Consoleized MVS: picture keeps rolling

mrchafe · Jun 23, 2006

My MV-1F arrived today and so me and a friend have wired up a SCART connector to output an RGB picture so we can use a regular TV. (We're in the UK so this should work)

Amazingly it almost works, except the picture constantly rolls. We've wired it up according to this via a SCART connector, all colours come out okay, but the picture is rolling uncontrollably.

If anybody has any ideas as to how to fix this, that would be greatly appreciated.

Dean · Jun 23, 2006

Try grounding the sync line through a 0.1-50 uF cap. The # does make a difference, so try a couple.

Kunio · Jun 23, 2006

Try it on another TV. There are some TVs in Europe that work only with 50Hz synch and if your MVS is 60Hz, the picture will roll and there is nothing you can do except try another TV. I would try the caps suggested earlier in this thread though. I have never heard of that one before, but if it works please let me know.

Have you been able to run any other 60Hz equipment on this TV before without a rolling picture? Like NTSC SNES, NTSC Neo Geo AES or something?

Adamaki · Jun 25, 2006

Yeah I would say it's the tv that is the problem. I sold a modded aes to a guy a while ago, which worked fine on my tv but didn't work properly on his. He tried it on a different tv and it was fine. Some tv's just don't like 60Hz and it's not always the older models.

mrchafe · Jun 25, 2006

Thanks for all the advice. I'll hook up the MVS tonight to a TV that I know works in 60Hz mode and hopefully all will be well, otherwise I'll try the cap trick and see how that goes. Thanks for your help so far!

(and Adamaki, love the MVS in your sig!)

Stellaking · Jun 26, 2006

Did you get this sorted mrchafe ? I had the same problem with a 2-slot running RGB via SCART and found left to right picture roll on every tv I tested on.

ttooddddyy · Jun 29, 2006

Just for the record.

Sorry-dont mean to split hairs. Accademic really

MVS vertical frequency is actually 59.185608 Hz as opposed to 60 Hz straight as used on a lot of jamma boards

mrchafe · Jun 29, 2006

Bad news I'm afraid - still no fun, even though I've now tried connecting it to two TVs that I know work happily with my Dreamcast and GameCube when set to 60Hz mode. One of them displays on-screen that it's in RGB mode, but displays no picture; the other just keeps on rolling.

I might try the capacitor if I get the chance, but does anybody see anything I'm doing that seems silly?

Witchboard · Jun 29, 2006

D-Lite said:
Try grounding the sync line through a 0.1-50 uF cap. The # does make a difference, so try a couple.

I'm also having a similar issue. Are you suggesting that you put a cap in the sync line, or the ground line? I don't understand, "grounding the sync line." Sorry if I seem dense, but I thought I would ask for clarification. Mine is not a supergun, but I have it hooked up to a Sony PSOne LCD.

mrchafe · Jul 1, 2006

If I sent my current JAMMA harness to one of you on the forums, would anybody be able to take a look at it / test it with their MVS and see if they can figure out the problem? I'd be more than happy to pay shipping etc. if somebody could kindly spare the time to give it a look-over.

mrchafe · Jul 2, 2006

Bad news I'm afraid. We've tried with a 10 and a 1µF capacitor with no real change - a slight change in the pattern but otherwise still no vertical hold. Generally on sync at all.

nagrom · Jul 3, 2006

Do you know if your setup includes a lm1881 circuit ?
If not, maybe you can give a try.

dannywhac · Jul 3, 2006

Dunno if this helps - I used to have problems with the scrolling screen......
I wire it like this (the number denotes the scart pin number):

Red= 15
Green= 11
Blue= 7
Sync= 20
Video Gnd= 17
Audio L= 6
Audio Gnd= 4
Audio R= 2
+5v via a 100 ohm resistor= 16

Hope it works out......think this is ok as it's from memory and I'm at work......

Consoleized MVS: picture keeps rolling

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