Hello everyone. I built a new battery pack for this AC/DC radio/phono. There is a 4 pin plug that used to fit into an Everready battery pack that had A/B of 90 and 1.5 volts. My question is, from the schematic showing the plug and the 4 pins,2 for the 90 and 2 for the 1.5(filaments). It does not show which go to which bettery. There are a yellow, blue, brown and black wire on the 4-pin plug. If I just randomly connect these by trial and error, I am afraid I will blow the filaments out with 90 volts. Is there a way to determine which go to which?

Use your ohmmeter, and just trace out those four wires, that should solve it.

:Use your ohmmeter, and just trace out those four wires, that should solve it.
:
Hi Brian,

I am a novice, how do I actually do that with my meter. Wire to wire until i get 1.5 VDC connected with the 1.5 volt battery pack?

A starting point is the battery connector cable coming out of the radio. These usually have four pins
- two closly spaced, two widely-spaced. The wide-spaced pins are for the 90V B+ and the narrow-spaced pins are for the low-voltage tube heaters.

If you hold the battery connector with the pins facing you, the two narrow-spaced pins at the top, the + terminals for both supplies will be the two pins on the right.

Consider this just a starting point, not gospel- I am not an expert on all battery packs that ever existed, and yours may be an oddball. But armed with the info above, it should be a simple matter for you to confirm the radio battery connector pinouts against the schematic.

Doing a little more research, the blue wire was the RMA color standard for the B+ battery connection, with the yellow wire being for B-. If these two wires happen to be on the two wide-spaced pins of your radio's battery plug, you are halfway home.

RMA standard for the A- (heater) line was black, but the standard for A+ was red. In all probability the brown wire in your set is the A+ line.

Once you think you have identified the two battery lines that go to the tube heaters, you can temporarily connect up a flashlight battery to the two pins and turn on the set. If the tubes light up, you have guessed right. If you guessed wrong, no harm will have done to the set since the B+ isn't hooked up.