Differing Contrast Ratio Between Games Displayed on CRT

[P.H.U.]

I finally have my monitor calibrated and it looks fantastic displaying just Windows and in most MAME games. I am noticing however that some games look terrible with how I have the monitor calibrated. I love old games where the background is just black (Donkey Kong, Pacman, Defender, Galaxian, etc.). I am sure to make the background not emit any kind of light in those games. I want the purest black I can get, so those irradiated phosphors just glow. But games like Killer Instinct, MK3, and a few others just are almost unplayable. Is there anything that can be done here? I want to avoid per game HLSL settings since I am running older hardware and am doubtful my machines will play games smoothly with those settings enabled.

[Calamity]

I've never needed to use different brightness/contrast adjustments for different games. Are you using any video amplification for your arcade monitor? (such as the ones sold by Ultimarc)

[P.H.U.]

It is hooked up through a J-PAC, but I don't have the Ultimarc video amp. Killer Instinct is very dark. Looks terrible. Not using any other amp either. Actually, I only have one J-PAC, the plan is to gut most of cabs for MAME.

Eventually, I will just hook up the PC right to the monitor, with no J-Pac.

[buttersoft]

It is hooked up through a J-PAC, but I don't have the Ultimarc video amp. Killer Instinct is very dark. Looks terrible. Not using any other amp either. Actually, I only have one J-PAC, the plan is to gut most of cabs for MAME.

Eventually, I will just hook up the PC right to the monitor, with no J-Pac.

Doesn't the J-Pac have a built-in video amp?

EDIT: According to Ultimarc's home: yes, yes it does.

[P.H.U.]

Ok, I'll wait for these things to come into the mail then and will hook up the VGA cable right to the monitor with them.

http://www.ebay.com/itm/201456303236?_trksid=p2060353.m2749.l2649&var=500636248037&ssPageName=STRK%3AMEBIDX%3AIT

Hacking my own breakout cables wasn't fun. RGB leads were easy to do. But the other leads were so thin and kept breaking. Not all VGA cables are made the same. Also, I removed the USB connector off the J-Pac which I believe powers the amp. I couldn't get v-hold to stick. But instantly, the monitor darkened. We'll see what happens after those connectors arrive if it makes a difference for contrast/brightness without an amp.

[buttersoft]

I actually found I needed a video amp from VGA to my arcade monitor otherwise the picture was far too dark.

[haynor666]

Can You run game that have some title screens mostly white and see if monitor gets darker on such screens. Good choice are some cave game (cave logo on white screen).

[Calamity]

Also consider posting some pics of the picture you get.

[P.H.U.]

I'll post some pictures this weekend as I travel for work during the week.

[buttersoft]

Can You run game that have some title screens mostly white and see if monitor gets darker on such screens.

I have this problem on one of my CRTs. When the monitor changes to a fully white screen, it stays bright for maybe a quarter of a second, then fades to much dimmer. Any idea what might be causing that?

Soz for potential hijack!

[haynor666]

I have the same problem with my actual TV and was with other one previously. I think it's damaged electronics. I fact I've seen this also on couple other TVs just to connected to PC but as simple television receiver so this does nothing to do with PC or groovymame.

[buttersoft]

...nothing to do with PC or groovymame.

I realise that, yeah. I'm, just looking for an answer

[P.H.U.]

Success! No need for pictures. Let's just close off this thread.

So last week, Calamity asked if I connected my PC to the monitor with a video amp. I connected it with a J-Pac, to which we found has a built in amp. I disconnected the USB cable from the J-Pac, then fired up the cab. The picture instantly darkened and V-hold would not stick.

This week, these came in mail making breaking out the VGA cable and the connection to the monitor easy. I made the breakout connections to the monitor input. Connected the VGA cable to the breakout. Then, I fired up the cab. I got:

• Same dark image
• V-hold was not stable, but wasn't flipping uncontrollably either

After the Windows desktop loaded, I made some adjustments to V-hold and brightness and got:

• Stable V-hold, with just the slightest adjustment!
• A nice bright dimensional image (as in the blacks were nice and deep)!
• And a startling improvement, the blooming whites I noticed before but disregarded were now gone!
• I fired up the dark background old school games and they were just as playable as before, but now the blooming was gone!
• I fired up Killer Instinct and it was perfectly playable. The image didn't look over-toasted with blacks

Long story short, J-Pac's built in amp does impact the contrast between games. Buy these things if your monitor does not need the video signal amplified, it makes the breakout connection easy. Cost less than a breakout cable, or just slightly more than hacking your own, or paying for the shipping to buy it off one of the members here that gives away the breakout cable for the cost of shipping. Saves you time with the numbered screw down terminals. Hacking a VGA cable can be frustrating due to the cheap thin wire gauge used in whatever cable you are hacking.

One more problem solved/lesson learned.

[P.H.U.]

Here is a shot of the breakout board in action. Notice I jumpered pin 13 & 14 to get sync. The breakout board made sending video input to the monitor simple.

[buttersoft]

[brad808]

For jpac pull all those stupid jumpers off, solder pins 13,14 together on the VGA input on the board. This will give you amplified signal, sync, and remove those annoying filters that don't allow you to use multisync monitors on the fly via groovymame.

[P.H.U.]

For jpac pull all those stupid jumpers off, solder pins 13,14 together on the VGA input on the board. This will give you amplified signal, sync, and remove those annoying filters that don't allow you to use multisync monitors on the fly via groovymame.

Actually, in this case, I need an UN-amplified signal. Which annoying filters are you referring to?