Followed the instructions, but still no picture.

[SirPeale]

Following the instructions on the PC-->JAMMA website:

http://www.mameworld.net/pc2jamma/pc_arc3.html

I took an old monitor cable, stripped off the ends, and wired it to an arcade monitor I got some months back.

The monitor is known working, but when I power up, I get a black screen. It glows faintly, but that's it.  No picture at all.

Am I supposed to connect the red, green and blue grounds up, or can I just use the sync ground?  That's the way I have it now, just the sync ground.  I hooked the red ground up to see if I would get any picture, but it didn't do anything.

[bloodyviking77]

might be that you need to boost the signal being output by your card.

Some monitors (Hantarex?) accept the lower levels (<3v) output by standard vga cards. Others need  around 5v.

Ultimarc's video amp (and there are schematics to build your own out there somewhere - don't have a link right now) boost vga-level signals to (I think) 5v, which AFAIK  is what most gameboards output.

[SirPeale]

I had thought I would get some picutre, albiet very dim.  That's what I have read, anyway.

[SirPeale]

Since I have no skillz for reading schematics, I guess I'll just go get a J-PAC.  Too bad they don't sell these amps anywhere that I can find, that's all I really need.

[menace]

I hooked up ALL the grounds together and my pc to arcade cable worked ok.  I would also think you would get some picture albeit dim--maybe your specific monitor has a threshold that needs to be reached before it will display a picture  what kind of monitor is it?

[SirPeale]

Some no-name thing.  Got it for free, all I had to do was pick it up.

I've got a WG downstairs, but I really didn't want to pull it, that cabinet has it's own purpose, and I don't want to separate the two.

[Lance]

Following the instructions on the PC-->JAMMA website:
Am I supposed to connect the red, green and blue grounds up, or can I just use the sync ground?  That's the way I have it now, just the sync ground.  I hooked the red ground up to see if I would get any picture, but it didn't do anything.

I'm pretty sure you need to wire in all the grounds.  From the FAQ:

"Don't forget to wire in all the grounds, wire the first one to Video Ground on the JAMMA fingerboard, then solder a short wire from this across to one of the Ground pins on the fingerboard. This just makes sure all your grounds are common."

Also perhaps your monitor is expecting composite sync?  If that is the case you can try combining your horizontal and vertical syncs together.  

lance

[SirPeale]

I'm pretty sure you need to wire in all the grounds.  From the FAQ:

"Don't forget to wire in all the grounds, wire the first one to Video Ground on the JAMMA fingerboard, then solder a short wire from this across to one of the Ground pins on the fingerboard. This just makes sure all your grounds are common."

Also perhaps your monitor is expecting composite sync?  If that is the case you can try combining your horizontal and vertical syncs together.  

I did wire them together.  I also tried putting all the grounds together with no joy.  I'm guessing it's because of the low signal.  C'est Lavie.  I'll just get a J-PAC.  More than I wanted to spend, but...

Also, I hadn't intended on using a JAMMA interface, but I guess I will now.

[bloodyviking77]

are you sure its worth buying a jpac peale?

byo amp = http://www.mameworld.net/pc2jamma/hardware.html
(looks relatively easy if you are handy with a soldering iron - but i haven't priced up the components)

jpac (PS2)from ultimarc = $57 + $12 shipping =  $69

video amp from ultimarc =  $15 + $7 shipping = $22
http://www.ultimarc.com/vidamp.html


Edit by moderator: fixed URL

[SirPeale]

1) I saw this.  I can solder (finally!  Just took practice) but this diagram is tricky.

2) More than I wanted to spend, but I'm going to need another encoder anyway.  I've got three cabinets right now, and I only have one encoder.  Two of them are JAMMA cabs.

3) I didn't see this one!  Only problem is with the +5v, and that's not really a problem, I could just run it from the PS.

[SirPeale]

Here is a question.

http://www.mameworld.net/pc2jamma/pc_arc3.html

Says here that pin 9 there is naught; on Ulimarc's site he says pin 9 puts out +5v.  I'm guessing the cables he provides has this pin?  I ask because I'm looking @ a VGA cable now, and there is no pin nine there.

[bloodyviking77]

on Ulimarc's site he says pin 9 puts out +5v.  I'm guessing the cables he provides has this pin?  I ask because I'm looking @ a VGA cable now, and there is no pin nine there.

yup, just checked the cable that came with my ultimarc amp, and pin 9 is connected and all works great.

I think the "old" vga standard was for no connection on pin 9, but there is now +5v on pin 9 on most (all?) vga cards.