I just can't calibrate this arcade monitor!

[veggav]

So long story short:

Got myself an EAGO 29 to 38" arcade monitor chassis.

I had an Gradient TV of 37" with a JVC CRT.


Hooked both together and boom the image was working and seemed awesome wait yet....
I'm using it to hook all my RGB consoles with an adapted scart connector I made. Since arcade uses R G B and Sync the same as most retro consoles it worked.

Now.. I can't calibrate.

When I get the image to be bright as I would like, the black is washed out with tons of white on it.

This is basically my main problem.


When I get the black areas to stop showing dots, lines, or anything that shouldn't be there, the image is too dark.
When I fix something the other side breaks it.

I'm using the XRGB Mini Sega Genesis ROM with my Everdrive so it can display the correct test patterns.

I've tried following several tutorials but they all end up not working.

http://wiki.arcadeotaku.com/w/How_to_Correctly_Set_Up_Monitor_Colours_and_Brightness

This is the best I've found but still it does not work.
When I start to raise the RGB Cut off from minimum those while lines start to appear and several other things don't work as expected following this guide.


After all the afternoon trying to calibrate it I got a nice, color correct image BUT the white screens like the Playstation boot screen or the SEGA logo with white background seems dull and not bright at all.


So how can I still have real blacks and good whites on an arcade monitor?

[lilshawn]

don't forget, you are looking at a CRT, not a high definition display. our vision has been sullied by super bright plasma displays. we have forgotten what an arcade screen is supposed to look like.

the main problem is you have a universal chassis on a random tube. what you will probably need to do is turn up the drive on the color guns to get the image a little richer. but first you need to set everything up.

your first step is going to be to set your brightness/contrast/black levels to the middle (halfway point).

next, you will want to display a black screen with nothing on it. turn up(or down) the "screen" control on the high voltage transformer till it just starts to turn gray, then turn it back a little. this is going to set your screen volts properly.

then, display a gradient pattern something like this:


adjust your red green and blue drive so the white is white and the red,green,blue is nice and bright, but without causing the black to start turning color or the bars to start "bleeding" out of the squares or bars. sometimes you need to switch back and forth between bars and black screens to see if the black is getting tinted by the colors.

on the gradient, adjust the "cutoff" to match any color that doesn't have a cutoff or adjust them so they look the same. (some chassis preset one color and you have to adjust the other 2 to it.)...

the cutoff is going to adjust how quickly a color rolls off to black in the gradient. too high and the color stays on too long (most of the color bar shows as bright) too low and the color rolls off to black too soon. (the first few colors are bright then it drops off to black).

make sure your whites stay white. take a few minutes away and come back to it. you eyes will get used to a color tinted white. stepping away for a while will refresh your eyes. otherwise you'll look at it later and wonder why the white is all green.

that should get you pretty close. Be warned again, you are looking at an old school CRT, it's not going to have a million to one contrast ratio like todays high definition TV of today do... it's more like ten thousand.

[veggav]

Thank you for taking the time to help me out, I really appreciate it.


I need to understand the terms in relation to the knobs I have here.

I have the following here:

R G B gain = is this contrast?

R G B BKG (I believe this is called background those are on the yoke board on the beck of the CRT) = is this R G B cutoff?

Brightness = brightness

and on the flyback I have screen gain.
So all I have here are 4 settings.

"your first step is going to be to set your brightness/contrast/black levels to the middle (halfway point)."

So I set to 50%: brightness, R G B gain and what would be black levels? Are those R G B background?

"adjust your red green and blue drive"

What would be the drive? Would that be gain?

"on the gradient, adjust the "cutoff"

Are those the adjust on the neck of the CRT? The  R G B BKG?

I think I just need to match the terms to follow your instruction to the core

[lilshawn]

some of these chinese companies use terms pretty loosely. in your case i believe the gain affects the input, this is probably down on the main board? if it is it's not what you are looking for. the color drive should be on the neck card too as well unless it's been remotely controlled.  what we want is the output side where the transistors on the neck card actually drive the color guns.

do you have an exact model number for the "EAGO" (EYGO  ) chassis? then i can look up a schematic for it and let you know a little more. I'm pretty sure they are the same manufacturer as Wei-ya chassis.

but my best guess:

R G B gain if it's on the input side (from your game board or computer) adjusts the color input signal.

R G B BKG is probably your cutoff but depending on how it's wired up it may be drive and cuttoff combined control. or just a drive. 

brightness is probably brightness  but brightness is sometimes called "black level" which is why I included it as well.

on the flyback is screen - yes, this adjusts the "screen voltage" this is the adjustment for the 1000's of volts used to make the picture. there should be a focus as well on there too. you shouldn't have to mess with the focus but sometimes it needs a tweak.

