Globe King Model Differences

[WB6NVH]

In 53 years of hamming I never saw a Globe King in person, yet in the past three months I have bought two of them in central California that were less than $ 100.

The latest one was in an estate internet only auction conducted by laymen who knew nothing about ham gear and most everything sold for peanuts.  This one is a very clean Globe King 500, but here is my question.  Since Leo didn't silk screen the model numbers onto the front panels, how do you tell the difference between a 500B and a 500C?

I know the 500B has a 4-250 PA while the 500C has a 4-400 (?) (Yet my 500C manual shows a 6156 which is a 4-250!) and apparently the 500C has TVI shielding that the 500B doesn't.

How can I tell which suffix GK 500 I have?

EDIT: Unloaded it today.  This one has markings for SSB on the rear apron and has 5514's as the modulators, chassis so marked. There is a stock perforated TVI box around the whole PA deck.  I am thinking 500C at this point.

EDIT II:  This is going to make me one of those guys who answers his own question in a thread.  After cleanup and removal of stickers I see that the RF deck says "500 A."  Luckily I found a message on here from the previous (now SK) owner explaining what this is (!) once I figured out what his callsign was.  He says is is a 500A RF deck with 500C modulator and HV PS + VFO.  Hence the confusion. It seems there were a lot of running changes and one person's 500A RF deck can look a lot different from someone else's depending upon the production date.

[WD4LUR]

Geoff,

Yes, as you mentioned, I've also heard there were a lot of mid stream changes that weren't documented in the manual. I have a 500A that has a 6AG7 oscillator. The chassis is marker for those tubes, yet my 500A manual lists a 6V6 for the oscillator. My RF deck serial number is 966 and the front panel is silk screened "Model 500A" below the multi-meter. This front panel definitely looks to be original.
Also, I think WRL started installing the perforated shielding on the RF deck with the 500A. Mine has it and the old WRL ads for the 500A talks about the shielding.

Then my Modulator chassis has 5514's and is marked that way. Although the schematic shows it should be 811's.

I'm guessing there were a lot of parts left over from previous models that made there way into newer versions just to use up existing inventory.

Dan

[Jim, W5JO]

There are a lot of mistakes in the manuals, so be careful.  I think it is the 500B manual that has the modulator diagram with the pin numbers of the 6AL5 compressor mis labeled.  That is one mistake I can think of offhand.  I have what is known to be a 500A.  The original purchaser gave it to me which included the manual shipped with it.

The modulators tubes are marked 5514 on the chassis but it has 811A modulators.  To be sure, measure the filament voltage, mine was 6 volt.  The 5514 is a 7.5 volt filament tube.  Some A models have 4-400 marked on the RF deck but had 4-250s in there and vice versa.  No one knows if previous owners changed them.  Mine is marked 4-250 but was shipped with a 4-400.