Arcade monitor - trouble adjusting game screen to fit vertically on monitor.

[Wyluli]

BACKGROUND - The cabinet has a 25" Hantarex Polo monitor in it.  Using Arcade VGA card with PC, MameWah and Mame .89.

Problem - The monitor works fine, except I can't seem to get my screen adjusted correctly.  The problem is that the picture can not be adjusted all the way to the bottom of the monitor (If I try to move the entire picture up or down, I can move it up, until the picture is partially off the screen, but when I adjust it down, it only goes so far and stops before it reaches the bottom of the monitor). 
I can "stretch" the picture vertically, but if I do this to get the picture to take up the screen, the score and info at the top of the screen moves up off the screen before the picture reaches the bottom of the monitor. 
**note: I don't mind having black borders on the left and right side of the screen (with the old vertical games), I just want the screen to fit vertically (taking up the entire screen top to bottom and still display the scores and info).

As an added bonus, regardless of what you do, the bottom of the game screen appears scrunched up.  As you move up the screen, the picture  "unscrunches" and appears normal.

Example: (wish I had a digital camera).  Say your playing Pac Man.  The bottom of the pac-man maze will be squished. As your pac-man guy cruises thru the bottom part of the maze he shrinks and as he cruises up towards the top of the screen he returns to normal size.

Hopefully someone understands what I am trying to say and can visualize it 

Where do I start troubleshooting this mess?

NOTE: This is mostly prevelent on older games like pac-man and dig dug, etc... It's not so obvious when I adjust the screen (stretch it vertically to fill the screen) and play games like Bad Dudes etc..   

Thank You

P.S. Found a post where someone had the same issue and explained it better, but still do not have a definate resolution to the issue.  Here is how they explained the problem:

The "Vertical position" potentiometer on my monitor is all the way to one extreme but the bottom line of text (or image) of my screen is not at the bottom of the monitor. The bottom of the screen has ~ 1-2" between last line of text and the bottom edge of the tube while the text at the top of the screen is either at or extended past the top of the tube. What could cause this? (It's like I need to just turn the Vertical position pot and move the image down, but like I said it is already at the far extreme.)

If I adjust the height potentiometer so that the top of the screen is still on the tube, the bottom line of text in MAMEWAH and the bottom lines of other images on the screen are scrunched up. I can then use the "Height" potentiometer to fix this, but in doing so, the top of the screen is expanded up past the top of the tube.

[Wyluli]

I have come to the conclusion that maybe part of my problem is adjusting the resolution in the older games (pac-man, dig dug etc..) So I'm trying to use the mame resolution tool.  I have followed the Read me file but when I click on the Test button at the bottom of the resolution screen it brings up the mame dos box and sits for a few seconds and closes out without bringing in the game.

Even if I can figure out the resolution tool (any advice apprecited for this) it still does not explain the squished looking screen at the bottom.  Anyone have any ideas?

Thanks again.

[subcriminal]

The only way to diplay all games properly even with an arcadeVGA is a rotating monitor setup. You will get screen cut on pac man and galaga etc if you have the resolution perfect on a horizontal monitor unless you run top and bottom borders on horizontal games.
Run a 288 line game in the correct resolution and adjust the V gain so it fits the screen then you'll see what I mean.
This is my solution as I hate hardware stretching, missed lines and all that!

[Wyluli]

Could you tell me exactly how to run a 288 line game in the correct resolution?
I'm still having problems with the mame resolution tool (as described in this post).  So right now I guess it is just choosing the resolution on it's own, which works pretty well for the most part except for the problem described.

Thanks

[RayB]

I think the bottom line is that your picture shouldn't be "squishing" in teh first place. How old is your monitor? It might be defective.

[Wyluli]

After reading many more posts etc.. I still have not been able to figure out what is wrong with my monitor.  I still am not sure if it is a hardware issue or a software issue. 
I adjusted my monitor resolution to 640x288 and the windows (windows 98 SE) desktop looks clear and flicker free (thank goodness as my eyeballs were melting  trying to work on this thing).  However, the screen is still an inch or two from the bottom of the monitor.  (as stated before/below) 
"The "Vertical position" potentiometer on my monitor is all the way to one extreme but the bottom line of text (or image) of my screen is not at the bottom of the monitor. The bottom of the screen has ~ 1-2" between last line of text and the bottom edge of the tube while the text at the top of the screen is either at or extended past the top of the tube. What could cause this? (It's like I need to just turn the Vertical position pot and move the image down, but like I said it is already at the far extreme.)"