[veggav]

Took picture of the adjusts on the board:









I've tried today to calibrate and when I had in mind I was able to get a nice picture I had a different problem:
When the screen had tons of bright things everything were fine but if the screen had just a text and a box on the bottom the color didn't show up.

An example is the Mega Everdrive menu that I had this.


This were followed by colors taking too much time to move on the screen. Going from a bright to a dark and from dark to bright would seems the screen was self adjusting and taking a few miliseconds to do so.

I really need a bulletproof way of doing this, like a method because guessing on test patterns isn't working

[lilshawn]

I looked around the background of your photos there...looks like you are in the UK. (some kind of adapters and transformers going on there in the corner of the pic and a previous mention of SCART) Are you converting 220v to 110v to run the chassis?

if we can grab the model number of the chassis i can try and find out more information. you don't even need to convert the power 110/220v on some chassis, they do it automatically.

EAGO is not a common chassis where I'm from (north america) I'd like to find out some more information about it before we both get frustrated because of a tiny little detail got missed.

I googled up some pics of the  "Mega Everdrive" cart menu...Iv'e never seen or heard of it before so i'm no real help there. BUT....from what i can see there is white text and yellow text for the menu items. you are saying that the yellow text is just showing as white? or is it something else the matter.

pictures are worth a thousand words. maybe even a video posted to youtube if you have the ability.

from the pics you posted it looks like your "R G B bkg" adjustments are color "drive" adjustments.

the RGB gains appear to be on the input side. Not really common except on adapters.


I know you "long story short"-ed your situation there, but maybe it's best to blast it all out.

how did you get to where you are? you are hooking up consoles via SCART cable to a arcade monitor chassis, i get that part... so that chassis must be "standard" resolution? (15khz 320x240? ). Any reason you couldn't have used a television with a SCART port on it?

sorry for my ramblings.

[veggav]

No problem LilShawn.


I'll try to explain it all. I'm from Brazil and we don't have scart TVs here. The best we can get is s-video or RGB converted to component on some high end CRT TV. I used to had that, RGB to component using a Sony 38 inches CRT flat screen the image was awesome but I wanted to get true RGB.

So I had this Gradient tv from my uncle here and it has only s-video input as the best connection possible. It's a 37 inches Gradient tv a very nice piece of hardware. So I started to think it would be possible to use an arcade monitor to have direct RGB with it. It worked, kind of.. as you can see I can't get things to work out here.

The transform you saw is a 110v to 110v isolated transformers of 1000 VA. I use another one of 500 VA 110v to 100v to power up my consoles. Basically this transformers remove interference from the electric power that runs on my entire house and throws a very clean one to my consoles. The consoles are isolated from each other using a individual power switch stripe.
The transform also ensures I won't take any electric shock when touching the chassis since it's isolated.

The EAGO monitor is a generic 53210 model. You won't be able to find much about it


The Mega Everdrive is just a ROM loader for the sega genesis, since this was the only system I've found roms with test patterns that's the one I'm using. The same problems affects the super nintendo, the dreamcast, the ps2 and so on.

Since I'm trying to tweak this for a few days I got several results but it all ends up with a few problems (those do not happen at the same time but I managed to have all of them):

Image stays too long, if I switch from a screen with a menu to a black screen I can see the text on the other screen for a second or I if I display a color ramp I can see if getting painted on the screen from right to left. From lighter to darker.
I believe this problem is also causing the screen to shrink and inflate. I switch often from the menu that is completely blue to the black screen with the R G B and white test color pattern. During the switch, with colors too high I can see the image self adjusting. I can see the corner moving on the blue menu screen.


During another attempt this ROM has several test patterns one of the tests is a gray ramp that has black bars going to white, from left to right on the upper part and from right to left on the bottom. Same image, just mirrored.
I believe this is my main problem, when I set the screen gain with brightness so I can see the almost black bar and this gives me a picture that I can see all the details this at the same time gives me a washed out black. if I play Pac-Man the playing field is all washed. The Mega Everdrive menu that should be back has that white veil.


And the final problem that I've faced is running a test that has a 100% white square on the middle of the screen. If I press A the square goes from 100% to 80% and so on, until 10% light. If I don't see screen gain correctly or brightness when I switch to a lower intensity white square all the rest of the screen starts to dim. A white 20% light square on the middle of the screen would give me a gray surrounding with clouds on it white a 100% white can give me a pure black. This is only running the tests without touching the knobs. There's a point with brightness and screen gain that it stops but again the image lost it's details and it's too dark.



I can upload videos to youtube, this is no problem for me. If there was a method like the tutorials I've seen I could show you in a video what the problems are.
Like the tutorial I've posted on the first post of this thread. When I start to turn the cut-off from 0 to show the colors across the pattern I start to see the white lines cutting the screen. I believe it's called rasters.

