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How to eliminate horizonal overscan when no service adjustment?

F

Franc Zabkar

Jan 1, 1970
0
Franc Zabkar says...


I left out one cap (C526) back near the 134V source. So it
should look like this:

|---------------FLYBACK---------|
| |
| |
| |
134V--|--R526-|----L521------|--YOKE--|---Q522---|--GND
1.5K | | | H.OUT |
| | | |
| | | |
|--R530--C527--| |---C524---|
|
|
C526
|
|
GND


But somehow I don't think that's what you had in mind. The
"bottoms" of both the flyback primary and the horizontal
deflection coil are tied together as shown. They go to
ground through the low-impedance path to ground when Q522
turns on, and through C524. at other times.

The yoke current (0.5A - 1A?) flows through L521 and C526, not R526.
In fact I'm still uncomfortable about the circuit. AFAICS, a
traditional horizontal deflection circuit doesn't need R526. Can
someone tell me what this resistor does? I understand that R530 and
C527 are required to dampen the ringing in L521, and C526 blocks the
DC path through the yoke.

As for where to place the additional width coil, put it between L521
and C526.

- Franc Zabkar
 
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