The AM Forum

I recently acquired a Globe King 500B, does anyone know the difference between the 500B and the 500C? Also need to replace the VFO dial cover....has anyone made replacements for the VFO cover?

I think the C had a ceramic coil form?
I had one a long time ago.
I used the RF deck for a while, but gave up on it and put all the parts in the junk box or sold them off.

For one thing the B model used a relay to bypass the secondary of the mod transformer for CW the C model used a ceramic switch.  The B model used a rely to apply primary power to the Low voltage supply and the C model used a switch.  The B model read modulator current by metering the HV from the ps to the 811A tube plates, the C model metered the CT of the 811 tube filament transformer (a real worthy modification for the no suffix, A and B models)

Some books showed the final RF tube in the B to be a 4-250AX whereas the C called for the 4-400.  The circuits were mostly the same maybe a few component changes, maybe around the keying tube.  Not a lot of difference at all.

When you say, Dial Cover, I assume you want one for the VFO????
http://jmpalmquist.home.comcast.net/~jmpalmquist/Inventory.htm

Hi Joe,
          I believe also in addition to the differences already listed, the C model was the only one to have the built in VFO on the P/S deck. At least that is the way it appears in the manuals I have for them.
          I'm in process of rebuilding a C P/S deck right at the moment. Hopefully, I'll have it completed by this weekend.

73, Phil   

Both the B and C had the built in VFO.  The transition between the B and C was a bit fuzzy.  I had a 500B, but it had the same decks and control circuits as the C, although the 4-400 stage coil form was not ceramic.  I'm guessing that WRL made changes over time, and occasionally updated the model number after they hit some critical mass of changes.  The biggest visual difference if you weren't looking closely at the control layouts on the PS/MOD decks was the black border on the bottom edge of the meters.

Grant NQ5T

Also be careful of any manual you have.  They are/can be full of mistakes for the unit your have.  I have the original manual shipped with my A model and it has several errors in it.