Replacing a variable capacitor

[Marco De Vitis]

Hi, I've got a newbie question to ask.
In short: if I'm going to replace a small variable capacitor in a TV,
being it "variable", I'd expect I'll have to regulate it somehow...
won't I? And how?

Extended version: I recently asked for help here on repairing a Sony TV
(KV-X2531A, chassis AE-1C) which was losing color for short times; the
thread subject was "Intermittent color/bw on Sony TV".
A person who kindly answered by mail did the right guess: a variable
capacitor near the subcarrier oscillator. I swapped it with the
identical one which was under the other nearby oscillator, and the TV
now works fine!

Now, supposing I want to totally replace them and supposing I can find
them in a local electronic shop, being "variable" capactors I'd expect
some kind of regulation to be needed... but they are just small circular
red/orange thingies with a cross screwdriver "slot" on top, and I can't
see any values or anything on them... Will I really need to regulate
them? How can I do it?

Thanks a lot for any info.

 

[Rheilly Phoull]

You will have to find the value of course, but they are simply adjusted by a
non metal tool (screwdriver type tip) to suit the operation of the circuit.

 

[Sam Goldwasser]

Hi, I've got a newbie question to ask.
In short: if I'm going to replace a small variable capacitor in a TV,
being it "variable", I'd expect I'll have to regulate it somehow...
won't I? And how?

Extended version: I recently asked for help here on repairing a Sony TV
(KV-X2531A, chassis AE-1C) which was losing color for short times; the
thread subject was "Intermittent color/bw on Sony TV".
A person who kindly answered by mail did the right guess: a variable
capacitor near the subcarrier oscillator. I swapped it with the
identical one which was under the other nearby oscillator, and the TV
now works fine!

Now, supposing I want to totally replace them and supposing I can find
them in a local electronic shop, being "variable" capactors I'd expect
some kind of regulation to be needed... but they are just small circular
red/orange thingies with a cross screwdriver "slot" on top, and I can't
see any values or anything on them... Will I really need to regulate
them? How can I do it?

Did you try swapping it back? Maybe it was just a bad solder joint.

Variable capacitors rarely go bad.

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[Sofie]

AGREED..... almost NEVER go bad unless they have been broken by improper
adjustment or excessive force.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

snipperoo:

 

[Sam Goldwasser]

Il 23/07/2003, alle ore 17:49, Sam Goldwasser ha scritto:


Indeed, I suspect the repair man who came here before already tried
simply redoing the joints, judging on the signs I noticed on the board
and on the different look of that 4 joints. But it didn't work.

I will try swapping them back anyway, because it could save me some
work, but the person who answered me by mail clearly told that having
those capacitors fail is a common problem; I quote: "i have left the
trade recently so regrettably dont have any spares anymore but these are
very common failures prob the most failed items on sony tv".

So... I'm pretty confused by the contrasting opinions.

Well, go by his experience. I'm going by knowledge of how they are
constructed.

As far as replacement, if you can't get something exact, one thing to
do might be to take both of them to a repair shop and see if they can
either provide a replacement or measure the good one so a generic variable
cap could be ordered.

--- sam | Sci.Electronics.Repair FAQ Home Page: 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 Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the Feedback Form at repairfaq.org. Thanks.

 

[john]

Very rare indeed does one go bad...

"i have left the trade recently so regrettably dont have any spares anymore but these are
very common failures prob the most failed items on sony tv".

/\ /\ /\
/\
Complete Rubbish.


Kip