Restoring A WARDS AIRLINE RADIO MODEL 93BR-1201 WARDS AIRLINE RADIO MODEL 93BR-1201

[Rick73]

I am in the process of restoring this old radio. I believe that it was manufactured in the late 40's or early 50's. If anyone has some suggestions on where to start, I would appreciate that.

Thanks,
Richard

 

[BradtheRad]

Switching it on quickly sends a shock of high voltage through aged components. Tubes and capacitors are prone to fail at that time.

Do you have a variac? Use it to power up the radio slowly.

How slow is too slow? Certain circuitry can behave strangely if exposed to substandard voltage in the process. It would take an expert to predict if damage might result if you gradually raise voltage too slowly.

A different school of thought could say twenty seconds is reasonable for you to raise the voltage to normal. However long it takes the tubes to warm up.

 

[Rick73]

I don't have any idea of when it was last used. I is my sisters radio and I told her I could give it a shot. Here is a photo I got off of the internet of the chassis.

I suspect that the three electrolytics on the right side will have to be replaced. I have a copy of the schematic, but it does not show any values of the components. I was thinking of pulling the rectifier tube and just see if the transformer still works. The schematic is in a pdf and I'm not sure if one can post a pdf on this site.

I am a ham radio operator, but sadly I had to give it up. My license is still good, K0UXU, but as I can not hear, i sold all my ham gear years ago. It was a rather sad day when that gear went out the door.

 

[D.A.(Tony)Stewart]

Start with a schematic. https://www.radiomuseum.org/r/montgomery_93br1201a.html get a DMM to measure the DC hiV and the ripple AC.

An alternative to Brad's idea is to put a 60W lightbulb in series so the diode tube surge current is reduced charging up the caps which may need repair. If the light stays bright, there is a problem.