[dbrown]

Need to know how to rebuild or replace BC Resistor in model 89 code 123. I am using a Rider schematic. Part #32 32 ohms and part #33 235 ohms. I have retired and trying to learn vintage radio repair. Thanks for your help.

[Radioroslyn]

Why do you think it needs to be replaced?
Terry

[Steve Davis]

Hi,

If the BC resistor is open, it can be replaced with separate resistors. If only one section is open, only that section need be replaced. I would unwrap the bad section, just to make sure it doesn't "heal" at a later time, then connect the new resistor to the lugs of the old one. Ten watt resistors should do it. Someone else may chime in on that.

Steve

[dbrown]

Why do you think it needs to be replaced?
Terry

Thanks for your reply. The B+ voltage was 475. The resistor was very rusted and the resistance would not read stable. When I tried to clean the resistor the wire fell apart.

[codefox1]

Agreed, if a section is open you can sub a 10 watt sand resistor dressed against the chassis and use the existing lugs as mounting terminals. But if there is a short to the chassis, or evidence ore arcing, drill the candohm out and replace all the sections. You can use one or both of the rivet holes to mount a terminal strip. Again, dress the replacements up against the chassis to help disperse heat.

Of course if there was a problem with this rather hardy component I would certainly suspect the filter capacitors, which you should replace before powering up again. Actually all the paper capacitors as well, and any other resistors much above spec.

[dbrown]

Thanks, I will try the 10 watt resistor.
Brown

[dbrown]

I am still working on Model 89. I have it working up to IF tube. Using signal generator I can hear signal at signal grid of IF tube but cannot hear signal at begining of 1st IF transformer#18. Could the compensating condenser #19 be the problem and how do I test it. I am using schematic dated July 15, 1934. Cannot hear signal at plate of 36 tube either.
Thanks for your help.