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About this blog

This is just a blog for me to store my repair logs. I think it would be useful to others here if I post them as I am doing more repairs on arcade PCBs.

Entries in this blog

Atari Centipede - No Boot

Last repair from today's pile of Centipede boards. This one kept on resetting when it loaded the initial mushrooms. One thing I noticed is that all the legs on the ROMs were corroded, so first thing I did was clean them using TarnX as the legs were made from silver. Just as a note, the easiest way to tell whether or not the legs are silver are if they turned black from corrosion. Normal EPROM legs will not do this. Even after cleaning the legs, the game still would not boot, so th

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SNESNESCUBE64 in Arcade Repair

Atari Centipede - Quiet/Distorted Sound

This isn't going to be as much of a log, but I had a centipede on the bench with really quiet and distorted sound, it ended up just being a bad LM324 preamp at K10. The way I troubleshooted this one was literally by stacking a known good one right on top of the bad one. I did a little video to showcase exactly what I am talking about:   Edit: just to emphasize how common of a failure this is, I worked on 8 centipede boards today, 3 out of the 8 had a bad/failing LM324. It's g

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SNESNESCUBE64 in Arcade Repair

Atari Centipede - corrupted graphics

This was probably one of the quickest repairs I've ever had. I got a pile of Atari Centipede boards I needed to test and get up and running, what's nice about that is that I can swap things around quickly. First board I looked at had corrupted graphics. The game was running just fine, but the sprites were all wrong. Some were fully corrupted and most were completely wrong. So with centipede, it has two 2516/2716 equivalent ROMs for storing the sprite data. They are located at F7 a

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SNESNESCUBE64 in Arcade Repair

WG U5000 Monitor - Vertical Collapse

The U2000/U5000/K7*00 series of monitors are some of my least favorite monitors to work on. They produce a nice image when working, but that's the tough one, they have a lot of flaws. For example, they drive the neck transistors really hard, causing them to get really hot and singe the neck board, which makes it a nightmare to replace the transistors because the traces pull right up. It also has a pretty flawed design with the vertical deflection circuit. The way it derives the voltage for the t

Vision Pro MTG-1901 - No High Voltage

Quick fix on a monitor I picked up recently. When I got it, it would not power up fully. I noticed that I could hear chatter when I gave it a video signal, but ultimately got no neck glow (heater voltage) and I didn't hear any high voltage, so a serious power issue was happening. Upon closer examination, I noticed there were a couple capacitors that had bulged at the top, and that a transistor had gotten very hot, enough to singe the board. After replacing the two capacitors that

Midway Space Invaders Deluxe - Sprite Errors

It's been a while since I did an actual board repair, but this was a cool one. So I was testing a midway space invaders deluxe and noticed that there were whole lines in which there were no pixel data for all sprites. There would actually be other graphics glitches where lines would just appear randomly.  Since the game actually booted, I went ahead and burned myself a copy of the space invaders deluxe V1.3 test rom. This is where having some 28C16 EEPROMs around is super useful, I don

G07 Monitor flyback issues

This log is actually a two-for-one as it was for two seperate monitors (I've been in a monitor repairing mood as of late). G07 monitors are my absolute favorites to work on as they tend to be fairly reliable after being serviced. However, they seem to always have issues with their flybacks. To give a brief summary of what the flyback does, it is the transformer on the circuit board of the monitor that generates the high voltage needed to create a the beam that draws to the phosphors as well as o

Track & Field - Running forever

Here was a fun one, several months ago I worked on a track & field pcb that was having some werid issues. The first issue was that the game refused to boot. What this ended up being was a bad interconnect ribbon cable. Easy enough fix. The second issue was that the game would actually run forever on the 100m. Typically it is supposed to end at some point, however in this case the runners just kept on going, going to a black screen until it timed out. This was a quick fix, the problem wa

