I think I might have toasted a/some transistor/s last night. I
dropped a test probe into my tape deck, and saw sparks. I put it back
together to check everything and the transport motor was running
slow. In the power inverter there is a blueish looking 2N1542, and
some strange metallic crystal deposits on the inside of the case
around this transistor. The transistors in the inverter check good.
They both have a lower forward bias voltage .18V, but I am assuming
that this is due to the fact that it is either a power transistor or a
Germanium transistor. However, I have had transistors check good with
on the diode setting of my DVM and they actually turned out to be
bad. Any advice?

Thanks,
Chris KQ6UP

On Jan 29, 12:43*pm, Chris wrote:
I think I might have toasted a/some transistor/s last night. *I
dropped a test probe into my tape deck, and saw sparks. *I put it back
together to check everything and the transport motor was running
slow. *In the power inverter there is a blueish looking 2N1542, and
some strange metallic crystal deposits on the inside of the case
around this transistor. *The transistors in the inverter check good.
They both have a lower forward bias voltage .18V, but I am assuming
that this is due to the fact that it is either a power transistor or a
Germanium transistor. *However, I have had transistors check good with
on the diode setting of my DVM and they actually turned out to be
bad. *Any advice?

Thanks,
Chris KQ6UP

If there are crystal-like deposits, look for a bad electrolytic that
could have "popped" and caused them.

On Jan 29, 2:11*pm, "hr(bob) "
wrote:
On Jan 29, 12:43*pm, Chris wrote:

I think I might have toasted a/some transistor/s last night. *I
dropped a test probe into my tape deck, and saw sparks. *I put it back
together to check everything and the transport motor was running
slow. *In the power inverter there is a blueish looking 2N1542, and
some strange metallic crystal deposits on the inside of the case
around this transistor. *The transistors in the inverter check good.
They both have a lower forward bias voltage .18V, but I am assuming
that this is due to the fact that it is either a power transistor or a
Germanium transistor. *However, I have had transistors check good with
on the diode setting of my DVM and they actually turned out to be
bad. *Any advice?

Thanks,
Chris KQ6UP

If there are crystal-like deposits, look for a bad electrolytic that
could have "popped" and caused them.

There were no caps under the cover of the inverter. Really strange.
I purchased 2 new transistors (there are two in a push/pull
configuration). However, I am hesitant to install them as they were
$20/transistor. The discolored transistor tests good.

Thanks,
Chris

Chris wrote in message
...
I think I might have toasted a/some transistor/s last night. I
dropped a test probe into my tape deck, and saw sparks. I put it back
together to check everything and the transport motor was running
slow. In the power inverter there is a blueish looking 2N1542, and
some strange metallic crystal deposits on the inside of the case
around this transistor. The transistors in the inverter check good.
They both have a lower forward bias voltage .18V, but I am assuming
that this is due to the fact that it is either a power transistor or a
Germanium transistor. However, I have had transistors check good with
on the diode setting of my DVM and they actually turned out to be
bad. Any advice?

Thanks,
Chris KQ6UP


Are the "crystals" shattered glass from glass sealing/encapsulation, around
the leads of the transistor? Replace with any old Si device and run at low
voltage and see what happens around it before sacrificing a second Ge power
tr


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://diverse.4mg.com/index.htm

On Jan 30, 1:19*am, "N_Cook" wrote:
Chris wrote in message

...

I think I might have toasted a/some transistor/s last night. *I
dropped a test probe into my tape deck, and saw sparks. *I put it back
together to check everything and the transport motor was running
slow. *In the power inverter there is a blueish looking 2N1542, and
some strange metallic crystal deposits on the inside of the case
around this transistor. *The transistors in the inverter check good.
They both have a lower forward bias voltage .18V, but I am assuming
that this is due to the fact that it is either a power transistor or a
Germanium transistor. *However, I have had transistors check good with
on the diode setting of my DVM and they actually turned out to be
bad. *Any advice?

Thanks,
Chris KQ6UP

Are the "crystals" shattered glass from glass sealing/encapsulation, around
the leads of the transistor? Replace with any old Si device and run at low
voltage and see what happens around it before sacrificing a second Ge power
tr

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://diverse.4mg.com/index.htm

Well my dad and I took a closer look at the situation. I would say
for sure they are metallic crystals. However, the transistor that is
in there now has been blued from excessive heat, there is no rupture
on the can, so we figured there was a transistor that had blown in
there before and it had been replaced. It is pretty obvious that it
was the transistor that caused the deposits because of the patterns
and positions of the markings. If I were to take a stab I would say
that they are Ge crystals. The crystals are really small and they
look like this:

http://tinyurl.com/yzt74ou

Pretty strange eh?

Thanks,
Chris Maness

On Jan 30, 5:33*am, Meat Plow wrote:
On Sat, 30 Jan 2010 09:19:19 -0000, "N_Cook" wrote:



Chris wrote in message
...
I think I might have toasted a/some transistor/s last night. *I
dropped a test probe into my tape deck, and saw sparks. *I put it back
together to check everything and the transport motor was running
slow. *In the power inverter there is a blueish looking 2N1542, and
some strange metallic crystal deposits on the inside of the case
around this transistor. *The transistors in the inverter check good.
They both have a lower forward bias voltage .18V, but I am assuming
that this is due to the fact that it is either a power transistor or a
Germanium transistor. *However, I have had transistors check good with
on the diode setting of my DVM and they actually turned out to be
bad. *Any advice?

Thanks,
Chris KQ6UP

Are the "crystals" shattered glass from glass sealing/encapsulation, around
the leads of the transistor? Replace with any old Si device and run at low
voltage and see what happens around it before sacrificing a second Ge power
tr

Do we know what brand/model deck this is?

It is made by a movie sound company called Amega, and the model is
M-3. I have another post in this group that goes into more detail
about this unit. I have moved this thread to a yahoo group I would
like to encourage you to join so that you can see all of the posts:

http://movies.groups.yahoo.com/group/syncsound/

Regards,
Chris Maness