Need advice on TR-4 repair
 

Thanks for taking time to read this.

My friend has a TR-4, which has an xmit trouble.

I can set the bias current to100ma, as per the manual, with no problem.

All tubes check OK. Receive is OK. I can peak the receive signal with the RF
TUNE control.

However, when I change to CW mode and I close the key and raise the XMTR
GAIN, the plate current doesn't move. (Yes, I'm using the "X" position on
the sideband switch).

The antenna is OK: I checked it with a noise bridge, so there's a proper
load.

Additional questions:

1. Should the Jones jack on the underside of the chassis have a shorting
plug in it? This rig doesn't. Assuming the jack is to connect an RV-4, if
the TR-4 was used with an RV-4, does it need a plug to work without the
RV-4?
2. Does the TR-4 generate CW with a tone oscillator or by unbalancing the
modulator?
3. Are replacement relays and/or switches available?

All suggestions welcome.

73, Bill

(Filter noise from my signal for direct replies)