Hantarex MTC-9000 - No picture/heater

So I recently picked up a Hantrarex MTC-9000 9" (manual says it's 10", but it's definitely a 9" tube) CRT. Initially, the tube had a lot of gunk, a chip on the face of it (not really visible in the pictures), and did not work initially. This thing was used most likely in a poker machine based on the burn on the screen. I love little CRTs like this, they make excellent test monitors and I think I am going to use it for a future project. Just as a general disclaimer, CRTs are very dangerous t

Street Fighter 2 Pinball - No Sound

Something a bit different from the usual arcade repairs, recently I picked up a Street Fighter 2 pinball machine (my first pin). It was a wild ride fixing up that, but that's a writeup for another day. As the title states, the big problem at hand was that the table was not putting out any valid sound, there was buzzing but none of Guile's theme or whatnot.  So in Street Fighter 2, it utilized the Gottlieb System 3 boardset. This utilized two different sound boards, a large main sound board

Galaga - No Boot and Sound Issues

This Galaga board was a two part issue. Hooking up the board, the game booted to a white screen and zeroes.  First step whenever you get some garbage like this is to check the signals on the CPU, make sure there are no stuck signals line reset, NMI, or other critical signals. Everything checked out fine, so the next step in this case is to check the ROMs. Verifying the ROMs on my programmer, I found that all were good except 3N, which wouldn't read anything back, completly dead. After

Nintendo Radarscope -Graphics and Sound issues

This was a repair I was super excited to do. For some background, right now I am in the process of restoring an original Nintendo Radarscope arcade cabinet. The cabinet is in super nice shape but was missing several things. Anyway, when I got it last night, I excitedly had to wait an hour for the boardset to warm up as it had been sitting outside in the fridged cold. When I first hooked it up, the game did not boot properly, only showing upside down 2s.  The first thing I did to

Donkey Kong - Distorted Thump Sounds

This is actually a followup to a previous repair log I did on a previously repaired Donkey Kong boardset. Reason being is that last night I decided to run the game overnight to verify that the game will be reliable. Unfortunately when I ran the game this morning, the thumping sound that Donkey Kong was very high pitched, almost like a beep. When I power cycled the game, it was no longer a higher pitched tone, but rather a low distorted tone (closer to the actual thumping noise). First thing

G07 Monitor - Kicked Neck++

This has been a project I've had for a while. Basically, I had aquired a g07 arcade monitor had it's necked, killing the tube. Being the nature of it, I really wanted to bring this thing back to life. For reference, I've had this project since the end of october, and I just now finally finished it, shows how behind I am... So the first step here, find a donor CRT. Compatible 19" tubes are starting to get harder to find. Fortunately, I had a broken tv set with a tube that had high life

Donkey Kong Jr. - no boot

This was a quick one that I did. I recently got another DK Jr boardset as part of a trade for a working one. To make the long story short, the game wasn't running.  The first step whenever you get a game that isn't booting is to check all the control signals such as reset, clock, NMI, Interupt, ect. If any of these are not functioning properly, then you are going to have issues with the game not booting.  So I checked all the control signals, everything checked out perfectly, ever

Galaga - sprite color issues

Here's a quick one. I wasn't going to do any repairs tonite, but I was pretty bored so I figured I'd start testing a pile of arcade boards. On the bench is a galaga. After cleaning the chip legs of the customs (they are always corroded), I fired up the game. To my suprise it booted up just fine!  The problem was that some sprite colors were off, specifically any of them that move such as the ship and the bugs.  Thinking about the issue, it dawned upon me that the sprites ar

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SNESNESCUBE64 in Arcade Repair

G07 Monitor - no picture

Here was a quick repair I did last night. It was on a G07 arcade monitor that came out of a centipede cabinet. When tested on the bench, I got no picture whatsoever. Looking closely, I heard no high voltage and saw no neck glow. What's nice about the G07, is that it is one of the easiest monitors to work on, it is as simple as unplugging thing the yoke, degauss coil, and anode cup, then remove two screws. Afterwords the chassis will slide right out! This monitor was in pretty good shape, it seem

