Techs: What's on your Shelf of Weird Things?

[Matt J. McCullar]

I imagine that any bench tech who's been fixing electronic stuff for a while
has at least a couple of components housed on what I call The Shelf of Weird
Things: items that caused a very bizarre problem, or look strange, or
whatever.

Here are a few things from mine:

* A three-legged resistor. It used to be two separate power resistors, but
one got so hot it exploded and fused itself into the identical resistor
immediately next to it on the circuit board. It looks like a letter "Y" and
even close inspection makes one suspect it was actually manufactured this
way.

* A 7805 voltage regulator that works as long as the input voltage is from 8
to 12 volts, but when it goes any higher than that, the output voltage drops
to about 3 volts.

* A 1-watt carbon resistor that's missing a 1-mm wide band of carbon,
exposing the internal element. Looks like it was lasered neatly out.
Resistor still tests good, though.

* A 1N4001 diode with the cathode marking on the wrong end.

* Transistors with the wrong part numbers printed on them! (Took us a
LOOOONG time to figure this one out!)


Others I've heard about:

* Multimeter test leads that accidentally carried too much current through
them, instantly fusing the internal wires into one big, solid mass. Some
tech was trying to measure the high voltage on a laser power supply but
forgot to switch the meter from "Ohms" to "Volts." Now he's got a fried
meter and red and black coathangers.

 

[b]

I imagine that any bench tech who's been fixing electronic stuff for a while
has at least a couple of components housed on what I call The Shelf of Weird
Things: items that caused a very bizarre problem, or look strange, or
whatever.

Here are a few things from mine:

* A three-legged resistor. It used to be two separate power resistors, but
one got so hot it exploded and fused itself into the identical resistor
immediately next to it on the circuit board. It looks like a letter "Y" and
even close inspection makes one suspect it was actually manufactured this
way.

* A 7805 voltage regulator that works as long as the input voltage is from 8
to 12 volts, but when it goes any higher than that, the output voltage drops
to about 3 volts.

* A 1-watt carbon resistor that's missing a 1-mm wide band of carbon,
exposing the internal element. Looks like it was lasered neatly out.
Resistor still tests good, though.

* A 1N4001 diode with the cathode marking on the wrong end.

* Transistors with the wrong part numbers printed on them! (Took us a
LOOOONG time to figure this one out!)

Others I've heard about:

* Multimeter test leads that accidentally carried too much current through
them, instantly fusing the internal wires into one big, solid mass. Some
tech was trying to measure the high voltage on a laser power supply but
forgot to switch the meter from "Ohms" to "Volts." Now he's got a fried
meter and red and black coathangers.

On a related note, i've got a collection of stuff retrieved from
inside vcrs.
toys, straws, audio c60s, coins , etc.

and evidence of botched 'repairs', like the line transformer with
charred arc holes in, someone had stuck chewing gum and sellotape over
in an attempt to 'fix'.

will think about what else i have and post back!

-B

 

[Meat Plow]

I imagine that any bench tech who's been fixing electronic stuff for a while
has at least a couple of components housed on what I call The Shelf of Weird
Things: items that caused a very bizarre problem, or look strange, or
whatever.

Here are a few things from mine:

<snipped for brevity>

I have some microwave stuff from Western Electric that not too many would
even know which end was which or even be able to take a decent guess as to
what it did. Hell I don't even know and I've had this crap for 20 years

 

[JANA]

More so than having weird technical problems, try evaluating some of the
customers! Some of them have the wildest stories about their TV or
themselves.

--

JANA
_____


I imagine that any bench tech who's been fixing electronic stuff for a while
has at least a couple of components housed on what I call The Shelf of Weird
Things: items that caused a very bizarre problem, or look strange, or
whatever.

Here are a few things from mine:

* A three-legged resistor. It used to be two separate power resistors, but
one got so hot it exploded and fused itself into the identical resistor
immediately next to it on the circuit board. It looks like a letter "Y" and
even close inspection makes one suspect it was actually manufactured this
way.

* A 7805 voltage regulator that works as long as the input voltage is from 8
to 12 volts, but when it goes any higher than that, the output voltage drops
to about 3 volts.

* A 1-watt carbon resistor that's missing a 1-mm wide band of carbon,
exposing the internal element. Looks like it was lasered neatly out.
Resistor still tests good, though.

* A 1N4001 diode with the cathode marking on the wrong end.

* Transistors with the wrong part numbers printed on them! (Took us a
LOOOONG time to figure this one out!)


Others I've heard about:

* Multimeter test leads that accidentally carried too much current through
them, instantly fusing the internal wires into one big, solid mass. Some
tech was trying to measure the high voltage on a laser power supply but
forgot to switch the meter from "Ohms" to "Volts." Now he's got a fried
meter and red and black coathangers.

 

[[email protected]]

More so than having weird technical problems, try evaluating some of the
customers! Some of them have the wildest stories about their TV or
themselves.

I'm glad I dont repair vacuums.
http://www.google.com/search?client=opera&rls=en&q=dustette+bmj+OR+medical&ie=utf-8&oe=utf-8


NT

 

[Bill Janssen]

<snipped for brevity>

I have some microwave stuff from Western Electric that not too many would
even know which end was which or even be able to take a decent guess as to
what it did. Hell I don't even know and I've had this crap for 20 years

Post some pictures. I bet someone on the list will know what you have.

