"Overscan" problem with CRT Emudriver and a Sony CRT

[Monkee]

Hi all,
I'm having a little problem. I'm using the CRT emudrivers to play groovymame on a old Sony CRT in 15Khz and all my games are cropped on each edges of the screen. But even under Windows, I can see that the edges of the desk (in 640x480) are not in the screen.

When I plug my computer to a LCD then everything fits (even with the same resolution).

It really feels like I'm having a overscan mode in 15khz, does someone knows how to fix that?

Thanks.
Monkee

[Paradroid]

You simply need to adjust the horizontal size (width) of the picture using your TV.

Depending on the vintage of your TV, you will either have a Service Menu setting for this or an adjustable potentiometer inside the TV.

You can find the service codes (to enter the Service Menu) for most TVs quite easily on the Web.

Failing that, you could try to achieve the same result by changing your GroovyMAME monitor specs but it makes more sense to tweak the TV first.

[Monkee]

Thank you paradroid, it's probably a potentiometer for this tv because it's pre 80s.
But i also use this tv to play video game consoles (and I have no problem with the image in this case) so I have to change the tuning every time I will switch between those two systems, no?

Also what about the vertical size?

[Paradroid]

Ah, okay. In that case, if you're happy with the width and position for your consoles, you'll need to tweak your GroovyMAME monitor spec line.

Search the forum. This kind of thing has been discussed numerous times before...

[Monkee]

Ok I will. Sorry for opening a thread about that if it was discussed before, I didn't thought it was about parameters in the beginning.

[Calamity]

Hi Monkee,

Bear in mind TV's are adjusted in factory for an important degree of overscan. Consoles already take this into account. On the other hand the presets we use in GroovyMAME try to maximize the use of the active video in for arcade monitors. This involves adjusting your monitor/TV for zero overscan. But if you want to keep your current adjustment for consoles, then you need to compensate for the "built-in" overscan by adding bigger borders to video signal. This is done by increasing H front & H back porches in the crt_range line (mame.ini). Notice that vertical overscan can't be fixed by software: http://forum.arcadecontrols.com/index.php?topic=134915.0

[Monkee]

Hi Calamity,

Thank you for those clear informations, I'm a bit to afraid to open my Trinitron so I will check out what I can do with mame.ini. 

[arcadepcnut]

Hi all,
I'm having a little problem. I'm using the CRT emudrivers to play groovymame on a old Sony CRT in 15Khz and all my games are cropped on each edges of the screen. But even under Windows, I can see that the edges of the desk (in 640x480) are not in the screen.

When I plug my computer to a LCD then everything fits (even with the same resolution).

It really feels like I'm having a overscan mode in 15khz, does someone knows how to fix that?

Thanks.
Monkee

Monkee what was the ulitimate solution to this?
I have tweaked some setting in my sony service menu. I have another post here regarding this issue and no one has responded. my desktop is off. mame is off. frontend is off and all games are off. there is about 2" of black on left side and on right side and top and bottom is cut off and the hsize and hpos wont move the picture anymore to the left in the service menu.
if this can be fixed in mame and all mame games its ok that the frontend and desktop are off. ive been searching for days to resolve this issue and finally found your post.

[Monkee]

Hi arcadepcnut, the tv you got has a service mode wich is completely different from mine. The tweaks on mine have to be done directly on the hardware so for the moment I didn't change anything. Concerning your problem of everything off though, it could also be the drivers or software related, you should wait for Calamity or another expert to help you because I cannot.

Sorry man.