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Author Topic: Boulder Dash  (Read 18486 times)
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« on: November 22, 2005, 09:07:48 PM »

Company : Exidy
Cabinet : Max-a-flex
Monitor : 19" horizontal color raster

I picked up this game non-working from eBay. I won the auction for it in late July 2002. The cabinet was in San Jose. I asked my good buddy Lance Lewis if he could pick the game up for me and hold it until the 2002 CA Extreme show in September in San Jose. Being the excellent human he is, Lance agreed to pick up the game and stash it in his storage unit until I could get there. Thanks Lance!! I figured I'd head up there a day early and try to get the game working and take it to the show.

This game is in an Exidy Max-A-Flex cabinet, which is basically an arcade cabinet with an Atari 600XL computer inside. There is additional hardware that controls the length of time that you may play the game. Each time you insert a quarter, an amount of time determined by dip switch settings on the controller board is added. While the timer is running, all controls are active and you can control the game via Start, Select, Option, an 8-way joystick and one button. When the timer gets down to 10 seconds of play remaining, the control board starts beeping a progressively higher pitched beep and flashing the"insert coin" and "extend play" lights. When the timer gets to zero, the controls become non-functional, but the game does not reset, so you could add more coins and continue playing.

On the Friday before the show, my friend George Weising and I rented a truck and drove to SJ. When I arrived at Lance's house, we went to his storage unit and got the game and brought it back to his driveway. Lance then made me drink some beers even though he and I both know it makes it harder to fix stuff. I went over the wiring and found a couple danglers and a couple plugged in the wrong spot. When it all looked right, I gave it the juice and stood back a few feet. An image appeared on the monitor but it was just some red diagonal lines. Okay, it's non-working as advertised. The first thing I did was test the power supply to the computer. Where it said there should be +5v, I was reading +7.5v. There's a problem. Lance happened to have an extra switching power supply he let me borrow, so I snipped the wires off the old supply and stuck 'em on the new. Gave it the juice again with no change except there was +5v where there was supposed to be. I took a close look at the wiring and found that there were two black RCA cables coming out of the Atari 600XL and one wasn't plugged in. I figured these must be audio and video, but they weren't labeled and they were both identical. I tried swapping them, with no change. I asked Lance if he had a small TV set. He did, but it didn't have composite inputs. I asked if he might have an old RF converter. He did. (Lance has everything). I hooked it up to the TV and plugged one of the black RCA cables from the computer into it. Put both it and the computer on channel 3 and gave it juice. The screen full of static on the TV changed to a different type of static, but didn't give a picture. I decided to crack the case on the computer to see if I could tell what the two black RCA cables did. Once open, it was clear which was which. One was audio and one was composite video. Won't work with an RF converter like I was trying to use. I asked Lance if he had a VCR I could hook up to the arcade cabinet to see if it produced an image on the arcade monitor if I hooked it up to the composite->RGB converter. Of course, Lance had one, so I hooked it up and applied the juice... same red diagonal lines.At that point my friend George asked if the cable from the converter to the monitor was plugged in correctly. It looked correct, but to be sure, I traced the ground wire from the converter to the monitor. Crap. It was backwards. I plugged it in the right way and powered up and there's the image of the VCR on the screen. Time for another beer. I unhooked the VCR, put it and the TV back in Lance's house and tidied up the area from all the crap I had strewn about by this time. Then I put the computer back together, hooked it all up the right way around, and gave it the juice. This time we got an image. Yay! It was a solid blue screen with a little square cursor in the upper left corner. Nothing else. Boo. If I added coins, the computer would reset and a buzzing sound was made and a lighter blue square filled most of the screen. Bleh. I tried pulling out the cartridge and it behaved exactly the same way. Hmmm. Maybe dirty contacts on the cart's edge connector, or the contacts in the computer's cartridge slot. I asked Lance if he had any sand paper, and he did. At that point I should have asked Lance if he had a cute, single sister who liked boys who like games, but I had been drinking beers and my brain wasn't working how it should, so it didn't occur to me. And besides, I'm married. We cleaned the cartridge over and over and tried wiggling it around while powered up and all the standard cartridge tricks, but the best we could do was get some random numbers and garbage characters to show up. It was getting into the evening and I was itching to see how the show setup was coming along, so I cleaned everything up, bolted everything down and dragged George away from Lance's Discs of Tron to get the Boulder Dash to the show. Al Kossow was supposed to show up at some point with some of his Max-A-Flex carts and, with luck, a bad cart would be my only problem. We got to the show but didn't see any sign of Al and all the folks that knew him said his phone wasn't working, so we fiddled with the game some more to no avail and gave up for the night and helped other folks set up their games.

