Sunday, 14 August 2016

Fixing a Midway Rampage Arcade PCB (MCR Monoboard 1986)


I thought i'd start a new thread on another hardware project i have started recently. I'm really enjoying learning about old arcade pcb designs and how they work etc after getting my Nintendo Donkey Kong 4 stack up and running earlier on this year/last year as its something different to pinball pcbs which i work on all the time!. I have another nintendo pcb coming soon which i'll be diving into aswell on another thread - Donkey Kong Jr pcb, but this thread is about my latest purchase of a Midway Monoboard :)

So i was going through some of the old 8-bit games having a look at some of my old favourites and who made them etc. This was started by the discs of tron speech board project i did recently for someone. I found myself looking up all the old Midway (Bally) arcade games that came out at a similar time to Tron and the few years after etc. Tapper was one that i really loved and still do and another was Rampage.

I started researching about the MCR boards sets and the monoboard version for Rampage. This lead me to search for some on eBay which i ended up finding an 'as is' untested and presumed non working 'Sarge' pcb.

I decided to see if i could get this board up and running somehow and convert it to a Rampage game. As what to do with the cabinet side of things once i get the pcb to work is something else to think about and i may build a new cabinet solely for running original pcbs in etc Ideas welcome here :)

So whilst waiting for the PCB to arrive from the USA i burnt a new set of roms in anticipation.

The board arrived this week just gone and i had a check over it. There were a couple of missing chips, some broken caps and a rusty cpu chip, but other than being pretty dusty it all looked pretty good.

Changed the CPU chip and replaced the 3 large power caps. Changed over the full ROM set and reseated all socketed chips. Made some test cables, 1 power cable and 1 video cable.

Plugged it all together. Now, currently i don't have a spare CGA monitors so i'm using a gonbes arcade vga to cga convertor card and an LCD for testing. This may or may not be a good idea but i wanted to see what i good get on screen if anything :)

At first power on i didn't get anything other than a pure green screen, then after a little bit of messing with power cabling to the gonbes board, checking a few signals to the cpu with my trusty basic logic probe and pressing the reset button on the MCR board a few times, I got a few glimpses of the following:

Pretty damn happy to see this even though there is more work to do with the sync etc. These images flash up on screen then go back to 'no signal' so i'm wondering if the gonbes card is no use really here and i need to get something else setup for the picture. Anyway that's where i'm at with it so far. Let me know what you think :)

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