02-22-2023, 08:31 PM
Hi all,
I’m hoping someone can give me an idea how to troubleshoot this problem.
I started to align my 38-116 last night. This is one mentioned in a previous post (I was so busy at work I had to stop for a while and I’m just getting back into things). I finished the recap, and it was playing well about 2 years ago when I got busy at work and stopped. It played well a few days ago as well but It did have an issue with the automatic tuning, however. The mute function didn't work and interfered with reception, cutting it off and on unless I held it in place manually. So after a while of getting nowhere, I changed the tuning dial mechanism with a spare I had. The issue with the mute was gone. I thought that may be the problem, but it wasn’t although the tuning dial mechanism now works as it should. I could select stations before but now it’s stuck on 570 am and only if I probe the grid cap on the second IF tube with a wire or my finger, otherwise it is silent. I deoxed all the controls, tube bases and grid caps as well.
All the voltages at the tube bases look good and match the schematic within about 10%.
I also don't get any reception at all when I attach a wire/probe to the antenna post or probe the RF, Mixer or detector tubes along the tuning capacitor. These circuits seem to be inoperative even though tubes are nice and warm.
Someone also put a ground from pin 1 on the 6K7 RF tube (6U7 called for in the schematic but the 6K7 is supposed to be a substitute).
I checked the wire would resistors and they are ok. Otherwise, I'd like suggestions where else to start, I have an old signal injector I need to check for operation in case it can help troubleshoot.
Thanks for your help,
Steve
I’m hoping someone can give me an idea how to troubleshoot this problem.
I started to align my 38-116 last night. This is one mentioned in a previous post (I was so busy at work I had to stop for a while and I’m just getting back into things). I finished the recap, and it was playing well about 2 years ago when I got busy at work and stopped. It played well a few days ago as well but It did have an issue with the automatic tuning, however. The mute function didn't work and interfered with reception, cutting it off and on unless I held it in place manually. So after a while of getting nowhere, I changed the tuning dial mechanism with a spare I had. The issue with the mute was gone. I thought that may be the problem, but it wasn’t although the tuning dial mechanism now works as it should. I could select stations before but now it’s stuck on 570 am and only if I probe the grid cap on the second IF tube with a wire or my finger, otherwise it is silent. I deoxed all the controls, tube bases and grid caps as well.
All the voltages at the tube bases look good and match the schematic within about 10%.
I also don't get any reception at all when I attach a wire/probe to the antenna post or probe the RF, Mixer or detector tubes along the tuning capacitor. These circuits seem to be inoperative even though tubes are nice and warm.
Someone also put a ground from pin 1 on the 6K7 RF tube (6U7 called for in the schematic but the 6K7 is supposed to be a substitute).
I checked the wire would resistors and they are ok. Otherwise, I'd like suggestions where else to start, I have an old signal injector I need to check for operation in case it can help troubleshoot.
Thanks for your help,
Steve
