Last updated: July 02, 2002 - Galaga pages updated.
 

Galaga (Bally/Namco, 1981) (Page 2)

 

Cleaning and Repair (or, I learn how not to fix component-level electronics stuff)

The Mini:

    As this section is still in-progress, here is a status report of what I've managed to do so far. Upon opening the back of the mini, I was astounded at how much dust there was inside there! I couldn't even SEE some portions of the monitor guts, cables were covered with thick layers of the stuff. I took a rag and some 409 and went to work on the inside of the cabinet itself, then worked on cleaning the monitor glass. Dusting the parts off was somewhat time-consuming, but educational. Like the games I've worked on before, this has a power supply, a power filter, coin lights, etc. Unlike the other games, this monitor was easy to work with, since it uses plug-in PCB cards rather than having EVERYTHING bolted to the chassis. I took the two boards off, got the engine cleaner/degreaser, and a big bottle of rubbing alcohol, and thoroughly cleaned the boards. Once I could see what I was doing, I attempted to find the horizontal size adjustment control, but was unsuccessful. Later, I found it was a coil, rather than a knob or dial like the others. Great, why do they have to make these things more difficult than they already are? I've ordered a cap kit for the monitor from Bob Roberts, and should get that next week sometime. Hopefully that will correct the graphics-falling-off-the-side problem. When I had my co-worker over to bring in my Joust 2 game, he took a look at the monitor, showed me the coil, then discovered a cut wire on the monitor cable that could be causing some problems as well. It looks as though I may have to either find a replacement or re-wire portions of the cable myself.

    The power supply is definitely a source of concern to me. It's been fried a couple of times, if the condition of the plastic connectors is any indication. At one time, someone disconnected some wires from the J1 connector, and soldered the wires onto the BACK of the power filter PCB. Nice. I wouldn't be a bit surprised if the power supply was what was causing the random resets. But, I went for the obvious "get-well" fix, playing with the board set. I noticed the video board especially had many RAM chips that had silver leads, and were quite corroded. This can affect power draw and heat production, so I decided to unsolder them from the board and give them a nice Tarnex bath. I made one possibly fatal error - I didn't write down which chip numbers went with which spot on the board. I got them all back in more or less where they were supposed to go, but had some more problems besides that. It turns out that many of the chips on this board had been replaced at one time, by someone who was a little less careful than I was with the de-soldering iron. One section of traces was completely gone, with at least 4 jumpers run past the bad spots. Also, they had burned off the solder pads around the holes for the chip legs, so while getting the solder off was easy enough, soldering the legs back in was a different story. I managed to destroy another damaged trace, and took about 2 days to get everything back together. Want to know what can happen to a video board when some connections aren't made properly?

1. Upside-down video - Yep. First time I put it back in that's what I got. It was playable, but not right.

2. Video split into two horizontally - I had 2 playfields split 70/30.. Foreigner's "Double Vision" was playing when I powered it up like this. I think it's haunted.

3. No sprites - The current state of the board. I a normal screen, with text and the scrolling background, but no ships or bombs. Strangely, the Galaga's tractor beam IS visible. The game does play blind, and I have completed Stage 1 like this. I will be comparing this vid board with that of the UR to see where I have gone wrong.

July 26, 2001 update:

    I had the game working for a while, but it was still flaky. Once I got the chips in and soldered correctly on the video board that is. Unfortunately, soon after this I began having trouble with the game's power. Fuses kept blowing on the filter board, so I decided to change over to a switching power supply. After that rewiring was accomplished, same problem. I think it's the wiring harness for the CPU board's edge connector, there's parts missing or not wired correctly. Unfortunately my schematics book went for a walk, so I've been using a scanned-in version I found on the 'net. It's hard to read, and doesn't make a lot of sense in a couple of places. I put out an SOS, someone gave me a sanity check on the wire numbers and colors. I plugged it all back in and.. nothing. I tracked the problem down to a broken clip on a fuse in the bottom of the cabinet. While I was removing the clip assembly, the 115v DC wire fell off, so I'll be doing some re-working of that. With luck, all my recent problems are simply a power issue, and everything will work PROPERLY by the time I replace this piece.

July 2, 2002 update:

    Game is currently completely working. Fun with flaky boards: I had sent this set off to be repaired. Got it back, and it worked for 10 minutes then blew up again. Traded the boardset for another, known good working set and tried things, no problem! I had wired everything almost correctly the first try, and had merely to make sure the ground for the control panel and coin door was properly wired. Replaced some burned-out bulbs then turned my attention to the flaky monitor. After a few minutes it would flicker then start going crazy. Definitely a vertical deflection problem. I found out what transistors and caps on the K4600 monitor were responsible for the trouble, and replaced those. Sure enough, that did the trick, and it began working again, much more solidly than it ever did in the past. Yeah!

The Upright:

    A much shorter section, as I have only just recently had the UR in my possession. I have tested the boardset from this one on the mini, and it seems to work fine except of course for the annoying rapid-fire feature. I'll be changing that ROM out for an original, 2-shot-at-a-time ROM shortly. I know the power supply works (this one is a switching, yea!) but haven't had a chance to investigate the monitor problem. I hope it's something relatively simple. If not, I know where I can get a new monitor for cheap :) I like the full-sized games, but having two mini-cabs by Bally side-by-side is too cool, so I'll probably E-bay this machine to get back some money I spent on getting the games and of course, to pay for household items this bachelor has never needed before, like curtains, and dishware.

July 26, 2001 update:

    This baby is gone, gone gone! I didn't Ebay it, but instead took it to the April 2001 Indy auction. Got $650 for it, before sellers fees, etc. Not bad, I wish I had it back though, what with my troubles with the mini! Here's what I ended up doing with the game to get it going.

    No voltage was getting to the monitor at all, so I checked out the caps, bought some new ones to replace the ones that looked like they were old. It was easy to tell which were old, they had 20 years of dust on them. Powered it up and... nothing. Then it sat for a couple of months gathering dust. I took another look at it, decided it needed new fuses as one of them tested good but looked like it had exploded internally, weird. The fuses had leads on them, and I couldn't find new fuses with leads, so I bought some of those little fuse holders. Unfortunately, the holders I bought were too small. So, the monitor sat another month. I finally got around to getting the correct-sized fuse holders, soldered them in, inserted the fuses, and... TA DAA! There's a picture!

    I took it outside to paint the sides black again, after first covering over the sideart. The kickplate art was indeed relatively intact, but covered by black stickers. I removed the stickers using warm water, a sponge, and my fingernails. Ugh. But, by the time it was done it looked pretty decent. I moved it inside, powered it on, and...

    SNAP! Picture died... then came back a second, then died again. I walked to the back of the game and smacked the side of the game, and saw the SNAP came from the monitor's.. what is it called? I'm not sure, but it's a little red coil of wire, looks suspiciously like the thing I thought was the horizontal size adjustment control. It's not, it apparently has a lot of voltage going through it? Anyway, one end of it was not soldered down properly, so it was loose. Every time it moved it fried the connection. So, I got to power down and use that most wonderful of tools, a big giant screwdriver with a ground wire.

    Once the tube was discharged, I had to solder down the wire's end. Easier said than done, but I eventually got it done. I got a friend to help haul it to auction, then plugged it in once I got there. It still worked, but there was a bit of a short on the wiring to the switching power supply - jiggling the wires got the power back on properly after a bit, but re-wiring on the spot was out of the question, I just had to make sure it stayed powered on during the showing period the next day. The rest, as they say, is history.
 
 

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