panasonic travel tv 1 inch screen

[timmy]

does anyone have any ideas about lets say any transistor b@w tvs that the set has horizontal but it dont fill the screen and it dont have a width adjustment. any ideas what part of the circuit would be at fault.

[MickM]

Hi Timmy;
The Horizontal oscillator drives the horizontal output, which drives the yoke.
The horizontal output also drives the flyback for high voltage.

As sets age component values drift and change.
Resistors increase in value, electrolytics dry up and leak, and also decrease in value, or turn into resistors.

The output stage is a high stress circuit.
The horizontal oscillator is a tuned circuit about 15Khz.
If the oscillator frequency has drifted then the tuned circuit will not be at peak.
This will result in a narrow sweep, as well as low HV.

I would check all R's and C's for correct value and ESR.
Also the yoke could have a shorted turn, or a shorted/leaky cap across it.

To work in this area you need test equipment.
A Scope, DVM, Cap meter, ESR meter, ring tester, HV probe.
You can also lift one lead and tack a replacement part in place to test.

A yahoo search for "tv horizontal circuit":

http://search.yahoo.com/r/_ylt=A0oG7...c/horiz-tv.pdf

Which set are you working on?
Do you have the manual/schematic?

Mick M