Hello All,
I replaced all the paper and electrolytic capacitors in this radio. My first test resulted in a very hot resistor between the two capacitors in the power supply. When connected B+ is 18 volts. Disconnected it's over 170. So I know that the power supply is working fine. This is the 6 volt radio with the built in speaker but it's very similar to the 12v models that also appeared in 1950 (see Sams AR-2), only this model's schematic wasn't released until 1958. Model number is 7258865 (SAMS 419 page 2 of "the Photofact Servicer"Nov 1, 1958). This voltage first connects to pin 4 on both of the 6V6s, this is the screen grid. No, I'm not measuring the cathode resistor by accident, on pin 8. There is really a load on the B+ line somewhere.
I unplugged both 6V6s and the 6AV6 and there is still a 415 ohm load. I guess I'm going to have spend a lot of "fun" time troubleshooting this set to find it, unless someone has some suggestions that will make this process take less time. If I find the problem, quickly I'll let everyone know what it is or was.

Thanks,

Dave

Possible short in the output transformer?

Peter,
Does the output transformer connect there? The output transformer connects to the plates. When B+ is disconnected there is no load. B++ is connected to the output transformer and to the plate. I don't see how this affects B+. How would it?

Thanks,

Dave
:Possible short in the output transformer?
:

Peter,
Even though I have sleeving on my capacitors, one of the leads was touching a terminal on an IF transformer. I moved the capacitor away and, like magic, the radio is working electronically.
It only scans a little bit and seems to get stuck, so I have to shut off the radio to release the relay. I hope it's just dirt on the contacts. Otherwise these have always been very frustrating to work on. This radio is signal-seeker only with no manual tuning.
The 415 ohm load on the B+ line is gone.

Thanks,

Dave

:Peter,
: Does the output transformer connect there? The output transformer connects to the plates. When B+ is disconnected there is no load. B++ is connected to the output transformer and to the plate. I don't see how this affects B+. How would it?
:
:Thanks,
:
:Dave
::Possible short in the output transformer?
::
:

OK Dave glad you found the short.
I didn't have a schematic so I was only tossing out one possible direction to investigate.

Peter,
Even though I have sleeving on my capacitors, one of the leads was touching a terminal on an IF transformer. I moved the capacitor away and, like magic, the radio is working electronically.
It only scans a little bit and seems to get stuck, so I have to shut off the radio to release the relay. I hope it's just dirt on the contacts. Otherwise these have always been very frustrating to work on. This radio is signal-seeker only with no manual tuning.
The 415 ohm load on the B+ line is gone.

Thanks,

Dave

:Peter,
: Does the output transformer connect there? The output transformer connects to the plates. When B+ is disconnected there is no load. B++ is connected to the output transformer and to the plate. I don't see how this affects B+. How would it?
:
:Thanks,
:
:Dave
::Possible short in the output transformer?
::
:

Dave, Don't think it's the relay causing the problem. It's mechanical moving parts. They always are dry, and get stuck. Clean everything that moves, slides, and turns. Use a little dielectric grease after.

Warren,
This radio works perfectly mechanically. It now also stops at every station and returns at the end of the band. It was an electronic problem. Same as the first electronic problem. I found the offending wire and eliminated it and everything works fine. The mechanical section doesn't stick at all whatsoever.
This radio works great now.

Thanks,

Dave
:Dave, Don't think it's the relay causing the problem. It's mechanical moving parts. They always are dry, and get stuck. Clean everything that moves, slides, and turns. Use a little dielectric grease after.
: