1938 Radio Information

[Tom Beaver]

Does anyone have a copy of the circuit diagram for a Cadillac Standard Radio for 1938, which I assume is a Wells-Gardner radio, that they could share?  I am in the process of trying to re-cap the thing and have run into some parts that I can't identify.  Also I am having trouble reconciling markings on the resistors with the values measured with an ohm meter.  Any help would be appreciated.

Tom Beaver

[Warren Rauch #4286]

  I don't see on the diagram I have who the maker was. It is Cadillac # 7232502. This is a 5 tube model, it says it is the 1938 Standard Model. The copy I have is from a book ( John F Rider). Is this what you need? Warren

[Tom Beaver]

Warren,

Thank you for the reply.  Yes that is the part number that is written on the tag inside the radio I have.  I don't know how hard it would be to copy the diagram but it sounds like it is just what I need.

Tom Beaver

[bcroe]

Good luck on the radio, I have some 1938 stuff here too.  Besides caps, the higher value
resistors tend to drift up, though the values aren't critical.  Does it use a 6 pin vibrator,
or a rectifier tube?  Bruce Roe

[Tom Beaver]

Bruce,

The color code on the resistors seems to have drifted along with the resistance, It seems red and orange are indistinguishable so I need something that gives what the values should be.  The vibrator sits in a 6 pin socket but the device itself has only 5 pins.  I don't know what that signifies but I thought I would take a run at getting the thing to work if I can.

Tom Beaver

[Warren Rauch #4286]

 I'll send it off on monday. Warren

[Tom Beaver]

Warren,

Thank you very much.  I have hope now of actually getting it to work.

Tom Beaver

[bcroe]

If the 1938 radio is in decent mechanical shape, it certainly is possible
to get it working.  All the parts should be available, or a more modern
substitute.  A basic vibrator only needs 3 pins, but was mounted on a
standard 4 pin base.  This converts the bat DC to AC, so the transformer
can step up the voltage.  Then it must be rectified to high voltage DC. 
Some radios used a rectifier tube, others used a couple more contacts
on the vibrator to switch to the proper side of the transformer output,
at the proper time.  I know you can buy 4 pin vibrators, and electronic
equivalents that plug in.  Not so sure about the 6 pin type. 

With the polarized caps replaced, tubes removed, the vibrator should
generate some +200V to +300V to be available for the tubes.  If not,
I'd see about fixing the power section first.  One way out, is use a 4
pin vibrator (test with a spare 4 pin socket) and a couple pretty high
voltage silicon diodes.  There is likely a rather high voltage cap at the
trans output, that needs to be replaced; it limits voltage spikes. 

Bruce Roe

[Tom Beaver]

Bruce,
Thank you for the information and suggestions.  The radio seems to be in fairly good mechanical shape except for the speaker so I plan on working on replacing all of the capacitors and those resistors that seem to be out of bounds and see where I get to.  The vibrator may be ok, and if not, one of the people in the local car club says he has some spares so I should be in good shape there.

Thanks again.

Tom Beaver

[bcroe]

Good Luck, keep us informed.  I'm CLC  # 14630   bcroe@juno.com   Bruce Roe