So if I have a method I could apply it here and record it. I believe the way to find the right spot of screen gain is to turn everything off, set everything to 0. R G B BKG on the neck board, brightness and the R G B Gain, everything to minimum. Than raise the screen gain a little bit till you see the rasters and then put it back a little bit so the screen becomes black.
My knobs don't have the middle point mark so that's why I was attempting like this.
Still no success. 

[lilshawn]

The EAGO monitor is a generic 53210 model. You won't be able to find much about it

so far the best i've come up with is it is definitely a wei-ya chassis. Wei-ya makes all sorts of chassis under a bunch of different names. it's just a matter of trying to match it to a wei-ya chassis. could you get a top down shot of the chassis and upload it here? Just a shot of the overall board is fine. Just so i can compare the parts locations and match it up.

Image stays too long, if I switch from a screen with a menu to a black screen I can see the text on the other screen for a second or I if I display a color ramp I can see if getting painted on the screen from right to left. From lighter to darker.
I believe this problem is also causing the screen to shrink and inflate. I switch often from the menu that is completely blue to the black screen with the R G B and white test color pattern. During the switch, with colors too high I can see the image self adjusting. I can see the corner moving on the blue menu screen.

this is called "bloom" it's a common thing with CRT's, the high voltage used in the production of the image (called B+) isn't regulated (at least not well), so it varies all the time depending on the load. if you display a lot of white, the voltage dips down a few volts (maybe 10 or 15 volts). This causes the voltage used around the rest of the system (horizontal and vertical deflection) to dip down to as well. this in turn causes the picture size to change slightly.

likewise when the image on the screen changes to black the B+ spikes back up again and the higher voltage causes the horizontal and vertical deflection to change again, this time bigger (since there is now more voltage)

not much you can do about it. It's been around as long as CRT's have been around. Higher end CRT chassis use a feedback system to monitor the B+ voltage to keep it at the same regardless of how much load is on the B+. with these systems you don't notice much bloom because it's more constant.

During another attempt this ROM has several test patterns one of the tests is a gray ramp that has black bars going to white, from left to right on the upper part and from right to left on the bottom. Same image, just mirrored.
I believe this is my main problem, when I set the screen gain with brightness so I can see the almost black bar and this gives me a picture that I can see all the details this at the same time gives me a washed out black. if I play Pac-Man the playing field is all washed. The Mega Everdrive menu that should be back has that white veil.


And the final problem that I've faced is running a test that has a 100% white square on the middle of the screen. If I press A the square goes from 100% to 80% and so on, until 10% light. If I don't see screen gain correctly or brightness when I switch to a lower intensity white square all the rest of the screen starts to dim. A white 20% light square on the middle of the screen would give me a gray surrounding with clouds on it white a 100% white can give me a pure black. This is only running the tests without touching the knobs. There's a point with brightness and screen gain that it stops but again the image lost it's details and it's too dark.

your input signal might be a little weak, your RGB gains should (i think) be turned up to maximum (provided there is no amplification being done to the input signal.) i'm not sure what the signal level of SCART is but most arcade monitors require a 5 volt signal level. if SCART puts out a lower 1 volt signal level, this might be the issue. Some monitors can accept a low signal input. A quick google search didn't net me any concrete info regarding this. As i mentioned earlier, I live in north america, and as such we never adopted the SCART format on our video sets here, so I don't know much about SCART.

Like the tutorial I've posted on the first post of this thread. When I start to turn the cut-off from 0 to show the colors across the pattern I start to see the white lines cutting the screen. I believe it's called rasters.

So if I have a method I could apply it here and record it. I believe the way to find the right spot of screen gain is to turn everything off, set everything to 0. R G B BKG on the neck board, brightness and the R G B Gain, everything to minimum. Than raise the screen gain a little bit till you see the rasters and then put it back a little bit so the screen becomes black.

yes that's a good start.

[MonMotha]

SCART is your TV industry standard 0.7Vpp signal levels.  If there's embedded sync on green, that'll be 1Vpp to account for the sync.

Cranking the RGB gains up to compensate can have other issues.  The amplifiers are often not designed for that and do weird things.  You'll probably get a much better image if you use a video amplifier intended for this application as essentially all standard res arcade monitors expect 3.3-5Vpp signals.

[veggav]

Hey MonMotha, do you know if there's any ready to buy scart rgb amplifier?

I've used in the past the THS7314 to amplify the RGB while doing the Nintendo 64 RGB mod. A friend of mine build me an RGB amplifier for the Turbo-Grafx for this mod. Still I don't think this is what you are talking about.

Do you have more info on video amplifiers for scart input?


--------------------


@LilShawn, I'm going to do a video tomorrow showing the calibration process and where it fails.

