Hello Folks,

We have a Minolta X-300 film camera. Long story short this spring it
quit. The meter circuit was ok but no shutter and when pressing the
shutter the meter display would disappear.

Well, it was an electrolytic cap in the bottom of the camera, 220uF/4V
and really tiny. It actually leaked out. Took a while to find one that
would fit into the small cavity. Since some of you may experience the
same problem here is the part number:
United Chemicon APXC4R0ARA221MF60G (220uF/4V)

Mouser has these. I bent up the leads and slipped off the plastic SMT
carrier, then soldered it to the little flex. Be careful with those tiny
screws for the bottom lid (two different types). Don't lose them.

Now this old X300 contains a RoHS compliant capacitor :-)

Regards, Joerg

http://www.analogconsultants.com

Joerg wrote:

I've fixed numerous consumer electronics products
by just looking for the burped up electrolyte
from capacitors. Clean up the board, solder in
a new part and it works again. I was talking
to an old-school tv repair tech and he said that
it was about 60% of his repair work.

Hello Jim,

That is sad. 50+ years ago nearly all electrolytics were of decent
quality. Look around at our house: Tube radios from the 50's, a 60's
Hammond organ, all stuff where the caps have to stomach elevated
temperatures yet none has failed.

Today we buy a fancy product and the electrolytics fail. Sometimes the
leaked electrolyte takes circuit boards and other things along into the
abyss.

Regards, Joerg

http://www.analogconsultants.com

On Mon, 15 May 2006 20:06:32 GMT in comp.arch.embedded, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Just a couple interesting links:

http://catless.ncl.ac.uk/Risks/22.73.html#subj9
http://en.wikipedia.org/wiki/Capacitor_plague

Regards,
-=Dave

--
Change is inevitable, progress is not.

On Mon, 15 May 2006 20:06:32 GMT, the renowned Joerg
<notthisjoergsch@removethispacbell.net> wrote:

The cost difference between good and bad can be substantial, and even
the worst electrolytics usually outlast the warranty unless you're
pushing the voltage rating.

Try to find a capacitor for a 1/2 HP VFD mains filter that is rated to
last 8 or 10 years of typical 24/7 industrial operation and costs less
than the wholesale price of the finished product.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:cb5ag.76914$H71.59606@newssvr13.news.prodigy. com...
They probably lost a good deal of their capacity. Turn up the
volume, and watch the ripple increase on the HV supply.

Reliability has been traded for space. A while ago I got a
TEK465, all power supply caps had dried out. Only 10% of the
original capacity left. I found some new capacitors to replace
them, half the size of the originals...

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)

Hello Frank,

Not much though. Sometimes, sadly, tube gear has to be torn down because
parts aren't available anymore. The old Rhode&Schwarz SMF here in the
lab might await that fate. Whenever I do that I save the electrolytics,
measure them and keep the good ones. The usual, charge up across a
resistor and checking the slope. Lo and behold they usually still have
their capacitance at 30, 40, 50 years.

I am not familiar with those but the 7704A here in the lab is still
running just fine. From all the gear in the lab I had only two capacitor
failures. One dried out, the other happened during a transport in a
container. The guy on the crane let go and every box in it was reduced
in height by about 1/3. The cap broke off.

Regards, Joerg

http://www.analogconsultants.com

Hello Spehro,

Well, I'd expect caps to last a bit longer than just the warranty...

Regards, Joerg

http://www.analogconsultants.com

Hello Dave,


<electrolytic capacitors>

Yes, you really have to watch it. Especially when outsourcing purchasing
along with production. "But they told us these are equivalent and the
data sheet looked ok ...".

Regards, Joerg

http://www.analogconsultants.com

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:IA8ag.76984$H71.33846@newssvr13.news.prodigy. com...
Wahay!

The QC dept at one of my old employers had a "drop test" for new products -
in their freight packaging. IIRC, the first test was a drop onto concrete
from a "calibrated" height (i.e. from an arm out straight in while standing
on the truck loading bay in Goods Inwards). If nothing broke, great. The
second test was to drop (or, if necessary, launch, with or without
packaging) as far as it took for *something* to break... and then look at
what it was...

I never quite got used to the idea that there was a bunch of guys, working
for the same company, who were intent on breaking something I'd just spent N
months putting together.

We never let them play with a crane though.

Steve
http://www.fivetrees.com

Steve at fivetrees wrote:
We've done something similar. In the states,
UPS is the most common surface carrier. I
believe their accepted drop test is from 1.2
meters onto a hard surface. Once on each
face of the package and once on each corner.

Hello Steve,


One of the places where I worked did the same thing. But their gear had
to be really tough so it better be tested that way. They regularly had
to switch "thumping locations" because the concrete landing surface that
was regularly layered up was only allowed to be stomped so many feet
into the ground.

But this capacitor was in lab equipment. That's not meant to be treated
this rough. Although I did not quite understand why an electrolytic that
was 2" tall and heavy wasn't mechanically supported. It was on a
vertically mounted board. At least they could have laid it out so that
its terminals would have been above each other and not sideways. It was
a recipe for failure.

Regards, Joerg

http://www.analogconsultants.com

Joerg wrote:
Back when, big electrolytics came with a clamp. You firmly
attached the clamp to the chassis (or pc board later), inserted the
cap and held it firmly. Then you could add the wiring or soldering
or whatever. Routine.

--
"If you want to post a followup via groups.google.com, don't use
the broken "Reply" link at the bottom of the article. Click on
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"Reply" at the bottom of the article headers." - Keith Thompson
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Also see <http://www.safalra.com/special/googlegroupsreply/>

CBFalconer wrote:


Later they came with several extra pins just to provide a more solid
"foundation". Then I guess these were falling prey to cost reduction.

Regards, Joerg

http://www.analogconsultants.com

Joerg <notthisjoergsch@removethispacbell.net> wrote:

Well, if all equipment were only treated as it's meant to be, life
would be boring for at least some of us: from the ordinary repair guys
to those getting tasked with the ever-evasive "fool-proof" design.

Yes, but the mounting orientation had nothing do with that. That's
because Murphy's law, applied to transportation accidents, reads: "If
there is any direction your goods are ill-prepared to withstand
mechanical shock in, that is exactly the orientation the impact will
happen in."

In other words: toast _will_ land jelly-side down. Even if, knowing
this, you put the jelly on the bottom side or along one of the
edges. ;-)

Clever choice of orientation would help against long-time strain
during normal, as-meant-to-be-used operation. The only choice that
helps against random accidents to build the thing robust in *all*
directions. I.e. mechanically lock down everything that's big and
heavy enough or protrudes to the outside far enough to turn external
shock into internal stress on solder joints: all pieces jutting out of
the front panel, any and all magnetics, and all caps higher than
they're wide.

--
Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

Hello Hans-Bernhard,

True. I wish all engineers would think outside their box. For example by
hitching a ride on a freighter plane if they are allowed to, or at least
a on truck that goes from Shannon to Ballinsloe at full speed. After
that they'll design more carefully.

Yes. Like that lady that was convinced that earthquakes shake things
mostly in a vertical direction. Until she had half the pool water in the
living room.

That caps actually wasn't taller than wide. It was just heavy.

Regards, Joerg

http://www.analogconsultants.com