Identifying zener diode

[Dan]

JVC TD-V1050 3 head cassette deck. While working on it for an unrelated
problem, a small screwdriver slipped out of may hand & snapped a zener diode
in half! The diode in question is glass, about 1/10 inch long & is marked
only "C24". Am I correct in assuming this is a 2.4V diode? I couldn't
believe it when this happened, for one thing I'm not usually that ham-handed
and secondly this component is probably the only one on the board capable of
being broken this way.

Sorry for the rudimentary nature of the question ;-/

Dan

 

[BOB URZ]

JVC TD-V1050 3 head cassette deck. While working on it for an unrelated
problem, a small screwdriver slipped out of may hand & snapped a zener diode
in half! The diode in question is glass, about 1/10 inch long & is marked
only "C24". Am I correct in assuming this is a 2.4V diode? I couldn't
believe it when this happened, for one thing I'm not usually that ham-handed
and secondly this component is probably the only one on the board capable of
being broken this way.

Sorry for the rudimentary nature of the question ;-/

Dan

How do you know it a zener? I assume it has silk screen on the PC board
and that's how you know. If you know its a Power supply part, you need to
look for clues. Look at the Electrolytic caps connected to the same lines
as the zener. That will give you a clue. I would be more inclinded to think
24 volts. The voltage values of the caps will be helpful. If it was a 24 zener,
the caps would probably be 35 volt or so. If it was truly 2.4 volts, i would
expect 6 to 10 volt caps.

It might also be helpful to know the open circuit voltage with the zener out
of the circuit (careful doing this)

Bob

 

[Dan]

Bob-Thanks for the reply. Caps & volts are pretty inconclusive (for me,
anyway) ~0.7 volts open circuit, a connecting cap is 25V, others nearby are
50V. It is a zener as per the silkscreen symbol & is in the "vicinity" of
the power supply, but removed enough that it might serve another purpose?

Dan

 

[techforce]

Thats Why you will see a lot of people here recommend you take it to a
qualified Service Center.
If you dont know or feel confident in what you are doing, you could wind up
spending more money and time on it than would have been done if it were
given to a qualified Service Center.

If you dont mind being at the Mercy of those who have the Time to help you
in every problem of the Repair Here - then I guess its ok. But theres only
so much anyone can do given they are not present to see the Actual item.
There are no Guarantees in FREE help.

 

[BOB URZ]

Bob-Thanks for the reply. Caps & volts are pretty inconclusive (for me,
anyway) ~0.7 volts open circuit, a connecting cap is 25V, others nearby are
50V. It is a zener as per the silkscreen symbol & is in the "vicinity" of
the power supply, but removed enough that it might serve another purpose?

Dan

As was pointed out, sometimes when your in over your head take it to
a pro. But obviously you have some knowledge to know what a zener symbol
is.

Thinking further, the zener could be in a simple regulator, or be part
of a series pass transistor regulator with the zener controlling the base of
the transistor. If this is the case, you need to find the transistor and measure

the voltage on the collector and emitter. Then check the cap values around
the collector or emitter. If its a regulator, it should also be larger than
surrounding transistors or possibly be on a small heastsink. Also, look for
any low value resistors around this area and confirm there value with
a DVM.

Better you have some fun with it and try to fix it than it ending up in
the landfill.

Maybe someone here has the service manual and can look it up for you.
SOmetimes you get lucky, sometimes you don't

Bob

 

[Dan]

The bottom line is I have not used this machine in a couple years & was
planning to attempt selling it when I discovered it was no longer
operational. Given that dirt cheap cd-r recording has pretty much pulled
the rug out from under the utility of recording music on cassettes, the
machine is almost certainly not worth paying to repair, regardless of its
initial high quality. It may not sound much like it from these particular
posts, but I actually have a fair amateur background in electronics,
including training in a vocational high school program & technical college
years ago. Emphasis on the phrase "years ago" (late '70's). I also have a
fair bit of equipment, including 2 oscilloscopes. I have successfully
repaired many, many items over the years & have built quite a few more from
the schematic up. I don't do this because I'm cheap, nor to take bread out
of the mouths of anyone doing such work for a living, but rather because I
enjoy it. Consider me in the spirit of the "tinkerer" whose demise was
lamented in the recent Electronics/Radio Shack/Future thread. I found that
thread quite nostalgic, I did all that stuff, built Heathkits, etched my own
pc boards, ripped apart TV's etc for parts which I then carefully sorted &
stored away for future projects, subscribed to Pop Tronics, on & on. But
I'm afraid I'm a bit rusty. If this were my 3 year old plasma TV (which I
don't actually own, but just for purposes of illustration) of course I would
pay to have it repaired. I'm not looking for any guarantees, just some
suggestions. Failing that, I'll probably order a repair manual from the
site Alan was kind enough to point out.

And if previous experience is any indication, I will get the damned thing
running again ;-)

Dan

 

[Don Cleveland]

Go to the NTE site and do a search on C24.

http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm

Don Cleveland

 

[George]

Go to the NTE site and do a search on C24.

http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm

Don Cleveland

Hi Dan
In the power supply the have pico fuses they look like a transistor
with only two legs just check the resistance until you
find one that is open. You will have 3 or 4 in the power supply area on the
board.

 

[Dan]

Thanks Don, it only turns up a range of zeners, not the exact voltage, but
it's a resource I was unaware of & will no doubt use in the future on other
components.

Dan