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Help troubleshooting 144B
#1

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:
  • 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?


Messages In This Thread
Help troubleshooting 144B - by Nathan Slingerland - 01-14-2017, 08:44 PM
RE: Help troubleshooting 144B - by Radioroslyn - 01-14-2017, 09:13 PM
RE: Help troubleshooting 144B - by Radioroslyn - 01-15-2017, 12:47 AM



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