One of my TR-4s has the following problem:
Malfuncions after 5 minutes
RF gain in any position
Audio gain in any postion
When you switch to XCW and tune up, upon going back to SSB the control tube
will not let the tansceiver go back to rec. The B+ is not on the transmitter,
but the plate meter is reading .1 which indicates the power supply bias is set
properly.
If you switch the band sw back and forth to other bands, it will correct
itself and start receiving again.
I use PTT and have the vox control full clockwise and anti-vox full counter
clockwise.
I bought a new brumfield/potter enclosed relay and that did not help. I have
changed the 6EV7 control tube with a nos tube.
I am now thinking it is the time constant network going to the grid of the
6ev7 which contains a series 1K resistor going to the grid and a series of bias
resistors and diodes from the primary side of the grid resistor to antivox
circuit and a series of high ohm grid bias resistors. I am about ready to start
changing the time constant resistors and caps one at a time.
Has anyone out there had this problem ?73's Boyd W0BUW
