Re: Noticed new vector monitor discussions, this is my input...

Wouldn't it just be simpler to intercept the signal to the deflection
amps and insert the vector signal there?

A daughter-board for an exisiting monitor could then be made that has
the proper connector for the vector game, and place simple protection
and spot killer circuitry on it.

This way an exising monitor could be used, with simple trace cutting and
soldering of wires from a daughter board to the existing monitor board,
and installation into the game.

Thoughts? It would probably be much cheaper than replacing the yoke,
assuming of course that the existing yoke could handle that form of
deflection.

    - Matt

James Nelson wrote:

> Thanks for your input. Here are some comments on it: >...winding your
> own yoke may well be almost impossible... I agree and I plan to have
> them done by a standard yoke winding company. >...electronic pin
> correction... Thanks for mentioning it. If pincushion is a problem, I
> can inject some of the y signal into the x drive. I'll probably put a
> trimpot in for this adjustment. I noticed that some of the 19" units
> seem to do this with one or two turns on a separate winding too. I
> need to take the time to understand what Clay's display corrector is
> all about too. http://www.multigame.com/display.html >...double the
> drive-use 2 driver boards, and 2 sets of outputs... The topology and
> devices are all wrong for that use, especially the way you described
> using them on each side of the winding. They use the ground side for
> feedback, and feedback is what will get you in trouble every time with
> this. The closest thing you could do that would to beef up the drive
> wouldn't require a second control board at all: Just get an extra set
> of identical transistors, put it them parallel, with the first set,
> and connect the outputs of each through a resistor like 1 ohm, 3
> watt. >How about boosting the voltage to the board?>The driver bias
> could be adjusted to compensate,>and getting hi-power transistors at 6
> Amps and>200 Volts are possible now. I don't quite understand what the
> voltage increase is supposed to accomplish. You can try this right
> away by bypassing the voltage regulator transistors on your power
> supply. In fact, there is an evil tech document,
> http://www.gamearchive.com/video/manufacturer/atari/vector/monitors/wg_color/final_solution.txt,
> that someone actually reccomended this. (What were they thinking?) The
> power dumped across a transistor (or any device) is going to be
> precisely equal to the voltage across it times the current through
> it. The current, in a correctly working drive, at any given moment
> will be the same no matter what the voltage input is becuase the
> current is what is fed back. The conclusion to draw here is that you
> want the voltage to be as low as you can make it so that you are just
> above the threshold of degrading performance. Increasing the voltage
> would be desirable only if you couldn't get enought deflection or your
> draw speed was being limited (warped vector draws). In your case,
> where you are going to make a custom vector game from scratch, maybe
> higher voltage would be good, but I wouldn't do it ever unless the
> monitor couldn't keep up with the game. By the way, I think those
> existing transistors are 10 amp 100V devices. Good enough on
> paper. Have a nice day,James====================================
>
> ----- Original Message -----
> From: Aaron Howald
> To: vectorlist@lists.cc.utexas.edu
> Sent: Friday, October 22, 1999 2:49 AM
> Subject: Noticed new vector monitor discussions, this is my
> input...
> Hi to all of you! Since I work on TV's for a living, I
> thought I'd add my input to the fray... Firstly,I think
> winding your own yoke may well be almost impossible. Unlike
> a standard coil (like a relay) the windings are staggered,
> crossed over on each other in a wild fashion, and precisly
> placed. All of this is for convergence assist+pin correction
> on some yokes. Doing this by hand is a grisly task, at
> best!Second, some obsevations on standard tv yokes. 13" tv's
> NEVER have any electronic pin correction at all. I assume
> this is because of the small screen size... 19" sets
> generally do not either, but most 25" do, and 27"-up ALWAYS
> have the correction. I assume with larger max deflection
> angles+longer beam travel, it becomes a nessessity. There
> is 1 25" set I know of that has no correction, and looks
> fine-other sets use a complex board to do it...but I
> wonder, if the yoke can be wound to fix the pin, why use a
> more expensive correction board? Third, I thought of an
> easy way to double the drive-use 2 driver boards, and 2 sets
> of outputs! Drive board 1 (say a P327 from a WG) is X only,
> 2nd for Y. Feed drive 180 deg out of phase to one input,
> and connect the yoke winding between the 2 outputs. Has
> anyone tried this? I'd like to, but I need a P327 WG
> defelection board. Anyone have one for sale?! The yoke
> would have 2X the "kick" on it, for 2X beam draw speed. DC
> hold current would be the same, but drawn from both
> supplies (+-) equally (at 1/2 voltage each Of couse 2X
> parts=2X chance of failure! How about boosting the voltage
> to the board? The driver bias could be adjusted to
> compensate, and getting hi-power transistors at 6 Amps and
> 200 Volts are possible now.I'm still working on my game
> system-slowly. It will be awsome when done-A modded 19"
> WG with a vector drive board of my own design, with a
> computer driver program/game engine of my own
> design. If I can get a deflection board, I am keen to try
> the board doubling idea and the voltage increase.Keep up the
> stimulating conversation!
> Aaron Howald
> ahowald@w-link.net
>

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