Topic: Psychic5 video distortion. Input needed! };-S  (Read 2322 times)

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Offline Elgen

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Psychic5 video distortion. Input needed! };-S
« on: March 06, 2013, 07:10:03 PM »
Hey Mates

I currently have a bootleg Psychic5 on the table. I've made some repairs in the controls/input section and made a JAMMA-adaptor, and it now plays perfectly.

HOWEVER, there are some small, tho rather annoying, distortions in the upper part of the screen.
It looks like small white stripes about ½-1cm long (in the direction of the scanlines) and 1pixel wide. They only apear during gameplay (or gameplay-part of the attract-mode), and not all the time.

I've to take 2 stills of it with my iPhone

I've also shot a small video of it

The board is 2 PCBs with ribbons, and video is generated on the secondary PCB. The fault is definitly on the second board, cause I've got another Psychic5 (maby original?) with identical secondary PCB. And if I swap the PCBs, the error swaps as well.

I've traced the R/G/B and SYNC lines back på this section on the secondary board; actually they go directly to some of the resistors

Another piece of info is, that this game can flip the screen via dip switch, and when I do so, the interference still appear in the same physical place on the screen (top); it doesn't flip along with the picture.

I'm pretty sure, that this interference is induced into the video signal during the very last steps of the video generation, as it looks like affects both back grounds and sprites, but that is just my feeling...could be wrong.

This is really starting to annoy me, so any input would be nice.

Also, should anyone have a scan of the schematics for the game, I would be very glad to get a copy; haven't been able to find it via googling.