problem with arcade monitor

[matz100]

hello  

ive the following problem:

i bought a cabinet and want to use the arcade monitor with my pc in msdos mode. the monitor works with the buildin cardgame just fine. the game connects via a adp-adapter to the cabinet. the monitor has following inputs :ground r g b and sync. so i disconnected the adp-adapter and connected a vga-cable(with these coax connectors) with extra r g b and two sync cables to the monitor. i connected the 2 syncs to the 1 sync on the monitor and the rgb to the rgb on the monitor. all grounds i connected to the monitors ground.

the problem is that i just doesnt see anything on the monitor (its still working with the card-game and the power is also swiched on an i can "hear" the monitor)

i have a matrox mystique graphic card and i used the advcfg programm to test (i choose servral arcade settings 15-30khz)

i also tried powerstrip and a gforce2 with windows ...

and still i dont see ANYTHING on the monitor ....
i excpectet to see just some flickering or anything else


so id be very happy if anyone had some idea to get something visible  ....

 

 
(i just dont know the specs of the monitor ... its from 1984   )

[PacManFan]

Arcade monitors expect a signal from the 0-5v range, Your vga card is outputting 0..1v, try turning up the brightness of the monitor and see if that helps.
-PMF

[matz100]

thanks for the good idea  

but where can i increase the brightness of my monitor?
is there a way to increase the volage out of my vga-card?

[Dak-ak]

brightness is controlled by an onboard dial in the back somewhere...

http://link.mywwwserver.com/~jstookey/arcade/WG_25k7191/WG_25k7191_diagram.JPG

Mine is in a different place... on a little remote control thingy...


To boost your voltage level.
http://www.ultimarc.com/vidamp.html

a possible problem: My monitor is blank if i accidently send it positive sync signals... you need both negative hsync and vsync...

[matz100]

hey nice ideas  

ok next thing i do is to check the voltage ...

i expected that every vga-card has negative output for both syncs ... at last my mystique which is often recommended


ok tomorrow ill try out  

[matz100]

ok i made some mesurements ant the result ist :

the wireing is ok
the vga outputs only 1v
the original game about 4v

so i got to increase voltage ...


thanks for the help

[matz100]

today i looked again and i found out that i realy have positive h and v-sync out of my vga-card ... how can i change this to negative output?

is there a way to do this by software or do i need some hardware solution?

another question: is there any guide to build the vga-amplifier by myself?

confused greetings  

[menace]

Your monitor should have H sync-, H sync+, V Sync-, V sync+.  I hooked my hacked vga cable so that the horizontal sync went to the h sync- and the vertical sync went to the v sync- .  This works fine.  Some monitors may require you to combine the H sync and the V sync from the monitor cable to a single sync input on the monitor (this doesn't seem to be your case)  To build your own vga amplifier look here:    http://www.mameworld.net/pc2jamma/hardware.html

I built it but haven't tested it yet--its fairly cheap to build if you have access to electronic supplies (and radio shack won't cut it on this one)

[matz100]

thanks for the guide ... ill try it


no my arcade monitor has only combined h and vsync ...
and it seems to respond only on negative values ...


ill try mon-arc plus with a vodoo3 video-adapter now ...

ill post the results soon ...
wish me some luck  

[Ken Layton]

It would be very helpful if we knew the make & model of your 'arcade' monitor as there are many different makes & models out there. Not all have positive and negative sync inputs. Some have positive only, some have negative sync only.

[matz100]

unfortunately i dont know the model of my arcade monitor ...
it seems be be from 1984 and theres a card-game running

its labeled with "orion" and seems to be some rare? german custom machine with a adp connector ....

i just took some mesurements again and found out that i was wrong and that the monitor runs with positive sync ...

im quite sure that its the voltage level of the vga-rgb that ist to low for the monitor. the build-in game has about 5v and the vga rgb about 1v  (as aready said here) ....
the sync of the vga-card seems to be nearly as strong as the sync of the build-in game

so im gonna build the vga-amplifier to get the monitor  working  

[Dak-ak]

I would guess that its more likely a sync problem than a voltage one... from what I've read, you should at least be getting a picture from your monitor (although dark) with a 1 volt signal... However, I've gotten the EXACT same thing you describe using positive syncs....

You might try powerstrip or advancemame.. I believe both allow you to specify the polarity of your sync signals.

[matz100]

i did some mesurements again:


with the 2gaphic-cards i used the advcfg testscreen (CGA 15khz)

            arcade_game          vodoo3          matrox_mystique
r          +3v                           +0,1v            +0.1v
g         +3v                           +1v                +0.1v
b         +3v                           +0.1v            +0.1v

sync    +4v                           +5v                +3.5v


i cant really explain the +1v on green at the vodoo3  
and jet i cant get ANY image on the arcade monitor (only with the original arcade game)

strange