Bubble Bobble, HELP!

PCB problems and fixes
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Unite2k
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Bubble Bobble, HELP!

Post by Unite2k »

Good afternoon guys,

I recently got an original Bubble Bobble PCB with the jamma harness. Unfortunately its not working, I'm getting a dull Black & white image but the sound works perfectly. See the photos of how its connected in my cabinet and the screen images. I've used 20+ pcbs on this cab without a problem, inc. Tetris, Rainbow Islands, New Zealand Story, Shinobi (with adapter), Track & Field (with adapter). Any ideas on this one?

Cheers,
Cedric
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Re: Bubble Bobble, HELP!

Post by cools »

Step 1, grab multimeter and check voltages under load.
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Devil Soundwave
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Re: Bubble Bobble, HELP!

Post by Devil Soundwave »

To add some more info - this was mine.

I have never seen this white screen issue before, and it appears to be hooked up ok.

It would seem Cedric isn't in the habit of checking voltages when adding new boards but hopefully this is not the issue. :?

I have asked Cedric to take some further pics which he will get for us tomorrow.

Luckily we both live in London so unless you guys can assist I will go round next week to troubleshoot.

Any help and suggestions would be greatly appreciated!
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Chi
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Re: Bubble Bobble, HELP!

Post by Chi »

Why is there no video ground wire on your JAMMA harness?
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Re: Bubble Bobble, HELP!

Post by kernow »

It does look like its not synching, the video ground might explain that no?

Well, you can see the level layout on that pic clearly, so maybe not synching, but something else. Bet theres nothing wrong with it and its the lack of video ground as Chi so observedly pointed out.
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Re: Bubble Bobble, HELP!

Post by Devil Soundwave »

That'd be pin 14 on your machine harness btw Cedric.
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Re: Bubble Bobble, HELP!

Post by Chi »

kernow wrote:It does look like its not synching, the video ground might explain that no?
FWIW, I can see a synced picture underneath all the grey (it looks like sillouhettes, but is synced). My money (all 1p of it) is on the lack of video ground on the harness though, I guess BB relies on it?

EDIT: Kern edited his post whilst I was posting this, the bugger :awe:
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Re: Bubble Bobble, HELP!

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Re: Bubble Bobble, HELP!

Post by trmatthe »

Well the sound CPU is running and the game code is running otherwise you wouldn't have those images behind the whiteness so the board is working.

The whiteness is caused by your monitor not having a ground reference so it doesn't have any idea of the intensity of the video signal, which in English means add a wire on your JAMMA connector from either of the end pins (pins 1/2 or pin 27/28) to pin 14 on the top side of the connector aka the "parts side". Do that and magically you'll have a gorgeous picture. Doesn't have to be a particularly chunky wire as it's not going to carry any significant current.

And once you've done that I'd then plug the board back in and measure the voltage on one of the 74 series logic chips on the top or bottom board. You want to be reading about 5.0X on the top board away from the edge connector. Refer to the wiki at http://wiki.arcadeotaku.com/w/Measuring_Voltages" (and my assome pic :awe:) for tips on how to measure the voltage.

And the play away!

cheers
tim

ps Am willing to bet this is going into a Candy. If not then somebody very naughty has wired this machine.
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Re: Bubble Bobble, HELP!

Post by trmatthe »

Also, wiring in the video ground means that you'll never encounter this on any other boards in the future. You must have been lucky with your adaptors in the past that bridged video ground to power ground.
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Re: Bubble Bobble, HELP!

Post by cools »

trmatthe wrote:ps Am willing to bet this is going into a Candy. If not then somebody very naughty has wired this machine.
Sure looks like a wooden one in the photo.
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Re: Bubble Bobble, HELP!

Post by trmatthe »

cools wrote:Sure looks like a wooden one in the photo.
Tru dat. I was overwhelmed by the abundance of wiring in there and was trying to figure out who had transplanted what. The edge connector looks way too good condition to be original, and the heatshrink suggest a pro job so I was wondering why there was a floating video ground. Which then led to me wondering if vid gnd was wired further up the line nearer to the monitor which would invalidate the suggested fix, but then the fault is very similar to what you'd get without a video ground so I got all confused.

I was wondering where +12V was fed from but given that the sound is working I guess the bit of blue cable near the top end of the connector is soldered to the solder side pin for +12 and the bridge between parts and solder sides for that pin is obscured by the camera flash.

ps I reckon somebody shooped the woodie bits in; I can see the pixels :spam: .
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Re: Bubble Bobble, HELP!

Post by Devil Soundwave »

Thanks boys, knew I could rely on Arcade Otaku.
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