Donkey Kong - No Boot

So I had gotten some semi-repaired boardsets off KLOV last week. I've been wanting to get another Donkey Kong boardset for a while since I plan on getting a cabinet soon. Both boardsets did not work, both having different errors. When hooked up, it booted to nothing. First thing I noticed was that a bunch of chips had been socketed. None of the sockets were in good shape (one was an old nasty machine pin socket, another was a damaged dual wipe, and there were two terrible single wipe sockets), s

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SNESNESCUBE64 in Arcade Repair

Fluke 9010a - display problems

So for a long time I have been saving up for a Fluke 9010a, an in-circuit debugger for systems that utilize microprocessors such as the 6502, z80, and many others. It is a popular peice of test equipment for folk who do repairs on vintage arcade boards as it is super useful for debugging hardware problems. So I had finally won one in an auction, only problem is that it was having display problems. problem was that segments were stuck on, which tells me the display tube was good.

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SNESNESCUBE64 in Equipment Repair

Happ SE-M21C - Horizontal Jitters

So this was a quick one. I got a monitor about a month ago as just a tube and chassis, as the original owner wanted to keep the frame. I assembled a new frame out of the sides of what I believe was the sides of a WG19K4900 and the base of a G07.  After it was all assembled again, I jst needed to test it. Looking at the screen, it was obvious that it had a case of the jitters. I also realized I plugged the yoke in the flipped image plug.  After looking closly at it, I notice

B&K 467 CRT Tester/Restorer

This is a bit different than what I normally do, in fact this is the first peice of equipment that uses a vacuum tube in it that I have acually worked on. So for those unfamiliar with the B&K 467, it is a peice lf test equipment meant for analyzing the health of CRT-based displays and if necessary, attempt to "rejuvenate" the tube in order to squeeze a bit more life out of it. It is particularly useful in the arcade world as many of those cabinets still have a well-used CRT in them. It is ca

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SNESNESCUBE64 in Equipment Repair

Pac Gal (Pacman Board Hack) - Video Mess

Here was a quick repair that I did this morning. About a year and a half ago I bought a pacman board that had been hacked to run a version of Ms.Pacaman without the auxiliary board. This was done by adding two extra ROMs and modifying the code a bit. As well as running the additional lines for different enables and cutting a trace so it could address the two extra ROM chips as shown in the bottom two pictures. So I hooked it up for the first time the other day, and saw that there were graph

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SNESNESCUBE64 in Arcade Repair

Popeye - Bad CPU

This one was probably one of the quickest fixes I've done. I ordered a Nintendo Popeye board as I saw it rather cheap. I got it, hooked it up, and got no boot. First thing I do in games that don't boot like this is reseat all the chips and swap the CPU (if I can easily do that) with a known good one. In this case, I only reseated the ROM chips on the CPU board and replaced the Z80 with one of my new old stock ones I bought recently. After doing such, it booted right up! Tur

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SNESNESCUBE64 in Arcade Repair

Missile Command - Graphics Troubles

This was a fun one as it was very interesting problem. The game itself worked suprisingly. However, there were issues with the graphics.  To me, this looks like an addressing error, as the game is fine but the graphics aren't quite there. I figured that it was a problem in the decoding. As shown in the schematic snippet below, this 7442 helps control which ROM bank, RAM, POKEY sound chip, or the user inputs like the trackball. Ultimately the bad chip ended up being this 744

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Donkey Kong Jr - Mostly graphics problems

So this was a boardset that I got from 8_bit_guerrilla as he no longer needed it. When he bought it, he got it from a seller saying that it had minor sprite issues. I think the seller lied a bit, because it was a bit more than minor. Essentially, the positions of sprites were all goofed up. On top of that, the original braze kit (an old one mind you) also no longer worked. The first step I followed was finished converting it back to stock, which was a simple as removing the leftover bodge w

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SNESNESCUBE64 in Arcade Repair

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