taking a week away from this beast but any information would be most appreciated.
After all of the components I've replaced, I'm a bit embarrassed and not surprised.