The screen my machine came with was busted, and the replacement was the wrong part. I wasn't smart enough to see that when I purchased the machine (but I am now). In any case, I've spent about a month of time (waiting on parts and other things) trying to get my screen working reliably, and with much support from the folks over at ColorDMD, I've finally been able to get it working:
The main problem was my ROMs. Maverick has 5 ROMs in it, 1 for the CPU, 2 for the display, and 2 more for the sound. In my case, my CPU and display ROMs were an older version, and the new color display wasn't programmed to support the older pinball software. After much back and forth with the folks at ColorDMD, we decided it was likely that upgrading the ROMs would fix the problem.
27C256
At the junction when you decide you need to upgrade your ROMs, you have 2 choices. You can either order some, or (if you're a nerd like me), you can burn the new code into the old ROMs after erasing them.
ROM chips from this era typically had a little window to erase them with UV light. (And the ROMs that weren't sold as erasable typically were UV erasable anyway – they just didn't have the little window in them):
While I don't have a ROM eraser anymore, any strong UV source could erase a ROM. In my case, I was just going to use a UV nail setter to erase them:
But, as I put the nail lamp into my cart on Amazon, I started to have second thoughts. What if the ROM images I found online didn't work? So, I researched buying new chips, and burning them. But, these old ROM chips are kind of expensive now-a-days. You can get them for about 8$ a piece from a reputable dealer (Jameco, Digikey, etc.), but I can order them pre-burnt for about 8$ a piece from a pinball ROM shop on pinside.
So, deciding that it was most prudent to just order new ROMs, and keep the old ones incase something went sideways, I bought some ROMs:
This afternoon, the ROMs got here, and I yanked out the old ones, and put in the new ones. And, now it seems like I have a reliable screen! I'm very excited. I can get back to the machine and debugging all the mechanical bits.
One Other Aside
It's been a couple of weeks since I posted, largely because I was waiting on the ROMs, and I had some personal stuff come up in my life preventing me from really working on my hobbies at all. While I'm disappointed in my velocity, I am not disappointed in how things are coming out. I am learning a lot about refurbing pinball machines, and I think this machine will be end up as a reliable workhorse when I'm done.
I hope my update frequency will increase as most of my personal stuff is clearing up, and I now have a working screen to help diagnose the rest of the problems.
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