Can anyone tell me if this is a hardware or software related issue for sure and point me in the direction of a possible fix?

Thank You.

[SirPeale]

Sounds like a cap issue.  I would try replacing all the caps.  And I mean *all*, not just those in a cap kit.

Actually, if you have a cap meter, I'd just go thru them all and replace *just* the bad ones, but I'm betting you don't.

[Wyluli]

Sounds like a cap issue.  I would try replacing all the caps.  And I mean *all*, not just those in a cap kit.

Actually, if you have a cap meter, I'd just go thru them all and replace *just* the bad ones, but I'm betting you don't.

Arg.  I had a feeling someone might say that.  I thought it might be a problem with one of the potentiometers and perhaps it needed replaced.  I wish I had a good book on arcade monitors and pcb's that really explained all this stuff.  I'd really like to learn and understand it all.  Anyhow, maybe I'll check with Bob for a cap kit and remaining caps. 

On the irritating side, for some crazy reason my mame/mamewah setup is no longer working.  The game menu comes up but none of the games will start and the screen shots are not showing.  The only thing I changed was the desktop screen resolution on windows and BAM!  the damn thing stopped working and I have no idea why  .  This is one frustrating  ing project. 

Thanks for the advice.

[pink]

Did you ever resolve this?

I just picked up a Midway Wrestlemania cab to start a mame project on.

It has a Polo monitor in it that does the same exact thing - even on the wwf board, I havent even gotten to mame yet.

The vertical pot is turned all the way but there is still an inch or so of space at the bottom of the monitor.  Ajustments to other settings to try and make it better only seem to result in some variant of a squished picture near the bottom. - basically same problem you (and it appears others) have described.

Anyone who regularly repairs Polos seen this behavior? 

[grantspain]

polo's are known for cap problems, my thoughts are mainly directed to the electrolitic caps or even a faulty/dirty pot.
whatever it is it ain't a big problem to resolve

[pink]

Would those caps be included in a standard capkit for this monitor?

[grantspain]

i work on many polo chassis,i start with all the electrolitics in the power supply and frame circuits(also any near a heat shield),i would guess a standard cap kit would suffice,also worth changing the vert shift pot as a matter of course and checking for cold solder joints/bad connections etc

[pink]

thanks!

[Yanitzch]

I just got a nice Killer Instinct 1 cab with the Polo 25" monitor.  I have also the exact same problem (the image is "squished" on the bottom).

It's weird, the more you go up on the screen, the more space there is between the line.

I am just curious if any of you finally fixed it?  And by doing a cap job or any other idea?

Thanks,
Yanick

[AlexKidd]

Most likely a bad cap/caps

http://www.repairfaq.org/sam/tvfaq.htm#tvvsquish

The poor part of the guts who's job it is to supply the exactly right voltages at the right time to bend the path of the electrons all the way down so they hit the bottom parts of the screen aren't getting the amount of juice they need. The magnetic field created by the yoke that bends the electron's path isn't quite strong enough to do it. Probably some cap in there bleeding out caustic tears of pain trying it's hardest to give the juice but just can't. It almost makes me cry thinking about it.   

[Ken Layton]

The "squishing" problem is called "foldover" and the vast majority of the time it's caused by bad electrolytic capacitors. Hantarex monitors are well known for having tons of bad electrolytic capacitors. Install a capkit right away.

[Yanitzch]

Thanks!  A regular cap kit like the one Happ control sells would be enough or should I change all the caps?  Sorry for asking, I am a real of newbie on arcade monitor...

Yanick

[Ken Layton]

In general a capkit for your particular monitor should the problems you're experiencing. The kits Happ Controls sells should be ok provided you order tyhe correct kit for your monitor. Better kits (more complete and at a cheaper price) are sold by Zanen Electronics and they won't rape you on shipping like Happ does.