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?

Can someone point to the right tube/area to check for this problem?
I'll have to get some tubes to swap out but don't want to get all at
this time.

Tks to all in advance

best holidays,
Tom