The next day we got to the show early and fiddled some more, but no luck. Still no sign of Al. The show started and we wandered around in awe playing all the cool stuff. I ran into Bill Esquival and told him about my game and he said he had some Atari 800 carts at home and would bring them by later (he lives in San Jose). Around 7pm I felt a tap on the shoulder and it was Bill with a handfull of carts including a Boulder Dash. Way to go, Bill!! I ran over to the game and plugged in the new cart and went around the front to be greeted with the Boulder Dash title screen. Wa-hoo! The colors were very bad and very bright. I had George hold the monitor plexi in front of the game so I could see a reflection of the monitor from the back and started adjusting knobs. It seemed like every knob on the monitor and converter board had been turned all the way in one direction or the other. A few minutes of fiddling got a decent picture with wierd colors. A few more minutes of fiddling got a decent picture with decent colors. Good enough! I went around front, put the plexi back on, coined it up and played my first game of Boulder Dash at around 7:30 pm, Saturday, right on the show floor.

The game worked fine the rest of the night and through Sunday until it was time to turn it off and head back home. Bill said I could borrow his cartridge to try dumping it to fix mine. Bill's awesome. After I got home and settled in, I opened my cart and desoldered the masked ROMs inside and read them in my EPROM reader. One was blank. Ah, ha. I didn't want to open Bill's cart because they're quite rare and the case is glued shut. I decided to build an adapter to read the whole thing as an EPROM. I looked up the pinouts for an Atari 800 cart on the internet, found them and made an adapter. I dumped the contents of Bill's cart and tried it in an emulator and it worked great. Yay, good dump. Then I modified my bad cart to take a pair of 2764 EPROMs and burned Bill's data onto my cart. Plugged it into the game and it worked like a charm. Horray!

There are three other games that were made for the Max-A-Flex system. Bristles, Flip and Flop and Astro Chase. My cabinet came with marquees for all the games, but only a cart for Boulder Dash. Al Kossow was in the area and stopped by and loaned me his Astro Chase and Bristles carts to dump. Then, a little while later, my good Max-a-Luck streak held and someone sent me a working dump of Flip and Flop! Yay! I've got 'em all. I burned each one to EPROMs and tested them on my hacked cart and they all work great.

Now I just need some other junky carts to convert to these games permanently... or should I make a multi-cart... hmmmm... yeah... that's it! I'll make a multi-game and call it the Multi-Flex. I'll write a little front-end program to choose between the four games at boot, then modify the 68705 code to come up with a way to reset back to the front end, perhaps with a shift-combo of the option and select buttons. Then I'll design a custom marquee with images of all four games on it... it'll rock! Of course, I won't do anything permanent to the cabinet so it could all be changed back if wanted. Oh, well. Someday, maybe after I retire, I'll get around to really doing it.

I scanned the manual in high-res, but it's too big to make available for download here. Here is a low-res version. If you need a high-res version to better read the schematics, drop me an email.

In early 2005, I got an email from someone at First Star Software looking for dumps of the Max-a-flex games so they could rip the music out of them for a project they were working on. (They must have google'd me and found that I had the carts for my cabinet). This was long before the games were supported by MAME, so the dumps weren't readily available. I told 'em I'd be happy to supply them with dumps and I had a favor to ask. A friend of mine, Ken Chaney, has a Max-a-flex cabinet with a Boulder Dash marquee but he is missing the cartridge. So I asked them if I could have a single-use license giving me permission to copy my Boulder Dash cartridge and give it to Ken so he'd have a legal copy of the game. They agreed and sent us an agreement to sign! Super neat. Now Ken has a legit Boulder Dash and the papers to prove it. Smiley

I can't think of many things cooler than having a license to make one copy of a classic game cartridge form the company who made it. Here's the unsigned version for your viewing pleasure (don't want our siggys floating around the net).

Additional photos

Top - composite to RGB converter. Middle - Atari 600XL.
Bottom right - replacement switching power supply.

The additional control board. Has a 68705 MCU, audio amp, timer, etc.

My hack-job Atari 800 cartridge reader.

My original cart modified to take a pair of 2764's.

The other stuff I got with the cabinet.

Al let me borrow his Astro Chase...

...and Bristles carts to dump.

Brian Clark sent a picture of his Flip and Flop cart.

He was lucky and got all four carts with his cabinet!

You can email me at
« Last Edit: July 30, 2007, 09:43:25 AM by tim » Logged
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