How to use Sams' Photofact. and vertical deflection problem.
 

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Are the voltage and resistance values "in-circuit" measurements? Should
the tv be off and unplugged? What if the actual voltage measurements
don't match those quoted in the photofact - Is the component bad?

Any good links on how to test tv components with a DMM?



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I had a problem with the vertical deflecion in my old Zenith.
Blackness started moving up the screen obscuring most of the picture.
It started off only covering a small portion of the screen, and
eventually moved up to where only the top 10% of the picture was
visible and the rest of the screen was black. Whacking the tv used to
help, but not for long.

This was my first tv, so I kept it. I finally have some ability to try
to fix it. I read a few tv repair books and www.repairfaq.org . I
cleaned up the inside from dust, and learned where each circuit module
was. I decided it was probably a fault in the vertical circuits.
There is even a burned resistor on that module. Though I thought it
might be a dried up electrolytic capacitor. Please keep in mind that
this is my first attempt at tv repair.

I finally plugged in the tv and turned it on. And the problem was not
there! Intermittent then. I tried heat and cooling (b/c I was afraid
to touch it). Then I used a plastic tube to press on the board, and
this fixed the problem! So I'm thinking it's a bad connection, because
pressing on the vertical module fixes it if it messes up.

Any comments? suggestions?



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I suspect the red output transistor on the CRT board. How can I check
this with a DMM and Photofact?



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Some other questions:

*My DMM is autoranging. Does this include a small range diode test?
(Fluke T5-1000)
*How can you determine which big capacitor is the main filter
capacitor?
*How do you actually test transistors - resistance, voltage,
in-circuit?

Thanks if anyone actually read this!
Tom K

Tom wrote:

Any comments? suggestions?

Yeah. This thing got a model number?

David, on the Illinois prairie.

The old 1978 Zenith is chassis - 23KC45. (vert deflection)

The newer Zenith is model - SY2551S (missing red)

My main problem is in testing though. Most of the techniques I've read
about are for out of circuit tests I think. I have the Photofact for
the sets, and I've tried taking voltage measurements and comparing
them, but I'm still unsure hw to go about things.