In May 2016, I purchased a Zero Point machine along with another 9 games for $400 in my Barn Find.



All the machines were dirty but this one had to be one of the top three nastiest cabinets:



Another shot of filth:



Not looking any better:



The cobwebs were incredible. They were everywhere:



The inside wasn't any better:



OMG!



WOW! This was a new one. While I was cleaning out the cab, I told my wife "Hey, there is a skull in here!". She thought I was saying there was a drawing of a skull inside the machine but I was talking about an actual dead body in an arcade cabinet. This was kind of strange because when we picked the game up the back door and coin doors were secured. I have no idea how this creature (my guess is a possum) got into the machine or what killed it:



Ah, that is a little better. After about four hours of cleaning I can actually put my hand inside without fearing for my life.



I went through my usual sequence of checking the power cord, checking the power supply, checking the isolation transformer, checking the monitor and then finally powering up the pcb. I was happy to see that everything powered up just fine. The monitor looked like hell but at least it worked:



Once I saw that everything worked (not perfectly, but it fired up) it I figured I would start cleaning up the control panel. As I dug through the layers of plexyglass, control panel overlay, etc I found something interesting on the bottom layer. This cab was originally a Pit-Fighter:



The last step in cleaning an arcade machine is cleaning the glass and monitor. This is the last step because you normally have to take off the control panel to do it. I could see a ton of bugs behind the glass:



Holy Shit! I've had my hands in the "clean" cabinet for hours and this monster pops out. If this thing would have ran up my arm I would probably had a heart attack. I was cleaning the machine at night while my wife was sleeping. She would have found me on the floor of the shop, dead with a spider eating my face or something:



I politely asked the spider to exit the cabinet and I threw a Benjamin down beside him for some reference. I know you are saying "Yeah, that spider it not very big" but take a $100 out of your wallet and compare it to my picture. Then add an inch to compensate if his legs were fully extented. Now I understand how the possum got in there. This tarantula grabbed him, unlocked the door and pulled him in:



The pcb was stuck in test mode and the monitor looked like hell. It was time to order a cap kit and see if that helped:



Hmmm, this was now getting interesting. The cap kit did not help at all but when I swapped the RED and GREEN wires going to the video feed header on the monitor chassis I now only had RED:



It took me a little while to figure out the problem. I ended up swapping out IC1, the neckboard transistors, and a few other things. As I was just about to give up I looked back at an old picture the one above and it became crystal clear. I was only feeding it a GREEN signal. It ended up being just some stressed wires at the jamma harness. A fairly easy fix but it looks like this conversion from Pit-Fighter left a little to be desired when it came to wiring. It seems like every wire in the cabinet was stretched to its limit. I don't know if I will work on this at some point or not. Anyway, when I finally got the monitor working it was easy to see that there was a problem with the sprites in the game. All the background graphics looked fine but the sprites were a jumbled mess. I could not find my PLCC chip extractor so I could pull the roms out and clean them so I ordered one off Ebay and put the graphics problem on the back burner:



The most important part of a light gun game (other than getting the PCB working) was the guns. They were as nasty as the rest of the cabinet and from the look of the rusty hardware I doubted I would even be able to get them open:



It seems as though some dirt dobbers made their home in the red gun:



Spiders made their home in the blue gun (hard to see but there are three of them to the left of the trigger):



After a few hours of cleaning I had the guns in working order and looking good. I put the control panel back together and took a look. WOW, this is light years ahead of where I started:



I know you are forgetting what it looked like. Here is a picture:



After getting the guns working and cleaning the control panel, I went back to working on the graphics. The first thing I wanted to do is clean the dirty pcb:



This was the first pcb I have cleaned and I wasn't sure what I would do. I used LA Awesome from Dollar Tree for my soap and scrubbed it in with a tooth brush. After rinsing it off I put it in a pre-heated oven to dry. I am happy with the results:



After cleaning the pcb I started looking for the cause of the bad sprites. I figured I had a bad 6116 RAM chip so that is where I focused my attention:



I purchased a second Zero Point pcb so I would have some spare parts. I pulled the eight 6116 chips off each board and replaced them with 24 pin sockets so I could swap them in and out easier:



I marked the original 6116 chips with numbers and the replacement chips with letters. I tried my best to just swap them in and out and look at the sprites but that just didn't work:



In the end I purchased a NeoLoch RAM Tester and used that to determine which was bad and which was good. I found two bad 6116 chips on the original board and three on the replacement board. It was easy to test them and I should have bought the tester and did it that way from the beginning:



Here is what the graphics did look like:



And here is how they look now. Yes, it is supposed to say "Zero Point" in the picture above: