RCA 8TS30 Negative Image

[kvflyer]

Originally Posted by Electronic M

My approach is change papers, out of tolerance resistors and if it still has problems and they relate to stages with micas change the micas last.

This ^^^

[bandersen]

Originally Posted by Yamamaya42

I was told not to touch those mica caps when I did my FADA, as it would all but guarantee a IF alignment would be needed, but I did replace the 1500pf ones on the cathodes.

They are coupling caps and should not significantly affect the alignment. After finding bad ones in several 630TS, and 721TS sets I started replacing them more aggressively.
Those 1500pF caps are ceramic and very reliable. I'm surprised you needed to replace them.

[Yamamaya42]

Originally Posted by bandersen

They are coupling caps and should not significantly affect the alignment. After finding bad ones in several 630TS, and 721TS sets I started replacing them more aggressively.
Those 1500pF caps are ceramic and very reliable. I'm surprised you needed to replace them.

the set spent many years in musty damp basement before I got it, even after replacing the 150 ohm resistors on the IF string, (they were way out of tol) I was still having trouble getting the +135 to make it to the far end of the string to the 1st if and tuner, so i changed out the 1500pf caps, that brought up the bias significantly, I did not at the time, have a way to test them for leakage.

And as mentioned, the Mica ones are still in there.

[Yamamaya42]

It was THESE little buggers that caused me so much trouble in my FADA!



Not so much these, they seemed OK. and were left in!