Hand-soldered, 9-transistor Sanyo radio still works perfectly after 50
years!

What is the most likely failure mode of similar radios - dry joints?

"Graz" wrote in message
...


Hand-soldered, 9-transistor Sanyo radio still works perfectly
after 50 years!

That's life.

I have Sony pocket radios that are 45 years old that work properly. It's not
_that_ unusual.


What is the most likely failure mode of similar radios
-- dry joints?

Probably bad caps.

On Mon, 08 Sep 2008 11:20:31 GMT, (Graz) wrote:

Hand-soldered, 9-transistor Sanyo radio still works perfectly after 50
years!

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.

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

In order of frequency:
- Leaky batteries and corrosion damage.
- Grease on moving parts (tuning capacitor, volume pot, on-off switch)
has dried out.
- Bad electrolytic caps
- Loudspeaker coil rubbing on magnet. Warped cone.
- Carbon comp resistors changing value.
- Difficulty finding schematics and docs.
- Package leakage on the old round cylindrical xsistor packages.
- Tiny xformer wires corrode.
- Crumbling plastic parts, rotting fake leather, peeling chrome
plating, peeling labels, and faded decals.
- Rubber embitterment, especially the power cord.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

In article ,
William Sommerwerck wrote:
"Graz" wrote in message
...


Hand-soldered, 9-transistor Sanyo radio still works perfectly
after 50 years!

That's life.

I have Sony pocket radios that are 45 years old that work properly. It's
not _that_ unusual.

I have a 'Good Companion' 6 transistor radio built from a kit supplied by
Home Radio of Mitcham (south London) which still works fine. Bought in '62
with my first weeks pay...

It uses a PP9 battery which gives several months of heavy use - compare
that to modern designs. ;-)

--
*Is there another word for synonym?

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

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.

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/

"Dave Plowman (News)" wrote:

Jeff Liebermann wrote:

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.


That is called a 'cold solder joint' in the US, because it is
typically caused by too low of a soldering temperature to make a good
joint.


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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

In article ,
Michael A. Terrell wrote:

"Dave Plowman (News)" wrote:

Jeff Liebermann wrote:

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.

That is called a 'cold solder joint' in the US, because it is
typically caused by too low of a soldering temperature to make a good
joint.

Don't you talk about 'wetting' when solder flows? Turns from a solid to a
liquid? But whatever - either description works for me.

FWIW I'm not sure all failed joints are caused by too low a temp - you see
them on factory soldered boards too. Famously like round a LOPT - where
the vibration and heat causes the problem.

--
*Seen it all, done it all, can't remember most of it*

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

On Sep 8, 8:06*am, "William Sommerwerck"
wrote:
"Graz" wrote in message

...

Hand-soldered, 9-transistor Sanyo radio still works perfectly
after 50 years!

That's life.

I have Sony pocket radios that are 45 years old that work properly. It's not
_that_ unusual.

What is the most likely failure mode of similar radios
-- dry joints?

Probably bad caps.

yeah. but caps in transistor radios of that age lived an easy life
compared to those in tube radios, so maybe could survive longer.

i bet the solder joints in that thing were absolute perfection.

random old fart digression: for a while in college i worked at the
sony warranty repair place. we had an old sony table radio which had
survived a fire; melted into a random mass with a couple of knobs
pointed in random directions; of course, still worked fine.

"Dave Plowman (News)" wrote:

In article ,
Michael A. Terrell wrote:

"Dave Plowman (News)" wrote:

Jeff Liebermann wrote:

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.

That is called a 'cold solder joint' in the US, because it is
typically caused by too low of a soldering temperature to make a good
joint.

Don't you talk about 'wetting' when solder flows? Turns from a solid to a
liquid? But whatever - either description works for me.


Wetting is when the liquid solder flows completely over the oxide
free surface. It is one step of the soldering process, and the hardest
to control in automated soldering. A profile has to be created, and
carefully followed for constant quality. Air temperature, humidity and
barometric pressure changes can cause problems, as well as moisture that
has ben adsorbed into the blank PC board and components. Any of these
can cause cool spots, and in extreme cases cause the PC board to
delaminate as the moisture is boiled away.


FWIW I'm not sure all failed joints are caused by too low a temp - you see
them on factory soldered boards too. Famously like round a LOPT - where
the vibration and heat causes the problem.


Solder passes from a liquid to a solid state, not a dry state. Some
alloys also pass through a plastic state that allows movement as it
cools into the solid state. Any movement during the plastic state is
what gives the dull gray, rough surface of a cold solder joint. Use of
eutectic solder, which has a very narrow temperature range with a
plastic state, it reduces cold solder joints. 63/37 was the preferred
alloy, before the EU screwed the pooch with their ROHS bull****.

As far as bad solder on heavy pins, it takes more to bring them to
the proper soldering temperature, and causes more problems. You can
wave solder everything else perfectly, and not get the pins on a
transformer anywhere near hot enough for proper wetting. Since it takes
longer to bring them to the proper temperature, the pins need to be as
clean and oxide free as possible.

I was involved in improving our reflow process when the company moved
to higher pin count surface mount ICs. We had a horrible initial
failure rate when we added the newer devices to our process. We went
through a half dozen allows and ball sizes in the paste solder, and
several different flux blends before we found what we needed. At least
we started with a brand new Heller oven.


