On Wed, 06 Jun 2007 18:28:48 -0500, Peabody
put finger to keyboard and composed:

It's a JVC AV-27920 television, circa 1995 or so.

I understand that manufacturers deliberately build in overscan so
that any shrinkage resulting from CRT aging won't produce visible
black borders. But I would like see all the picture.

The service menu has adjustments for vertical size and position, so
I assume I can use those to get rid of all, or at least most, of the
vertical overscan.

But there is no width or horizontal size adjustment, only horizontal
position.

So I would like to think about making changes to the circuit that
would give me this adjustment.

In theory, I guess I don't want to change the horizontal frequency,
just the relationship between the yoke and the guns on each line.
So maybe instead of an actual width adjustment, it would work well
enough to change where the scan begins, or ends, and then use the
position adjustment to center it again.

And I wonder if I could do this by adding additional inductance in
series with the horizontal deflection yoke, with the idea that more
inductance would slow down the rate of change in the yoke, so that
the beams don't progress horizontally as fast as before, and
therefore finish the line before reaching the edge of the screen.

Is this all crazy? It doesn't seem like it should be. I mean,
width/size adjustments are not unknown in the modern world, so it
should be possible to insert one. I just don't know enough about
televisions to know how to do it.

I would appreciate any suggestions anyone might have.

Oh, and I do have the schematic. Sams 4080.

Assuming your TV is faulty, I would check the tuning capacitor
attached to the collector of the horizontal output transistor.

- Franc Zabkar
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