We are getting progress
At your suggestions I pulled the mixer and measured the cathode voltage. Now down to 32v. I then pulled the IF and refitted the Mixer. Cathode now at 96v. Both out 0v. With just the IF valve in and vCath at 32v I could inject a signal at IF grid (topcap) and hear a demodulated tone. So this brings us back to the mixer. The hexode coil (L8) measures about 2ohms. The screen grid R measures correct at 15Kand its decoupler (C9) is a new replacement. I put in a 0.1 as opposed to the origonal of 0.01. Reasoning that as its decoupling the value should not be that critical. Maybe i was wrong.
Dead valve?
Malcolm