Motorola model A22N radio

[electra225]

I have this little AA5, plastic cabinet, PCB chassis, very basic. It's a pretty hot performer for what it is. In nice condition, would be perfect but for a missing gold "bright" from the tuning knob. I play all my little radios on a regular basis. It came this radio's turn recently, but it wouldn't play. If I tapped on the cabinet, it would play then quit again. I pulled the chassis and speaker and cleaned all the connections, tube sockets, reflowed the solder on the antenna connections and on the tuner. My diagnosis is SMD. Since it has a PCB chassis, it's not worth fixing. More trouble than it would be worth. I can still listen to it, I just need to tap the cabinet occasionally when it quits. IT seems to get better as it gets warmer.

[William]

Well, someday you might just say I need to fix this nice little radio just because.

Bill

[electra225]

I would have to usolder the IF cans from the PCB chassis. I don't believe the chassis would survive that. It has a minor case of SMD, but it won't get better. I guess the time will come where I have no choice. I could also hardwire the chassis if the heat from soldering caused damage to the traces.

[TC Chris]

Isn't SMD usually identified by lots of static-y crashing noises? Yours sounds like some sort of bad connection, maybe even an intermittent voice coil or OPT?

Chris Campbell

[electra225]

It has some of that as well. When I do the old wiggle trick, I get positive voltage on the grid of the IF amp.

[Dr. Radio]

Isn't SMD usually identified by lots of static-y crashing noises? Yours sounds like some sort of bad connection, maybe even an intermittent voice coil or OPT?

Chris Campbell

I know this is an older thread, but in regards to your question, read my response in this other thread about the "other form" of SMD....

viewtopic.php?p=17478#p17478

[TC Chris]

OK, I had forgotten that post. It prompts another question. Just last night I was emailing my brother about how copper oxide conducts poorly and silver oxide conducts very well. So I wonder if the oxidation issue has more to do with the metal contact tabs in the IF transformer?

Chris Campbell

[Dr. Radio]

Chris,

As far as GE in-house made IF transformers, I can tell you the "tabs" themselves are major contributors to the issue. I don't know what junk metal they used or what plating process but the ones I've done autopsy's on all have connection tabs that look dull gray at best.

The U.S. design of cheap IF cans with the electrical connection just "touching" of the connection was a horrible idea. But $$$ was on the mind of the manufacturers. Even when these radios were relatively new, guys were changing them out at the repair shops.