Restoring an RCA CTC-10 "Wynnwood".

[Eric H]

Checked the tubes in the TV chassis tonight, there were nine bad ones, most had shorts, the 6AQ5 and the 6BK4 were weak, the one 6GH8 in the set checked good! The Sweep tubes (output and damper) checked OK but not as good as they could be so I'll replace them if I have spares.
There are a few tubes in the remote chassis I haven't checked yet because it's still in the cabinet in the garage.

[marty59]

Whenever you test a 6BK4 tinted like that you know it's gonna' check bad. Looks like some original's there too, that's quite a service life!

[holmesuser01]

Originally Posted by Eric H

Checked the tubes in the TV chassis tonight, there were nine bad ones, most had shorts, the 6AQ5 and the 6BK4 were weak, the one 6GH8 in the set checked good! The Sweep tubes (output and damper) checked OK but not as good as they could be so I'll replace them if I have spares.
There are a few tubes in the remote chassis I haven't checked yet because it's still in the cabinet in the garage.

That old 6BK4 will run forever. I've seen them almost black and they are still regulating.

6AQ5's running at 10-20% will still make sound.

I look forward to seeing a picture on this one. Mine is run about once a month, and looks decent on original caps, except for a couple of electrolytics. It will get a recap eventually.

[Charlie]

Originally Posted by holmesuser01

6AQ5's running at 10-20% will still make sound.

Amen! That particular tube always seems to be bullet proof.... even in the vertical circuits.

Perhaps all that dirt on the regulator will provide some extra shielding!