Dave Plowman (News) wrote in message
...
In article ,
Jeff Liebermann wrote:
What is the most likely failure mode of similar radios - dry joints?

If the radio only plays oldies and 1950's rock-n-roll, you have a
problem.

Oh I dunno. Better than a lot of modern stuff.

Dry joints? I've never had to lubricate my solder connections.

It's what describes a failed solder joint as well as anything - they can
look sort of dried out.

In order of frequency:
- Leaky batteries and corrosion damage.

That can kill a new one too.

- Grease on moving parts (tuning capacitor, volume pot, on-off switch)
has dried out.

Can't see dried out grease on a tuning capacitor stopping it working.

- Bad electrolytic caps

- Loudspeaker coil rubbing on magnet. Warped cone.

Same with that.

- Carbon comp resistors changing value.

- Difficulty finding schematics and docs.

They're usually so simple and basic you can wing it. And older stuff
didn't tend to have maker's special part numbers on components.

- Package leakage on the old round cylindrical xsistor packages.

Not seen that one. Aren't they glass encapsulated?

- Tiny xformer wires corrode.

- Crumbling plastic parts, rotting fake leather, peeling chrome
plating, peeling labels, and faded decals.

Again, most of these are cosmetic. Will still work, though.

- Rubber embitterment, especially the power cord.

PVC insulation was pretty common 50 years ago on hook up wire.

--
*The closest I ever got to a 4.0 in school was my blood alcohol content*

Dave Plowman London SW
To e-mail, change noise into sound.


Tin whiskers/ metalisation (Ag/Al ?) creep on the dies of transistors,
certainly on Ge quite common but I suppose we must expect to see more of it
on old Si transistors as well, having had decades now to develop.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/