Gar managed to find a Williams Gorgar in non-working condition. I had a pretty good idea of what needed to be done inside the backbox, I wasn’t really aware of the magnitude of the rabbit hole I would be going down however.
let’s start with the elephant in the room: the AA batteries leaked in the very bad way with white stuff, green stuff, and blue stuff. (effectively every variety I’ve seen on a lot of Williams video game MPUs over the years, but together!) it managed to outgas straight downwards, in ways that appeared progressively worse the more I looked at it. here’s some pictures from before surgery…
the AA battery holder.
the switch matrix column drive 7406s.
the lamp column drives & blanking chips, drive transistors, and very heat damaged 27 ohm resistors.
the metallic, furry, multi-colored madness coating the legs of those chips is the outgassing from the batteries, which will spread into the base of the chip and damage the TTL inside. I wound up removing all the affected chips, the lamp column drive transistors and resistors.
surprisingly on the MPU itself, where the batteries were located, only the 7402 chip directly above the battery holder was wrecked.
so here’s how I deal with this…
when the alkaline gets into the traces it can dissolve them. I had to create a couple wire stitches. it’s not elegant looking but functionality over aesthetics.
an attempt was made to replace the 40-pin interconnect header pins at some point. albeit they’re obviously the wrong height. (you want the longer pins here). it’s not very evident from the angle of the picture but the factory pins were skinny and round and prone to bending while the replacements are square shaped and much more solid.
you can see where I took the header pins out where the leakage got into the pads underneath. also I socketed the 5101 CMOS; the board would receive an NVRAM later.
here’s the proper replacement header pins.
the MPU was quite simple to work on compared to what would follow. in all I replaced all the header pins around, replaced the 6808 CPU socket, 5101 CMOS socket, the IC14 Game ROM socket (it came with the 3 PROMs, it now has a 2716 Game ROM), 40-pin interconnect, and after all the sanding and cleanup it got washed in the sink.
next up is the Driver Board…
the 7406 switch matrix column drive chips. I lost some traces, so this battery thing must have been sitting for a long time.
7408 lamp column drives & blanking chips. I wound replacing these both and the lamp row 7406 just for the sake of completion. (these will come into play again later)
I had to strip all the bits out.
the first iteration of the reworked driver board. if you look close you may notice a mistake. this was just replacement of damaged chips, the TIP42 transistors and 27 ohm resistors sourced from an extra Hyperball Control Board.
since I’d used up the last of the header pins and interconnect plugs from Firepower and Blackout I had to wait until we got the next batch of parts from Mouser.
now comes the power supply.
we have several of these sitting on the pinball parts shelf, but this was the first time encountering one in a game. this is the vintage power supply you’d find in a Williams System 6 game such as Gorgar. the capacitors totally look their 45+ year old age and I would soon discover they acted it as well.
after all my work on rehabbing the MPU, it powered up just fine when I tested it on the bench but didn’t work in the game. all these solid state pinball games of the era use +12V for the reset circuit — without good 12 volt supply it won’t boot. seen below is me testing that voltage, at 8.15V it wasn’t enough. the power supply would need a cap kit.
this was our ringer power supply we took to MGC in case the Rottendog one in Firepower had issues. I had to go on a scavenger hunt to find it since it was in one of the tubs located in a random place. but this was what I needed to get the game to boot up.
when you see this on the score displays it’s a good sign. that 1496 number is apparently the version of the game software so you know it’s running Gorgar code.
our journey surveying the wreckage isn’t over yet though…
if you could believe, even the sound board was on the fritz. there’s a tantalum capacitor that can short out to the voltage regulator that produces +5V. when this happens you have no juice for the logic components.
the component tester says that the capacitor thinks he’s a diode. which I thought was kind of amusing cause that’s how it tested with the meter, the leads had to be a certain way just like testing a diode.
I don’t have 1 uf 25V tantalum capacitors, my fix on the video game sound boards has always been to install an electrolytic in its place. upon doing this though Gorgar speaks!
here’s a visual aid of what the playfield looked like before Gar did any waxing.
since a lot more happened since the first pass here, I’m putting the rest of the material in a part 2.