Don't want to kill arcade monitor!

[UnclearHermit]

Hi.  I'd posted this question over on my build thread but I think this is probably a better forum for it.  I've got an arcade monitor from an old JAMMA cab and I've had it up and running from a Win 10 machine with GroovyMAME and CRT Emudriver.  Up until this point I've tested with a J-PAC.  I've got an AMD 5450 1GB card connected via VGA and have used a separate LCD panel on the motherboard video output to get things set up, including the fact that the BIOS (technically UEFI) is set to boot from onboard first.  The monitor is moving into my build project and I'd rather not use the J-PAC there because I can then keep it for the JAMMA CAB and also because I have a U-HID for my own build and wouldn't need the J-PAC for anything other than the VGA connection. 

What I don't want to do is damage the arcade monitor, and I've read a little bit about using ATOM-15 in this regard.  What's the best approach here?  Can I just wire a VGA cable directly from my 5450 and take whatever cables are necessary from that to feed the arcade cabinet?  Or does that risk me doing bad things to it.  Would ATOM-15 protect me here?  Any help appreciated!

thanks

[Arroyo]

Yes Atom 15 would help prevent a 31khz from emerging from your computer (to be clear only an issue when machine reboots). 

I think the consideration I’d give is, it’s my understanding that most (all?) arcade monitors are expecting a 5V peak to peak signal from an original Arcade PCB.  The output from the computer is 1V.  This affects the brightness and perhaps the color range?  Your Jpac provides this video amplification as well as preventing the 31khz signal.  I’ll try to find the post that went over this in more detail.

[Arroyo]

Found it:

http://forum.arcadecontrols.com/index.php/topic,162002.msg1707723.html#msg1707723

I think this is a good read on the subject.

[arfink]

Your Jpac should kill the signal if the sync is too high, and should take care of voltage levels and sync polarity for you too. Just go through that and you're good. But FWIW, while it might be possible to blow up your monitor by feeding it 31khz all the time 24/7, I highly doubt that an occasional blip during boot would kill it. I'm not even sure if anyone's made a good explanation of exactly how feeding it the wrong sync would kill it. Most monitors should be robust enough to handle the occasional desync.

[Arroyo]

I'm not even sure if anyone's made a good explanation of exactly how feeding it the wrong sync would kill it. Most monitors should be robust enough to handle the occasional desync.

The HOT (Horizontal Output Transistor) isn’t designed to handle frequencies in that range.  You risk frying that part of the circuit. 

Your point is well taken that the amount of time and frequency that it would occur is probably brief and not that often.  I don’t think there has been any robust testing of this, but it is a good precaution. Also should a part of the circuitry fail there are lots of people who are knowledgeable enough to fix it.

[pbj]

It's marketing guff.

[UnclearHermit]

Yes Atom 15 would help prevent a 31khz from emerging from your computer (to be clear only an issue when machine reboots). 

I think the consideration I’d give is, it’s my understanding that most (all?) arcade monitors are expecting a 5V peak to peak signal from an original Arcade PCB.  The output from the computer is 1V.  This affects the brightness and perhaps the color range?  Your Jpac provides this video amplification as well as preventing the 31khz signal.  I’ll try to find the post that went over this in more detail.

Thanks.  Stuff I need to consider then.  I could stick with the J-PAC although I'll then need to wire up a JAMMA edge board connector just to take the monitor wires.  Or I could try Atom 15 for the monitor protection and then buy the Ultimarc monitor video amp, which would do the same amplification but give me an easy breakout board for connecting to the monitor.  I'm tempted by the second option if I can get Atom 15 working, because that way I get to keep the J-PAC for the JAMMA cab wiring and I can avoid any need to wire a JAMMA edge connector!