Composite Sync?? Please explain?

[stuzza]

I've just attached my ArcadeVGA up to my 25" Kortek monitor for the first time today.  I have the R,G, B and Grounds connected to their resptective pins and I've attached the V- and H-  wires to the V- and H- pins on the monitor.  I am able to get a picture on the monitor, although it is very dim and the colours look horrible.  Do I need the Video Amplifier aswell?  The ultimarc website says that the amp will fix a dim display, which seems to be what I'm getting.

They also say "Almost all monitors, even those which have separate V and H sync inputs, will work with composite sync (generally connected to the H input) ".   Does this mean that I should be connecting the V- and H- both to the H- pin on the monitor??  In other posts here I've seen people have done this to overcome problems with V-hold, which is another problem I seem to have for vertical games?

[dabone]

Composite sync means you combine both h and v syncs and input both on one input, the monitor then separates these signals again to use internally.

If you are wiring your own cable, I can't think of a reason NOT to use separate syncs. It's just 1 more wire and then you have the option of using a lightgun.


As for the dim screen, yes the amp will usually fix this. Does the monitor look good with a standard arcade board?

Also, you need to use the avga resolution tool, but to get rid of the vhold problem. (It's not really a problem btw.) is to only list 60hz modes.
You are losing vhold because you have enabled different sync rates out for different screen modes.


Later,
dabone

[MonitorGuru]

Your picture is probably dim if you are connecting an arcade monitor to a VGA output from a computer.  Computers send out a signal in the 0 to .7 volt range, while arcade monitors expect signals in the 0-4 volt or 0-5 volt range.   See the other topic in this forum about amplifying the signal or adjusting the monitor.


You can brighten it up by adjusting the screen control on the monitor (usually the LOWER of the two dials attached to the big black flyback transformer, under the "focus" one), and then increasing brightness and contrast, and if that isn't enough you could play around with the RGB DRIVE controls on the neck board (but I suggest not doing that as you'll then get your color balance off if you don't know what you're doing)


As far as Sync, yes, typically you can get by simply tieing the two wires together to send to a composite sync out of a -H and -V signal. You can also build a tiny circuit to do so in a better way than simply tying them together, but most of the time you don't need to.

[stuzza]

Thanks for the response.  Well removing the non 60hz modes fixed the v-hold problem and the vertical games now hold!  Although now the top and bottom of the Vertical games is cut off?  I think I've read in the forums here that this is another known issue and can be fixed easily somehow, but I can't remember which post this was in?

As for the dim screen and bad colours, I've ordered the video amp and will see if that fixes it.  I've tried adjusting the brightness, but even at max it is not good.

I think the monitor may need to be degaused or something though??  The colours are all washed and there is a blue area in the upper right corner and a green sort of area in the lower left corner of the screen.  I'll try and get some pictures to post.  Can these monitors be degaused easily?? or may there be some other problem?

[stuzza]

One other quick question, my monitors board has 3 pots for R, G, B (at least that's what I think they're for?) I was wondering what effect these have when turned??  ie. what do they change in the way of colour etc..

See pic: