supergun pvm help

SudoShinji

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I bought a vogatek mkiv that came in today and hooked it up to my pvm but the image is distorted and slowly blacks out over time. I've tried using external and internal sync but notging works. The scart connection seems a bit tight on one side lime the lead won't fit all the way in on that side but its in a good bit. I am attaching photos. Thanks for the help in advance!tmp_13224-IMG_20151110_173540773959056.jpg
 

SudoShinji

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So after forcing the scart in the picture became much more clear but everytine the game returns to the neo geo screen it goes fuzzy and the picture still doesn't look good.tmp_13224-IMG_20151110_175200-89645615.jpg
 

skate323k137

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What PVM model? 20M2MDU maybe?

Have you tested it with other sources of RGB?

Can you take a picture of the cable and how everything is hooked up?

I'm guessing either A, there's not enough resistance on the RGB lines, or B your video phase in the service menu is set so far to one side that it's having trouble syncing.
 

SudoShinji

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Yes that's my model. Weird thing is rgb b won't work with the same settings as rgb a at all and even when its half working the contrast and color won't adjust no matter how much I tweak.tmp_13224-IMG_20151110_181742-1923430251.jpgtmp_13224-IMG_20151110_181653-465250041.jpgtmp_13224-IMG_20151110_1816021380822483.jpgtmp_13224-IMG_20151110_1816021380822483.jpg
 

skate323k137

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OK, so, it really should be ext sync. Hard to tell from the pics but I think you have ext sync hooked up. make sure both inputs are set for RGB / Ext Sync in the normal PVM menu.

Check here and DL your manual: http://www.neo-geo.com/forums/showthread.php?248672-PVM-Service-Manuals-20M2MDU-and-others

You will need Section 3 - Set Up Adjustments starting on page 19 of the PDF. This explains how to access the service menu, and default settings and setting ranges for most common adjustments. Basically you need service mode I. Pretty much you hit menu, and then enter+degaus, but I still recommend you read the directions carefully. Once you're in the service menu find the adjustments for NOR 60 DEF : H FREQUENCY and VIDEO PHASE. If in doubt set them to the 'std' value (standard) in the menu first, and then adjust to center the picture. If one of those two is too far off it will cause the distortion up top that you are seeing.

If that does not get you going, bust out a multimeter and set it to ohms. Probe the resistors by the scart socket and check their value. If they are under 220 ohm I would recommend replacing them with 220 ohm resistors; that value tends to work for me with 20M2MDU's with all my superguns and JAMMA boards.
 
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SudoShinji

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I use ext sync for Sega which I just hooked up and is working perfectly for reference tmp_13224-IMG_20151110_183524-490846725.jpg
 

SudoShinji

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Thanks so much for the help man! So I have a cleartmp_13224-IMG_20151110_1846012060588960.jpg picture with ext sync now. It still won't really djust according yo chroma and contrast changes but its playable noe at least.
 

skate323k137

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Chroma I believe only affects the s-video or composite, I don't think it affects RGB inputs. Anyway, glad it got you going! be sure to press degauss twice before exiting the service menu to save the settings. While you're in there you can fix the picture size and positioning too.

Cheers.
 

SudoShinji

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20240215_213609.jpg
Gonna necro my old thread here to see if anyone has any ideas on my current issue. Using ext sync cart from the pvm and a regular scart from a vogatek mkiv, can hear the music and sounds and see glimpses of my beautiful turf masters in the background but cannot get sync to work. Both supergun and mvs board were sat up for a while (shamefully) and the snes right beside it works fine. Open to any ideas.
 

SudoShinji

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Well tried both mvs boards and both have the same issue so I guess it's likely the super gun but it's weird I can see the game in the background a bit so maybe the sync pin?
 
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