Replacing Filament Transformer with NOS Thordarson
 

1953 or 1954 Philco with wrong chassis, but the correct Sams for the chassis is 227-10.

Split chassis. i think the filament transformer was replaced as the part number is wrong. I can find nothing about that part number online. Anyway it has always gotten hot. I think a couple years ago I trouble shot it and narrowed it down to a problem with that transformer. Im betting it was for a lower amp model and thats why it gets hot.

Forward to the present, I found a NOS Thordarson 21F12 filament transformer, a 10 amp model, the correct sub. No paperwork was included.

The one I removed had 4 wires. I can see that 2 were primary and 2 were filament. My new one has 5 wires. On my new one Im assuming (please tell me if Im wrong) that the 2 black wires are primary. On the other side of the tranny are 3 wires. 2 outer are solid green and the center one is green striped. So which ones do I use? Thanks!

You can verify with a resistance check but the striped one will be the secondary center tap so use the 2 solid green and insulate the striped one so it does not touch anything.

Thanks Tim!

Correct, the black wires are clearly primary, and before you set yourself up for any nasty surprises, you can always power it up out of circuit and measure the output

the more i think about it, the more i believe that you must be VERY SURE and careful before hooking it up, for I think not 100% sure, that that is REALLY a split phase 12 volt transformer, IE CT to chassis ground and 2 6.3 heater suply at 5a ( x and y ),, it would be REALLY bad if this were true

like seen here https://i.imgur.com/QwNcmU0.png

The label shows a 6 volt secondary with a CT, which means to use the green leads and insulate the striped one, as stated before.

Got it hooked up and its working great. Thanks everyone! To confirm in case someone finds this doing a search the center wire was not used.