01-14-2017, 07:44 PM
I previously restored a 144B (Code 125) in April of 2016. Everything was recapped and it was working well then but I haven't played it a while. When I plugged it in today it is not working.
The set powers up - and if not tuned to a station I hear normal sounding static. However, as soon as I tune into a station the volume cuts out and the sound is garbled. Static will return if I tune away from the station after a couple of seconds. Here's a video:
http://vid1072.photobucket.com/albums/w3...5z4gep.mp4
Things I've checked so far:
Not finding anything obvious I measured voltages and compared to the service bulletin. I set my variac to be 115V when loaded with the radio. My measurements (digital voltmeter) are in blue:
I wasn't sure where I was supposed to measure the "P-K" voltage (**) listed under the 80 tube (no pins named that). Same problem with the "SG-K" voltage (*) for the 6A7 tube.
Do these voltage seem right? I kind of expected the measured values to be higher than the service bulletin values since I'm measuring with a modern DMM.
Any suggestions on what to check / try next?
The set powers up - and if not tuned to a station I hear normal sounding static. However, as soon as I tune into a station the volume cuts out and the sound is garbled. Static will return if I tune away from the station after a couple of seconds. Here's a video:
http://vid1072.photobucket.com/albums/w3...5z4gep.mp4
Things I've checked so far:
- Tested tubes on TV-7 - measure good
- Swapped in alternate for each tube - these tubes also measure good - but no effect
- Checked resistor values - measure good
Not finding anything obvious I measured voltages and compared to the service bulletin. I set my variac to be 115V when loaded with the radio. My measurements (digital voltmeter) are in blue:
I wasn't sure where I was supposed to measure the "P-K" voltage (**) listed under the 80 tube (no pins named that). Same problem with the "SG-K" voltage (*) for the 6A7 tube.
Do these voltage seem right? I kind of expected the measured values to be higher than the service bulletin values since I'm measuring with a modern DMM.
Any suggestions on what to check / try next?
