Rockola experts: Nibbler to Jamma

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Picked up a Nibbler board that was stated as "working"

I have a cabinet that is wired for Jamma.
--using Nibbler to Jamma adapter from Mike's arcade
--using a CGA 2VGA card
--Dell 19inch LCD
--switching PS for typical 12v, +5, and -5.
--works fine for real pcbs of Moon Patrol and Tutankham with Bob Roberts Jamma adapters so I know it's a good setup.

When turned on, the monitor says "No signal" for awhile, then I can hear some high frequency buzzing, then the nibbler screen appears for a second/grainy, it rolls vertically once then disappears. rinse and repeat.

I've tried various cga/vga card resolutions, same behavior.

Anyone ever tried a Rockola to Jamma setup or have some hints to pursue. Is there something unique about the video output for Rockola setups?

I have a real CGA monitor in an arkanoid cab. I suppose I could rig up the jamma harness to temporarily use that monitor as a test. if I have to, but I'd rather not.

Thanks in advance.
 
They had an LCD on the Nibbler at Galloping Ghost for awhile, but I don't know what type it was (if it was one that accepted CGA, or if he had a CGA-VGA adapter card in it). Nibbler should work ok with a PC switcher, I had a board I was borrowing for awhile and used one to power it. It only needs +5 and +12. That being said, Nibbler is kinda funny with monitors. I'd get curl on the side on my G07 where no other games would do it. The one at Galloping Ghost also curls a tiny bit with a regular CGA monitor in it.
 
I hand built a Nibbler to Jamma adaptor with no special parts and it worked fine on a K7000. I don't think there is anything special about the Nibbler boardset...
 
Fred, didn't you put the jamma harness on Tim's Nibbler?
I may have to run the board up to Tim's and try it in his machine.
Getting something in the mail, it's really hard to know if the board is good.
I reseated the ribbon cables.

Are the schematics online anywhere?

That curl thing at the top is the sync circuit. I have a joust monitor that curls now after the circuit was changed per the bob roberts instructions, which was supposed to stop that curl stuff with newer pcbs.

IMG_20120106_171326.jpg


IMG_20120106_171346.jpg
 
Yeah, he thought there was something wrong with the harness since he was having problems with it not coming up, and this was just before the Big Bang. There wasn't really much time to order parts, and I had an extra JAMMA connector, and since he already had a Nibbler-JAMMA adapter, he figured it'd be good to redo the connector as JAMMA (then he could use other JAMMA boards too). It didn't fix the problem though, and it turned out it was the power supply instead (which I think Star Worlds rebuilt or replaced, not really sure what they did with it). I ended up borrowing a spare board, and wired up his old connector to a switcher and used it on one of my cabs for awhile before sending the board back to him ;)
 
Next week or so I'm going to try the board in Tim's machine.
The way this appears to me, that video is off, then it comes on for a second and rolls, makes me very suspicious of the video output from the board itself.

I got it from Quarterarcade so I'm sure he'll replace it if it's defective.
 
tried the board in a nibbler machine with jamma adapter.
Works properly. whew.

so the sync signals off the nibbler boards must be slightly out of the range that a cga/vga converter card can handle.
going to put a small cga monitor in the cab and roll with it.

I did learn that the Mike's arcade Nibbler adapter is missing the wiring to start a 2player game. Gotta add the wiring on the adapter itself.

also learned that this board is v9, where the dots get regenerated when you die on a maze. they marathon v6 because the dots don't regenerate so you can point press the timer when dying.

Thanks for the help everyone!
 
The one at Galloping Ghost (and the board I borrowed from Tim awhile back) were both version 9. The regenerating croutons don't actually start until wave 32 (according to Tim). I've gotten as high as 27 or 28 on GG's machine and haven't seen them regenerate yet. I think I'd be screwed if I can get that high though...there's one board I haven't figured out a pattern for yet without dying.
 
I learned this game from tom asaki at the same time Tim did. it'll be interesting to see if the patterns come back to me. probably never played it over 14million. nowadays i get around 100k when i try it.

getting closer to having the cga monitor ready for the cabinet. got the cap kit in the g07, have the power brick made. have to remember where to connect the video into the jamma harness for the sync....
 
got this up and running with a 13inch monitor with go7 fbo chassis. works great.

i presume if i had an oscilloscope i'd find that the video signal is just outside the range of what that cga/vga converter card can manage.
odd but good to know that some pcbs don't work for the converter card.
 
holy cow, that dot regeneration thing is a pain.
i heard athometech can get copies of the v6 software to avoid this, think i'm going to do that.

I played half a dozen games today to get a feel for it and mess with the wico stick.
545k, lost 3 men quickly on wave 33.

the patterns are coming back a bit if i don't think about it. can't remember a pattern for 7, though.
 
We've had this issue with cga/vga adapters in Missile Command. I still havnt found one that works.

I'll look into the ROMs needed to go from 9 to 6 and let you know what I can do about getting you a set of V6 ROMs.

-Ken
 
Thank you Thank you!

ps-got a reply from Mike's arcade that all future Nibbler adapters will have the 2player wiring installed.
 
well i see v9 isn't impossible, it just forces one to be precise on the patterns.
rolled the waves and play to 6.5m today.
still can't remember or figure out a good pattern for wave 30/94.
 
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