Bill K7NOM

 

[Sam Goldwasser]

OK, here's one:

http://repairfaq.cis.upenn.edu/Misc/sale/thing-1.jpg

Inside, are two nested cylinders that are electrically insulated from
the others, but attached to two of the pointy probes on the left via
the two middle flanges.

What is it?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[Pinballer]

heating element?

OK, here's one:

http://repairfaq.cis.upenn.edu/Misc/sale/thing-1.jpg

Inside, are two nested cylinders that are electrically insulated from
the others, but attached to two of the pointy probes on the left via
the two middle flanges.

What is it?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above
is
ignored unless my full name AND either lasers or electronics is included
in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[Sam Goldwasser]

heating element?

Doubt it. Nothing between the cylinders except air.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[Meat Plow]

Doubt it. Nothing between the cylinders except air.

Laser gizmo?

 

[Bill Janssen]

Doubt it. Nothing between the cylinders except air.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

My guess (and it is a guess) is that it is a standard capacitor. Don't
understand why it would have the pointy probes though.

Bill K7NOM

 

[m kinsler]

http://repairfaq.cis.upenn.edu/Misc/sale/thing-1.jpg

Inside, are two nested cylinders that are electrically insulated from
the others, but attached to two of the pointy probes on the left via
the two middle flanges.

It looks like a shielded four-point probe for determining the sheet
resistance of some soft material. If so, the shoulders on two of the
probes would maintain a uniform penetration distance. I seem to
recall that in such applications, two of the probes are connected
across a voltage source in series with an ammeter and the other two
are connected across a voltmeter. Presumably there'd be a connection
to instrumentation cables.

The only problem with this theory is that the finish on the device
doesn't seem correct for this sort of a job.

M Kinsler

 

[m kinsler]

Going back in my memory, I think I've actually seen something like
this before, and now I think maybe that it's not a four-point probe,
but some sort of RF antenna element. Those probes look awfully
familiar somehow.

This is an excellent exercise.

M Kinsler

 

[Eeyore]

I imagine that any bench tech who's been fixing electronic stuff for a while
has at least a couple of components housed on what I call The Shelf of Weird
Things: items that caused a very bizarre problem, or look strange, or
whatever.

Here are a few things from mine:

I reckon my best is a KT88 with a molten anode.

Graham

 

[Ron(UK)]

OK, here's one:

http://repairfaq.cis.upenn.edu/Misc/sale/thing-1.jpg

Inside, are two nested cylinders that are electrically insulated from
the others, but attached to two of the pointy probes on the left via
the two middle flanges.

What is it?

Flux Capacitor?

Ron(UK)

 

[Sam Goldwasser]

Going back in my memory, I think I've actually seen something like
this before, and now I think maybe that it's not a four-point probe,
but some sort of RF antenna element. Those probes look awfully
familiar somehow.

Hopefully, it'll come to you while your sleeping. But I really
do have no idea. I got it in a box of junk.

http://repairfaq.cis.upenn.edu/Misc/sale/thing-1.jpg
http://repairfaq.cis.upenn.edu/Misc/sale/thing-2.jpg

Again, there's nothing inside besides two smaller nested cylinders,
electrically insulated from the outer one with glass beads between
the flanges.

I rather like the idea of the probe, except there are only 3 electrically
separate contacts and then how does one connect to it?

This is an excellent exercise.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[jakdedert]

I reckon my best is a KT88 with a molten anode.

Graham

I still hang on to the pair of slip-joint pliers with which I tried to
loosen a mains lug in a 100 amp disconnect box...live. If I open the
pliers fully, one side of the jaw is a perfect fit for a certain size
allen screw.

One night at a gig, the house electrician left unexpectedly, holding
150' feet of our '0' feeder cable captive. I had no way to shut off the
power and the truck was fully loaded. I bade everyone give me plenty of
room, put one hand in my pocket and attacked the problem with my handy
slip-joints. I had all three hot legs disco'd and was going after the
neutral when the slip-joints...slipped.

I was ready, though and jumped back as soon as I felt them let go. It
made a pretty spectacular ZZZAP! and blew the tool clean out of the box.
They have a pretty nasty gash melted into the side that I use to
remind me not to be stupid.

I solved the problem by cutting the feeder where it came out of the box
and left eight or ten inches behind.

jak

 

[m kinsler]

I still hang on to the pair of slip-joint pliers with which I tried to

loosen a mains lug in a 100 amp disconnect box...live. If I open the
pliers fully, one side of the jaw is a perfect fit for a certain size
allen screw.

The diagonal cutters on my pliers have a nice notch that I
inadvertently fabricated when I cut through an energized line cord one
fine day. It makes a nice wire-stripping notch.

M Kinsler

 

[James Sweet]

The diagonal cutters on my pliers have a nice notch that I
inadvertently fabricated when I cut through an energized line cord one
fine day. It makes a nice wire-stripping notch.

M Kinsler

Been there, done that. Shut off the circuit breaker, then cut the wire and
POW! Oops, that wire snaked off to a different circuit! Breaker was now off
though

 

[Bob Weiss]

I have a TIP-41 transistor that works perfectly until the package
exceeds ~90 degrees F. Then the B-E junction goes open. Let it cool, and
it works again. You can watch the junction open and close with the heat
from your fingers. I assume a defective wirebond to the die is to blame.

I also have a 6550 tube that lost negative grid bias while operating.
The tube got so hot that the glass envelope melted and "sucked in" to
touch the plate.

Bob Weiss N2IXK