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Sony GDM 1950 Fixed Frequency Monitor

 
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John
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PostPosted: Wed Jul 21, 2004 6:28 am    Post subject: Sony GDM 1950 Fixed Frequency Monitor Reply with quote

Hi guys
I have tinkered for quite some time now with my old Sony GDM1950 to get it to work with
the Matrox Millenium II card, with no sucess. The monitor has separate horizontal & vertical sync inputs.
But the vertical signal doesn't seem to be recognized by the monitor, because the picture
slowly rolls vertically up or down. It obvisoulsy doesn't matter wether the Vertical sync
input is connected or not.

Somehow the V-Sync doesn't seem to go thru the input circuit of the monitor.
Are the pulses of the Matrox card to narrow?
Any ideas how I can solve this problem?

Many thanks for looking into the problem.

Hans
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Rich
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PostPosted: Wed Jul 21, 2004 6:29 am    Post subject: Reply with quote

This monitor requires bot the H-Sync and the V-Sync to be the correct way up ie +ve going or -ve going, I can not remember which way up they should be or even if they are both the same. I would guess that they should both be -ve going as this was the standard for fixed frequency monitors. I used to have a test program that could set resolutions and H & V sync polarities independantly this is how I found this out.
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MIke
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PostPosted: Wed Jul 21, 2004 6:30 am    Post subject: Reply with quote

Please make sure the vertical signal is sending out from Matrox Millenium by oscilloscope or counter.
If vertical sync exit and still but not recognized by monitor. It is possible because the wrong polarity.
I can design a low cost converter circuit on your monitor input stage. Your monitor will then accept either positive or negative input Sync.
with this converter circuit
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Richard+B
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PostPosted: Wed Jul 21, 2004 6:30 am    Post subject: Reply with quote

Hi the GDM1950 requires the sync to be the correct way up whereas your card changes these depending on the mode, I am guessing this, but most fixed frequency monitors required negative going pulses for both H & V syncs. I have had these monitors working off a PC using a test program that allowed you to changed the sync polarities. Rich
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Sugil
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PostPosted: Wed Aug 04, 2004 1:04 pm    Post subject: GDM1950 Reply with quote

I designed a little circuit that changes the horisontal and vertical pulses to the right modes regardless wether the input is + or -.
You have to have both H and V good in order to get sync.
Give me an email adress and I'll send you the drawing.
[email protected]
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