Vertical Sync pot extreamly touchy, Wiring from vga computer to Arcade monitor?

[bradley1023]

Hello all

Been a while since i posted, i was the one trying to connect a computer via scart on a Loewe calida 5155. And with the failure of being able to get the screen to sync i bought a proper arcade monitor. The cocktail project has gone some under major work over this school holidays and its just about done. I will post photos

After installing the monitor (the right way up when the top is folded to the floor), i noticed that all the games, interface everything was the wrong way around, i thought that will be a simple fix by simply rotating the computer screen, you know with function CRTL, ALT, arrow key. But it turns out that with my particular old graphics card (Radeon 9200) and the computers operating system (Windows XP SP3) the rotate function is not possible  . I researched that many fixed the problem by simply installing windows XP SP2 but that's some mucking around.

So i thought it was easy enough to simply rotate the monitor itself 180' so the anode suction-cap sits towards the floor when its folded down but being a cocktail cab the screen will be facing up so i didn't think there would be much of a problem. I tested it while the top was folded down so i could change the pots but the colour now seems to be all wrong and slowly the screen moved to one side until it split the screen. and one half of the image is in one top corner while the other half is in the opposite bottom corner and it changes the colour dramatically. At this point i immediately turned off the monitor. then attempted it in the upright position but the same happened.

Degaussing the screen does effect the colours but it didn't seem to want to come right and it dosnt explain the split screen issue. So would ultimately trunning the screen around have these effects. In my research i have now learned that flipping wires to the yoke could fix my problem but being an entire newbie to all this i thought i should consult you guys first.

[grantspain]

horizontal hold is probably just out and try rotating the machine for the gaussing issue

[bradley1023]

Hi grantspain, thanks for the reply, well it was in fact just that, the horizontal just getting out and in degaussing the screen the colors do eventually come good. I am still left with one problem though.

The vertical sync is extremely touchy, moving the pot slightly either way reverses the direction of the rolling almost instantly. It is possible to get it to hold eventually but after its turned off it either comes back on in a different position or is rolling slowly. I am connecting the monitor via a computer which is wired through the vga cable. I have been reading that this problem is almost directly related to how the sync wires are placed. right now the horizontal sync from the vga cable is wired to horizontal sync to the arcade monitor chassis but i was told not to wire the vertical sync from the vga cable to the chassis. should it be shorted with the horizontal sync or should it be separately wired to the vertical sync on the chassis?

[grantspain]

you could try joining the vertical and horizontal sync wires or try a 5k resistor from vertical sync pin to video ground on the video input connector of the chassis

i only work on priginal arcade stuff so not familiar with res software on pc video cards

[bradley1023]

So will attempting to joining the vertical and horizontal sync from the computer to the Horizontal sync to the monitor chassis pose any threats to the monitor at all do you know, i am unsure of this and really don't want to damage my monitor.

[grantspain]

So will attempting to joining the vertical and horizontal sync from the computer to the Horizontal sync to the monitor chassis pose any threats to the monitor at all do you know, i am unsure of this and really don't want to damage my monitor.

never seen a monitor damaged by linking sync signals in 30 years

what is you actual monitor make/model as some older chassis have sync mods to counter this issue

[bradley1023]

Well the chassis is brand new and the arcade tube is meant to be old not sure how old. An arcade repairman bought the new chassis and had the tube spare and he set them up for me. He dosnt know anything about connecting a computer to an arcade monitor. He's only ever used real deal boards. here some photos i could find of numbers on the tube and chassis. Last picture shows the whole chasiss which might be helpfull for identification i couldn't find anything on the JCE-20A number.

[Ken Layton]

That's Joey at Jomac in Australia:

http://www.jomac.net.au/

[bradley1023]

Just like to say i fixed this simply by tying the vertical and horizontal sync wires from the vga together and connected it to the horizontal sync input on the chassis. Thanks grantspin