I just bought a 46-431 with a very nice wood case. The chassis is dirty but seems complete and the components seem original. It has all the tubes. I have not checked them, but have NOS tubes to replace all of them if I have to.
I have not checked the power transformer yet - am hoping that is OK.
Anywhere that I should look for trouble?
Thanks for any help in advance.
Pat Bunn
Don't plug it in until the DC power supply filter has been recapped and at least the paper wax capacitors in the audio section have been replaced. Test all coils and transformers with an ohmmeter so you can take early action to replace or repair. Use a "dim bulb" tester to apply initial power to the power transformer with all tubes out. Check AC voltages on the transformer. If all is fine then plug in the rectifier and test the B+. You're looking for smoke while testing. If B+ is where it should be then plug in some tubes and the speaker should be awake.
Service information is in the Library under the Service Info tab.
That's just an outline to get started. We're all here to answer questions. BTW your radio probably has rubber coated wire throughout. Be aware of this and make a plan to remedy this.
Thanks
I generally rebuild the entire power supply on a radio in this shape replacing all the resistors and caps. I definately won't plug it in until things are rebuilt and checked out.
I suspect this radio will need lots of replacement capacitors from the looks of the ones in it.
This radio has a combo dual .01uF capacitor/terminal strip for the incoming AC line. I'll probably remove it and replace the capacitors on a terminal strip, unless I am told this is a bad idea or someone has a better idea.
If the power supply dual electrolytic cap is easily removed, I'll probably gut it and stuff it with new caps. Replacement caps will be much smaller. I may increase the value of these if the rectifier tube can stand the increase. I haven't looked at the tube data yet.
Pat
The line filter caps in the bakelite block can be replaced with safety caps either stuffed in the block or on a terminal strip. It's not difficult to stuff them in the block. Instructions are in the Library. I usually rewire the power switch on the other side of the filter caps so they only have power when the radio is on.
Usually the input ps filter cap is 40 mfd or less but with a choke in there you can use 12 or 16.
Hello Pat,
I cleaned out the backlite block and put the safety capacitors inside of it !.
Sincerely richard
Started working on the radio. Someone has replaced the speaker in the past and butchered the power supply. Don't think they ever got it to work correctly.
I don't see where they replaced the field coil with a resistor. I have ordered a small 75mA choke and a new speaker. I think it will fit where the electrolytic cap was mounted on the back side of the cabinet.
Ripping out all the wax paper caps leaves lots of extra room. Pondering on whether to install a fuse in the rear chassis side? Probably will.
Installed a new line cord and have wired the AC line filter and the 6X5G tube. Hope to remove the multi cap and re-stuff it today. I also am replacing the rubber insulated hookup wire as I go.
There is an unusual "thing" on the back of the chassis with a single blue wire going to it. No resistance to chassis. It has two connections but only the one blue wire. No resistance from pin to pin or either pin to chassis. Any idea what this is?
Thanks for the help
Pat
Pat, install a fuse. These old transformers need extra protection especially from overload heat conditions. There's no telling how much it has endured over 75 years.
A photo helps us with identifying "things" with blue wires (you're telling us that wire is blue and not faded to brown?).