The way to go here is to test the boards outputs directly with a scope
in XY mode. I could also see the jittery X output by just displaying the
X signal on the scope in regular mode, with the game in test mode to
obtain a repetitive signal. The signal should be rock solid in the
latter case, and no jitter is to be observed in XY mode.
When you suspect the monitor, make sure you remount the chassis
transistors using new heat paste. Clean the pins and sockets. Reflow all
solder joints on the amp board. Check the supply rails for excessive
ripple when the game is playing. If you see a lot of ripple with the
vectors being drawn and the transistors have been remounted and the amp
board reflowed, replace the main filter caps on the amp board. So far I
have not had to replace any of those. See one of my previous posts on
how to make the WG6100 amp board bullit proof without buying a LV2000.
On the monitor there is no circuitry that affects pincushioning, it is
an inherent effect of the way the tube and deflection coils interact.
Bad connections on the chassis transistors, bad solder joints and dried
oud filter caps can all have their effect on this, however I would not
expect it toshow up as a pincushioning problem, more so the jittery
display, the more on the extremes of the screen.
- Mendel
On 31-1-2012 21:58, Xyla wrote:
> Well, I doubt it's on the main board, because I have two Major Havoc
> boards that do exactly the same thing. However, I wonder if it is
> something on the adaptor board... I only have one of those.
>
> Nothing on the game boards can explain the pincushioning though...
> I've tried 3 Tempest boards, and it's definitely the monitor doing
> that. There's no jittering with Tempest, but the jittering on MH only
> shows up when the monitor is drawing a lot more than Tempest ever
> does.
>
>
> On Mon, Jan 30, 2012 at 3:28 PM, Mendel Pearl<mypearl@dds.nl> wrote:
>> On my Space Duel, it was the 6012 DAC of the X channel, after replacing the
>> opamps and analog switching IC's. It had the exact same symptoms you're
>> describing.
>>
>> - Mendel
>>
>>
>> On 26-1-2012 15:13, Andre wrote:
>>
>> i would be interested in hearing if you solve this. my space duel has
>> something similar that is best seen on the screen where you can chose the
>> type of game. the scores and ships available shift up and down a quarter
>> inch sort of thing as the game choice is flashing, in time with the
>> flashing.
>>
>>
>> Sent from my Samsung Captivate
>>
>>
>> Xyla<xduval@xyla.net> wrote:
>>
>>
>> Hi,
>>
>> I have a WG 6101 that when I run Major Havoc on it, when the screen
>> gets really full and the vectors are flickering a bit, the vectors get
>> very jittery in the top corners. When there isn't much being drawn it
>> is totally stable.
>>
>> There is also a slight pincushioning... I know it's not the MH adaptor
>> because it can be seen on Tempest. I've tested with two Major Havoc
>> boards (both jitter), and I've tested the same Tempest board on a
>> different monitor with no pincushioning, so these problems are
>> definitely occurring within the monitor itself.
>>
>> I got this monitor recently, and it looks brand new. It was sitting
>> in someone's house for years... has no burn, and there was still hot
>> glue on the flyback controls. I did a full recap and installed an
>> LV2000 lite, and even did the Major Havoc diode mods to the underside.
>> Unfortunately I do not know for sure if these problems were occurring
>> before I did all this... I didn't want to run the monitor for more
>> than a few moments before recapping it. But, I did not notice any of
>> these things happening until after all the preventative maintenance.
>>
>> My first question is, could the MH diode mod be causing any of this?
>> I read that it was unnecessary if you install the LV2000, but I was
>> just being thorough. I figured I'd ask before I undid the mod.
>>
>> Other than that, do these symptoms sound indicative of anything else?
>> I did not replace any of the T0-3 transistors... maybe I should? But
>> again, I did not notice any problems before the work I did on it.
>>
>> Thanks for any assistance.
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Received on Tue Jan 31 16:26:34 2012
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