I decided it would be a good idea to pull down my collection of radios, dust them off, test, and pack in big zip-lock bags with a couple of desiccant packets. Maybe I should have left well enough alone as about half of them have developed "issues" while being on the shelf for a few years.
Today's "victim" was a Royce 1-630 AM/SSB mobile radio. When I first turned it on it seemed to work OK, had 100+% modulation but a bit low on power, no biggie. But, after being turned on for a while it started to sound and act like an old tube rig with silver mica disease! The S-meter would constantly jump in time with what sounded like static crashes but I can hear and copy signals. I doubt this thing has any cans with silver mica wafer caps built in so I poked around some more.
I found VR11 (200 ohm BIAS trim-pot) in pieces and several other of the "economy" trim-puts very iffy looking. I then remembered when I got it VR1 (20 kohm AM S-meter) was fubar so I had replaced it with one of those little square blue trim-pots. I went ahead and replaced VR11 with a like part. I started looking at some of the others and I really don't feel good about them but in some spots there won't be room for one of the square pots.
Does anybody know if this is a common issue or are is it just my usual "lucky" project karma? Also, it would be nice to replace these with like parts but I have no idea what to call this type of trimmer or if they are still available - I've found some similar at Mouser but not exact and none of the part numbers in Sams are good anymore. Would be a shame to have to put this in the parts bin for a couple bucks worth of pots. Once I have them sorted then I can get back to the original problem.
73,
Today's "victim" was a Royce 1-630 AM/SSB mobile radio. When I first turned it on it seemed to work OK, had 100+% modulation but a bit low on power, no biggie. But, after being turned on for a while it started to sound and act like an old tube rig with silver mica disease! The S-meter would constantly jump in time with what sounded like static crashes but I can hear and copy signals. I doubt this thing has any cans with silver mica wafer caps built in so I poked around some more.
I found VR11 (200 ohm BIAS trim-pot) in pieces and several other of the "economy" trim-puts very iffy looking. I then remembered when I got it VR1 (20 kohm AM S-meter) was fubar so I had replaced it with one of those little square blue trim-pots. I went ahead and replaced VR11 with a like part. I started looking at some of the others and I really don't feel good about them but in some spots there won't be room for one of the square pots.
Does anybody know if this is a common issue or are is it just my usual "lucky" project karma? Also, it would be nice to replace these with like parts but I have no idea what to call this type of trimmer or if they are still available - I've found some similar at Mouser but not exact and none of the part numbers in Sams are good anymore. Would be a shame to have to put this in the parts bin for a couple bucks worth of pots. Once I have them sorted then I can get back to the original problem.
73,
