orc123
New member
Vigilante on TV - constant picture roll-up problem - maybe the vsync? please help
Hi,
please, do you have some experience with picture rolling up (or say jumping) problem when running a PCB on a TV?
I connected my Vigilante JAMMA PCB to the older 72" PAL CRT TV trough the RGB SCART connector.
I used 220 ohm resistors on RGB lines and the colors are almost perfect (maybe even a bit too dark - the resistors are probably not at all necessary in this case).
First I tried to put 1Kohm resistor on the SYNC line.
The only problem is, that the picture is constantly rolling-up approx. 2 times a second. I can see, that the picture is perfect in other ways when I use digital picture capture/hold function on the TV.
I also tried to connect some other resistors to the SYNC line (220,330 ohm,5 and 10Kohm,etc.) and it seems not to help. I see basicly no difference in the roll-up speed when I am changing the resistors, but just in the case of high resistors sizes (10 Kohm and more) it gets even badder and later the SYNC is lost totally.
I only suggest - please, is the "rolling-up" picture on TV probably a SYNC problem or something else? Can a variable resistor (POT) to ground on the SYNC line help in this situation or maybe should I also try to remove the resistors from RGB lines - could this help?
I also got into the TV service menu, but found only setting for picture size and geometry, not something like the vsync.
Please, is this probably a bug or feature of the PCB?
I added pictures (frozen by TVs picture hold function), how it looks.
Is there a way to fix this in some way or have I to use another TV or monitor for this?
Thanks very much.
Hi,
please, do you have some experience with picture rolling up (or say jumping) problem when running a PCB on a TV?
I connected my Vigilante JAMMA PCB to the older 72" PAL CRT TV trough the RGB SCART connector.
I used 220 ohm resistors on RGB lines and the colors are almost perfect (maybe even a bit too dark - the resistors are probably not at all necessary in this case).
First I tried to put 1Kohm resistor on the SYNC line.
The only problem is, that the picture is constantly rolling-up approx. 2 times a second. I can see, that the picture is perfect in other ways when I use digital picture capture/hold function on the TV.
I also tried to connect some other resistors to the SYNC line (220,330 ohm,5 and 10Kohm,etc.) and it seems not to help. I see basicly no difference in the roll-up speed when I am changing the resistors, but just in the case of high resistors sizes (10 Kohm and more) it gets even badder and later the SYNC is lost totally.
I only suggest - please, is the "rolling-up" picture on TV probably a SYNC problem or something else? Can a variable resistor (POT) to ground on the SYNC line help in this situation or maybe should I also try to remove the resistors from RGB lines - could this help?
I also got into the TV service menu, but found only setting for picture size and geometry, not something like the vsync.
Please, is this probably a bug or feature of the PCB?
I added pictures (frozen by TVs picture hold function), how it looks.
Is there a way to fix this in some way or have I to use another TV or monitor for this?
Thanks very much.
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