[SunHELP] Sun GDM20D10 monitor??

Steve Sandau ssandau at gwi.net
Wed Oct 27 06:40:53 CDT 2004

>>Does Anybody know what I should do next after I have soldered the 13w3 cables from a sun (sony) gdm20d10 montor to a pc vga plug. When I plug it into my pc the image
>>is half height and keeps rolling form top to bottom. I heard I either need a a sync pulse inverter or use the program power strip to reverse the polarity of
>>the signal? I tried this it makes no difference. If I set the monitor on windows
>>98 and xp to anything other than 85hz refresh rate it all goes flashing and you can't see a thing???
>>Anybody know whats going on??
> There are tiny $20.00 converters for this. And yes, you are having a
> sync problem. PC's have a separate sync line whereas other monitors
> derive sync from the green signal.
> Or something like that.

I've looked into this kind of thing a bit lately. Evidently PCs have 
separate vertical and horizontal sync as well as RGB pairs. Suns (and I 
assume Sun monitors) use composite sync, that is vertical and horizontal 
sync on one wire, plus RGB. Other machines like SGIs, HP boxes, and 
older Macs, put the sync signals in with the green.

There are some circuit diagrams floating around for conversions. I don't 
recall seeing one that'll combine the V and H sync (which is what you 
need to do) but there may be one. You might try these links:


I found I had to do a fair amount of reading to start getting a clue... 
High school electronics was a *long* time ago!


More information about the SunHELP mailing list