For FB group Vintage Transistor Radios
Speaking of fuzzy garbled audio… I won another auction for a Zenith “Royal 510” which I’d never heard of. It turned out to be a Royal 250. The seller got no bids at all, so with less than a minute left I bid the minimum ten dollars.
I got it this afternoon. It needed the usual capacitors, but after I got done doing those, it was microphonic, any vibration from the speaker would set it off into a squawk or buzz. I started poking around to find a loose solder joint, and I finally found one and fixed it. But it still squawked. I had to poke around and flex the PC board quite a bit before I narrowed down the point that was causing the problem. It was a hairline crack in the PCB trace, least where one would expect, in the middle of a trace thickly covered with heavy coat of solder. I bridged the crack with two heavy wires imbedded in the thick solder. I don’t think it will break again. I guess the PC board was flexing when it was being shipped, and finally the trace cracked. The board itself looks okay.
I put it back together and Humpty Dumpty is working okay. In the center of this photo is a ‘dogbone’ shaped piece of solder with the almost invisible hairline crack in the middle.
