TJM wrote:
I'm a fairly new owner to the Drake line...

Having a small problem with a tr4-c and was hoping someone could send me
in the right direction.

After TX (cw) when relay releases, the RX sounds some times muted but
still there, the S-meter will rise up the scale to about 40+ and the rx
freq is off a bit (like on the wrong sideband)

If I re-Key, all will return to normal...this problem will happen about
50% of the time... looks like relay is fine), but more like the mute
curcuit is hanging...??? AGC?

Why do you say that it looks like the relay is fine? Have you tested
its contacts? Have you looked at its contacts? Just because it goes
kachunk doesn't mean it is doing its job. Every symptom you have described
is classic for T/R relay contact problems.

The contacts on T/R relays in tube radios often get corroded, smoky and
intermittent. The first trick is to rub a piece of paper soaked in 91%
isopropyl alcohol between each and every pair of contacts. operate the
relay manually so that the contacts close on the paper strip. Keep doing
this with fresh paper until the paper comes out clean. If the paper
tears, the contact is pitted, and will need to be burnished. Burnishing
is done with a piece of hardened sheet steel that has been ground on
a course grinding wheel to make scratches that are like a fine file. You
use it like a fine file.

Do not ever use emery paper, or sandpaper of any kind, on the contacts
of a relay. Don't use a file either.

-Chuck