On Mon, 11 Jun 2007 17:39:21 -0500, Peabody
put finger to keyboard and composed:

Franc Zabkar says...

Below is the circuit for the horizontal deflection. (You
would have to view it using a non-proportional font.)

When Q522 turns on, it grounds everything - the yoke circuit
and the flyback primary in parallel, both fed by the 134V
supply.

Does it matter where I insert the coil? I had thought maybe
immediately before or after R526, but I'm not sure if it
matters which one.

I assume the value of L521 should not be messed with.

Placing it immediately before or after the yoke would
require cutting one of the wires going to the yoke, which I
would rather not do.


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



That doesn't look right. The LH end of the yoke normally
goes to ground via another capacitor (not the tuning
cap, C524).

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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