Re: SW WG Missing vectors

Dangerwil@aol.com wrote:
>
> All,
>
> I have been tracking this nutty problem for a couple of days now. I have
> a Star Wars that is displaying misplaced vectors.
>
> The monitor is a WG 6100 that has an older tube with a lot of Gravitar burn
> in. The display shows up looking much like a WG K4900 with a lot of
> horizontal curl.
>
> The top vectors, score and shield bar all smear down the screen. I also see a
> waviness to the screen, much like a bad power supply will exhibit on a raster
> monitor.
>
> I have substituted every part of the monitor with a known good one, except
> for the yoke and tube, even the output transistors . I plugged the game
> into another monitor and the screen looked fine.
>
> I guess my tube is toast, but I have never seen this particular fail. Could
> this be a yoke problem??
>
> Any input you have would be a help.
>
> Thanks,
>
> Bill

Ohhh, you got me!!?? That is definitely a strange problem. If the
vectors are actually smearing like running paint, then I would suspect
the tube. I have never seen an XY tube go bad though, but then again I
haven't worked on TONS of vector games, just a lot.
  I really can't even see a yoke going bad. If it did then it would have
to be some sort of short. That would just decrease the inductance and
lower the resistance + running the outputs hotter, maybe misplacing
vectors too. But assuming that the yoke is bad, that would mean that you
probably only have fault in one of the windings. Having both go bad at
the same time wouldn't seem likely since they are in seperate circuits.
That would mean that your smearing or displacement should only be
happening on one axis. Look very closely to see if both are affected or
only one. That is the best way I track down problems with the old XY's.
   Good Luck!

-- 
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Lots of other General Arcade Game info at
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From: "Gregg Woodcock" <woodcock@nortel.ca>
Subject: Re: SW WG Missing vectors
Sender: owner-vectorlist@goonsquad.spies.com
Precedence: bulk
Reply-To: vectorlist@goonsquad.spies.com
Status: RO
In message "Re: SW WG Missing vectors", you write:
>Ohhh, you got me!!??  That is definitely a strange problem. If the
>vectors are actually smearing like running paint, then I would suspect
>the tube. I have never seen an XY tube go bad though, but then again I
>haven't worked on TONS of vector games, just a lot.
>  I really can't even see a yoke going bad. If it did then it would have
>to be some sort of short. That would just decrease the inductance and
>lower the resistance + running the outputs hotter, maybe misplacing
>vectors too. But assuming that the yoke is bad, that would mean that you
>probably only have fault in one of the windings. Having both go bad at
Surely it is not the yoke but I suppose it could be the tube but I
really doubt it since the monitor works fine running other games.
Obvously the problem is in the AVG board of the Star Wasr set!
>the same time wouldn't seem likely since they are in seperate circuits.
>That would mean that your smearing or displacement should only be
>happening on one axis. Look very closely to see if both are affected or
>only one. That is the best way I track down problems with the old XY's.
The displacement is due to too slow a slew rate for the W-G compared
to the Amplifone.  Decrease the X-SIZ and Y-SIZ a bit and that problem
should improve.  As far as shakey video...
TECH TIP from the ATARI FIELD SERVICE DEPARTMENT
STAR WARS Vector-Generator PCB
Shaky Video
   Problem:  Some games may have shaky video after a 15-minute warm-up.
The video will start to shake in the high-score screen.  The words
PRINCESS LEIA'S REBEL FORCE will start to flutter and then worsen to an
up-and-down movement of about 1/8 inch.  In its worst state, the scores
will also move back and forth.
   Solution:  Change the 10K Ohm resistor R83 on the Vector-Generator
PCB to a 20K Ohm resistor.
--
THANX...Gregg   day 214.684.7380  night UNLIST/PUBL   TEXAS NOT CANADA!
              woodcock@nortel.com  or  woodcock@dfwmm.net
*CLASSIC VIDEOGAME COLLECTOR BUY/SELL/TRADE NON-COMPUTER (ARCADE/HOME)*
"If you quote me on this I'll have to deny it; I won't remember because
I have such a bad memory.  Not only that, but my memory is *terrible*."