Re: Deflection amplifiers...

Clay,
        I've been doing some thinking about converting a raster monitor to a
vector monitor. My baseline was a G-07. Save the tube, yoke, neck board,
HV section, and a few of the transistors on the main board. I believe one
could use the main board (with minor jumpering) as a HV supply and a RGB
gain stage. A new deflection board could be added to the side of the
chassy and wired into the main board power supply. (This is really just an
extension of John R's "raster hack" [see Re: Star Wars - fly back
suggestions?])

The yoke is another problem. The Horizontal windings have a few turns on
the Vertical. The good news is that this is a tap on the terminal block
and is therefore easily bypassed. The number of turns on the yoke is a
bigger problem. B=N*I, so the current goes down as the number of turns
goes up (good). The inductance of the yoke goes up as the square of the
number of turns (bad). Given that the required deflection voltage is Vdef
= L * dI /dt and factoring back in the number of turns (N) I get Vdef = L
* N^2 * dI/N /dt which reduces to Vdef = L * N * dI/dt. Which basically
sucks, because the number of turn on a raster yoke is probably 4 times that
of an XY. I could design a +/-120V deflection amp, but is really the right
answer?

So here are my questions:
1. Are XY yokes available in good quantities at reasonable prices?
2. If one were to design a HV section from scratch, is there a readily
available HV transformer, again, at a reasonable price?
3. Assuming one could modify a raster monitor, what one is the best to use?
(e.g. easiest to get, smallest dot pitch,etc)
4. What is most needed: complete XY monitors, Ampliphone HV replacement, or
WG HV replacement?

Thanks,

-Scott

At 04:02 PM 10/9/98 -0700, Clay Cowgill wrote:
>Awwww, crap...
>
>Remember the Apex Microtechnology Power Op-amps? (PA-07 and PA-09)
>
>They'd pretty much make for a two-component replacement deflection board
>for vector monitors. Well, here's the rub...
>
>Got my price sheet today. PA07 Qty 1-4 = $98.85! PA09 Qty 1-4 =
>$167.80! Yes, that's *each*.
>
>*grumble*
>
>Well, the PA45 might do the trick still-- and it's only $32 each in
>reasonable quantities...
>
>-Clay
>

--
Scott Swazey                QUALCOMM Incorporated Work: (619) 657-2419
mailto:sswazey@qualcomm.com V-209H                Pager:(619) 683-5210