The SpaceInvaders:MonitorRestore Project

3/17/07 - Took Some Pics / Ripped Stuff Apart

My Space Invaders is feeling a bit under the weather. When I got it, it barely worked for more than 5 minutes. When it was working, I noticed the monitor was a bit narrow. Of course I tryed the obvious knob twiddling but without success. Turns out after some severe self-edumacation I concluded that it's a vertical deflection issue, (, maybe. I'm going with what I know.) Either a transistor is bad or a capacitor is going bad, (more likely the latter.) I decided to rip the machine apart and give a go at my first monitor repair. I figured I'm gonna' get shocked sooner or later... why wait? Besides, in the end, I'll have a nice, clean, polished up Space Invaders with a new, pretty, full screen picture.

OK... so first off, before I did anything, I took a ton of pictures of everything I was going to be fiddling with. Better safe than sorry. This turned out to be extremely helpful since the high voltage wire popped off with the diode thingy after it. I woulda' been screwed otherwise. I made sure I got plenty of shots of the PCB and the monitor neck and all the wires connecting to it.

Getting that monitor board out was a pain in the arse. The board is so damn snug to the neck of the CRT that I snapped the damn little cap thing off the end of the neck while trying to wrestle it outta' there. All well, a little crazy glue will fix that up. You see those little prongs sticking out of the end of the neck on the CRT in the left picture? Those bend REAL easy. After a bit of trial and error, I managed to contort and shimmy the damn board out of the cabinet. Whoever designed that cab was really sadistic. Anyway, the board was a mess. A lot of gunk on it. The PCB was attached to a larger mounting assembly that had its power supply and controls by connecting pins. They were in there real good and I didn't want to just start prying it off with my hands or a screwdriver. So I grabbed an old toothbrush with a soft rubber grip and pryed it in there to loosen it off the pins. Worked like a charm since the soft handle of the toothbrush was real gentle on the board, (you can see the toothbrush and a pen as leverage in the picture on the right.) It feels brittle... I mean matzo bread brittle. Once I got it off, I grabbed a can of degreaser and sprayed it down real good. I finished it off by brushing the crap off with a hogs hair brush and some QTips. After hosing it down and cleaning it up, I wondered if it was cool it clean that crap off the high voltage wire thinking it was supposed to be some sort of long lasting lubricant. Too late... I'll have to ask around. I followed all that up by cleaning up the board assembly and testing the pots and other components for failures. Everything checked out OK.

It was then time to take the monitor out. I put on a pair of biker gloves so I wouldn't get a nice jolt and kill myself while playing with that thing. I tested it with a high voltage meter probe under the high voltage cup and it read nothing, (did it discharge on its own? Beats me.) Fuck it... I grabbed the cup, squeezed it tight and it came right off. Sweet... no problem. Getting the monitor out from then on wasn't too bad other than the awkward positioning of the chassis mounts. It was filthy as well. I placed it on an old comforter sheet and cleaned it off good with the hogs hair brush. Looks brand new now, (not really but good enough.)

From there out, I started pulling everything else out and cleaning it up. Years and years of dust and grime in there. Looks like a few gallons of soda were spilled down the back and dripped on the PCB. Good stuff. Cleaned it all out, vacummed up in there and took some pics of the parts.

I called up ArcadeShop and ordered a cap kit from them, (I couldn't believe they had them. Once again, a life saver.) So now I'm sittin' on my butt updating this until it shows up. ;)

7/25/07 - Testing Components

OK, a few months ago I've gotten the cap kit from and replaced all the caps although I had to get two different caps since my monitor was a 19V1001 not the 19V1000 listed on their site.

I've finally gotten time to take the monitor out again and test each component and, lo and behold, not one but three potentiometers were bad. I suspected they were bad to begin with since adjusting them didn't change the display. All the other components were good.

All I gotta' do is find replacement pots. Click here to see a big-ass picture of the pots.

7/26/07 - Replacement Components Found!

After a little bit of investigating, I've finally found the manufacturer of those pots located here: CTS Corporation and the specific trim pots are here: Series 201X 15.08mm Trimmer Pots

Pretty bitchin'!

8/3/07 - Final Countdown!

Finally... today's the day that the components should arrive in the mail. When I got home, I was sad:

Damn, all well... they'll arrive soon enough. I wrote it off. I headed to the back and what do I see waiting for me?

Oh, yeah... it's on! I put everything aside and fired up the solderer. I placed the 1M pot and put the monitor board assembly back together. You can see in the picture below the replaced potentiometers, (blue thumbwheel).

I was very anxious at this point. What if I had done something so tragically wrong that when I power up the game it explodes and takes me with it in a fiery blast as if smiting me for its demise. Screw it... plug the damn thing in. The following depicts what happened:

Awwwwwww..... YEAAAHHHHHH!!! HIGH FIVE!!! It's Miller Time!!! It powered up the first try and I didn't even have to adjust anything. Is that friggin' awesome or what?! I played a few rounds with the biggest of shit-eating grins on my face. The Invaders are back... and with a vengence!

Having a full sense of accomplishment, I can finally put this to rest. Well, actually... I'd still want to put the new monitor in it and fix the 'invader hit' sound... reflow the motherboard sockets... powder coat the coin door, monitor PCB chassis and brackets... repaint the cabinet and replace the control panel and t-molding. Ya' know, just a few finishing touch ups. ;) Either way, stick a fork in me... I'm done with the montior restoration!

8/5/07 - Fixed 'Invader Hit' Sound

I replaced all the LM3900's and the sounds up and popping! I'm gettin good at this 'lectronix'. ;)