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

On Mon, 08 Sep 2008 14:38:18 +0100, "Dave Plowman (News)"
wrote:

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.

I prefer 300 year old classical music. Too bad they didn't have
xsistor radios back then.

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.

I don't seem much of that with hand soldered equipment. I used to do
warranty service on radios and such that were hand soldered in Japan
in the 1960's. There were plenty of unsoldered connections and even
parts that just fell out when we opened the box, but once they hit is
with a soldering iron, it stayed put. However, that's with a limited
number of manufacturers (about 4?) so others may not have been so
neat.

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

That can kill a new one too.

It's very common in older xsistor radios. The radio gets stored
somewhere with the batteries inside. The batteries leak. The rest
you can figure out. I collect HP calculators. Many of those I
purchase have severely corroded traces and contacts thanks to battery
corrossion.

- 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.

Never heard the scratchy noises while tuning a 365mmf tuning capacitor
on an old AM radio? The noise you hear are tiny sparks in the
bearings. Slightly conductive grease gets rid of that.

- Bad electrolytic caps

- Loudspeaker coil rubbing on magnet. Warped cone.

Same with that.

In the 1950's all speakers were paper cones. The coil to magnet
seperation was fairly small in order to produce a high efficiency
speaker. The cones are hygroscopic, warp when wet, and get easily
misaligned. I have several old radios in my collection that need to
be re-coned.

- 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.

True. There's often a tiny schematic taped to the inside of the
radio. Sometimes, the schematic actually matches the unit.

- Package leakage on the old round cylindrical xsistor packages.

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

Nope. I don't recall the exact failure mode. Purple pleague sorta
comes to mind on the early xsistors.
http://en.wikipedia.org/wiki/Gold-aluminium_intermetallics
Sealing problems around the leads allowed water incursion, which
rotted the wire bonds, was another.

- 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.

Ummm... you're actually going to listen to AM radio? All I ever hear
is talk radio. No music, unless you like the south of the border
variety. Anyway, I clean all my repairs, so that the repair job
*LOOKS* like it's been repaired. Customers like to see their machines
returned cleaned. Think of this as a restoration, not a fast fix.

- Rubber embitterment, especially the power cord.

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

Most of the rotted power cords I've had to deal with were RH, RHH, RHW
or similar rubber cords. They were primarily attacked by the Los
Angeles smog with a dash of UV embrittlement. However, many "plastic"
cords didn't do much better. They didn't crack or crumble, but got
very stiff. I recently recycled some cheater cords that are so stiff
that they broke when bent. Incidentally, some commercial two-way
mobile radios used rubber insulation well into the late 1950's.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

I own about three hundred very old radios.Some of them are transistor
radios, some of them are tube type radios.Some of them work ok.Some of
them sort of work.Some of them don't work at all.Some of them are over
fifty years old.
cuhulin

"N Cook" wrote in message
...
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.

Tin whiskers were not a problem on that vintage device.
In 1957 I was working at a semiconductor facility on Boston's Rte 128 that
was making transistors from scratch. And I do mean from scratch including
crystal growing on up to testing. We were producing devices essentially by
hand. Indium dots were diffused into germanium chips, finished assemblies
were mounted on headers and connections were made by a large contingent of
nimble fingered ladies.

Testing was straight forward for gain, H parameters etc. The challenge was
getting mixers that worked. The test bed was a radio chassis with a socket
in the mixer position. If the radio played, the transistor got shipped.

Charlie

Probably bad caps.

Yeah. But caps in transistor radios of that age lived
an easy life compared to those in tube radios, so
maybe could survive longer.

I don't know. I've had several KLH Model Eight table radios, all well over
40 years old, and none had electrolytic problems.

On Sep 8, 9:05*pm, "William Sommerwerck"
wrote:
Probably bad caps.
Yeah. But caps in transistor radios of that age lived
an easy life compared to those in tube radios, so
maybe could survive longer.

I don't know. I've had several KLH Model Eight table radios, all well over
40 years old, and none had electrolytic problems.

i dug an old macintosh 50w-2 tube amp (mono) out of a dumpster a
million years ago. it still worked, but almost all the caps were
crummy, electrolytic as well as oily paper, as well as several other
components. replaced them and it was a nice amp. when i sold it the
buyer was shocked that i would desecrate a classic amp like that. (i
had kept the removed components in a coffee can which went along with
the sale, so he was free to return it to its natural state). what made
it a mcintosh was the transformer(s?) which remained original, as they
were potted in about ten pounds of epoxy or something and made up 90%
of the mass and volume of the thing.

On Sep 8, 8:42*am, Jeff Liebermann wrote:
On Mon, 08 Sep 2008 11:20:31 GMT, (Graz) wrote:
Hand-soldered, 9-transistor Sanyo radio still works perfectly after 50
years! *

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.

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

around here the dry joints are the ones with strippers, the
authorities don't want those joints lubricated.

On Sep 8, 8:10*pm, wrote:
I own about three hundred very old radios.Some of them are transistor
radios, some of them are tube type radios.Some of them work ok.Some of
them sort of work.Some of them don't work at all.Some of them are over
fifty years old.
cuhulin

sounds like my friends.

Nah, I still use an old General Electric 8 transistor Am with 2 shortwave
bands radio that was made in Utica NY. It's got a far better tuner than you
typically get these days and still sounds quite good. Uses 4 c cells.