RCA 56×3 – First Steps… Inspection

OK, so I explained why I was doing this… let’s face it, the challenge is also interesting.

I started by pulling the chassis out of the radio, and wiping off 50 or so years of dust and grime. I knew the cord would need to be replaced, since someone had cut off or pulled off the plug… based on this I expected a rewire along the line.

The first things I noticed were a torn speaker cone and the fact that the dial cord was a mess, and needed to be re-strung. (it was just hanging off the front when I pulled the radio out). Just to try the mechanism out and make sure things were functional, I jury-rigged some wire where the normal spring should be… it worked, but would occasionally unspool and not hold tension. I figured out later that the dial face was bent on one side (visible in the photo below). Straightening this out put the edge pully back in line with the capacitor connected pulley.

Temporary Dial Cord Testing
Torn Speaker Cone

All in all, it was in decent mechanical shape, save for the antenna in the back being bent in half. At first, I thought thers was a bad connection on the antenna, but it seems like I have all 4 wires on the loops, so I just need to check out the connections to the chassis.

I first looked over the bottom of the chassis, looking for obvious damage, blown capacitors, burnt resistors, bad wiring…. the radio was essentially untouched, from what I could tell. This was both good and bad…. good in that it was all intact. Bad in that the 76 year old rubber coated wiring was very brittle.

Underside – As Bought

just to see what I was up against, I put the radio on a variac, and, over a period of about a half hour, brought it up to line voltage. Around 80% of line voltage, I was greeted with AC hum. Nothing I did past this brought any new noises, besides a few pops if something was tapped on the chassis.

At this point, I wasn’t sure if I had a bad tube, or some really bad caps. Off to Ebay to search for NOS tubes. I had already acquired a box of 600V and a box of 3 kV capacitors for another radio from Amazon – polyester caps are pretty readily available in multi-value assortments, shipped in a nice divided box, for about $20 each. I also had to find replacements for the main electrolytics on the power supply, since I didn’t really have a lot of faith in those, based on the hum.

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