[MonMotha]

All the ones I know of have HD15 ("VGA") inputs and expect TTL sync.  SCART obviously is its own connected and uses CVBS for sync (which, depending on how you're connecting things, may partially explain your difficulty - a picture really is worth 1000 words in these cases).

[veggav]

Update here:

I've contacted Tim the creator of this piece of hardware


I contacted him about the problems I'm having and that's what he said:

Yes, this is exactly what the SCART To JAMMA Adapter is for! It's designed
specially for game consoles. There is indeed a video amplifier inside
which be adjusted to suit your monitor (up to 6Vp-p is possible). Any
console connected via RGB SCART cable will look as good as a arcade PCB
does on the same monitor.

The Adapter can be used directly with the monitor (no need for JAMMA
harness). The R/G/B/CSYNC outputs are available on the blue terminal
blocks near the JAMMA card edge. A 12V DC power supply is required too.

I've ordered with the fastest shipping since he's not able to ship with Fedex, so EMS it is.
Anyway, since Brazil sucks it will take at least 2 weeks to arrive.

I'll post here my tests.



----------
One more thing, I've received an arcade PSU. So now I can power up my super gun. I'll be able to test my CPS2 boards on my TV/Arcade monitor to check this vpp theory.
I'll let you guys know.

I need to solder a few pins for the PSU to work.

[lilshawn]

hmm. interesting. looks like maybe an lm1203n video amp.

I suspect you will be pleased with the results.

now you'll have to mess around with the monitor adjustment settings again 

shouldn't be too bad though once you get the proper signal strength going to the monitor.

[veggav]

Hey LilShawn and everybody that might understand CRT better than me.

Today I took my supergun out of the box and fired up my cps2 x-men vs street fighter.

I did several tests and indeed arcade boards seems a lot better.
But one thing still annoys me.

I took several pictures to let you see the problem. All pictures were taken with the same calibration, same cut off, same everything.
The thing is, same images that have dark background will show fine and some don't.

Since a picture says more than a 1000 words:

awesome picture during gameplay




now the problem:
title showing ok:


problem:

the screen seems to drive it's brightness by itself.



fine:


washed background again:



What do you think causes this? Low screen gain, high screen gain?

[lilshawn]

either your screen control might be a bit too high or your color drive is too high. all that text should be a blue color. it might be your pics, but yours is bordering on nearly white.

[veggav]

either your screen control might be a bit too high or your color drive is too high. all that text should be a blue color. it might be your pics, but yours is bordering on nearly white.

I'm using the brazilian cps2 board so the text is kind of purple/pink.

Hey LilShawn I think I nailed it.
I was trying to have pure black on the background because I was watching too close the screen.

If I understand it right, I SHOULD see the scanlines even on pure black screens, right?
When I reduce the cutoff too much (the controls on the neck board) I can get pure black background but I start to loose details, that was my first and main problem.

I took a picture of what I'm talking about:


If reduce it too much I'll loose that last square on the color bar.
The cps2 color pattern isn't the best. I have a konami board that has a much scaled color bar that shows the impact of twisting the cut off.

Putting it simple, should I be aiming for a pure black background or should I see scanlines on black background?
If looking at the screen far away, from the couch, the scanlines just will show as a grey background.

[lilshawn]

i wasn't sure about the brasil version. my MAME romset is quite old and none of the regions work on this game. guess i should update sometime.

ideally you want no scanlines on a black or "no signal" screen...but like you said, you are going to start looking deficient in other areas, you have to compromise in others and achieve an even balance.

I think you are as close as you are going to get with that pic... don't forget, you are dealing with old technology. you aren't going to get razor sharp 100% pic here. especially since that chassis wasn't made specifically for that tube.

[veggav]

Yeah, I think that too. Now I need to wait for my rgb amp to arrive.

I would like to thank you LilShawn. Thanks for using your time to reply here

[MonMotha]

Not only are you dealing with old technology, you're dealing with a set that has some hours on it.  The tubes do wear out...

Ideally, a no-signal or fully black screen is indistinguishable from the set being turned off.  In practice, a little black level creep is unavoidable to get decent low-intensity gray performance, but you should not be seeing retrace lines on a black screen ever.

Also, these things don't get nearly as bright as you might want unless you've got a very late model tube with little time on it.  A modern LCD monitor, especially with LED backlight, will easily be brighter than this CRT when properly adjusted.  You may be overdriving the tube (turn down gain/contrast) and overloading the power supply.

[lilshawn]

we still havent got a shot of the monitor chassis yet.

you may not even have to use an isolation transformer if the chassis has an SMPS power supply.

if the power supply uses a boost type regulator, you need to isolate it.

i would not use the bigger transformer. that one, even though it may have a 1:1 isolated input, there is a whole other mess of wires that would be better  not to have to deal with. the smaller transformer is probably fine.