RCA 9TC240 Alignment...The start of my education (I hope!)

[bandersen]

Load plus regulation should keep the voltages at 20 and -6.3, but we suspect something may be drawing too much current and throwing the voltage off.

-6.3 to -3.7 isn't that big a difference and I would expect the circuits to keep working to some extent.

[Chris K]

I don't know if this adds anything to the troubleshooting but the 20V line is reading 23.5V on this input lead and the -6.3 input lead is reading essentially 0.

[Penthode]

Yeah I believe that container holds the hybrid output amplifier. I looks as if it may be the Achilles heel. Check the link to the guy that reconstructed and made a replacement. There is a lot of useful information there.

Also, if you look at the diagram for the output amp, the -6.3v is only switched in at the +20dBu attenuator setting. I believe to get better linearity at the high level setting.

[Chris K]

OK will do...Bob mentioned checking some of the test points on my scope and report what shows up. I'm at the bench with the bottom off.

[Chris K]

Sent an email to Dasaro to see if there's any chance he'd make one. We'll see.

[Chris K]

YOU'VE GOT TO BE KIDDING ME? A BROKEN SOLDER JOINT?

This can't be it

[Chris K]

Nope...didn't change a thing. I think I'm going to button this up and wait for the one that's on schedule to arrive Monday. A blown fuse and a broken solder lead in the suspected problem zone...both repaired and nothing. That's about as much as my electronic hopes can stand.

[Chris K]

Looks like the new purchase 8001a is arriving today. When it does I’ll go through it and make sure all is well. For the alignment, I’m going to start a new thread. This one has pleasantly meandered all over the place.

[Penthode]

Hopefully you will resolve the issue with the faulty generator.
It looks as if the hybrid amp is faulty on this one. To confirm you could try some more tests. Also we would be curious the reply you may receive in response to your request for the new replacement.

[Chris K]

He was very prompt and kind in his response but he said what you had suggested earlier that the transistors to build it were no longer available