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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 arcade and pinball repairs.

Entries in this blog

Nintendo (Gremlin) Space Firebird - Sprite Issues

On my bench (technically the trashcan next to my Helifire table) was Nintendo Space Firebird. This one was specifically the Gremlin license but they are the same game for the most part. The problem with this one is that some sprites are garbled or missing. This ended up being one of the quickest repairs I have done. It probably took longer to hook up the board. The problem chip ended up being the second chip I did a spot check on: the 74ls00 at 3D. Probing the chip, I noti

Williams Pinbot - Missing Characters and Segments on Displays

Seems like I am doing a lot of display repairs as of late. This time it was for Pinbot by Williams. In this instance, it was missing the middle character for player 2 and player 4. This one is fairly easy to handle looking at the schematics. The other issue is that the credit digits are missing segments 'B' and 'D'. The first thing to tackle is the missing segments. each display unit uses it's own driver IC for turning on the digits. So it would be just finding out what is in common.

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SNESNESCUBE64 in Pinball Repair

Tektronix 2232 Oscilloscope - CRT won't focus

I have been using this scope for quite some time now and it has served me well. It is my go to for quick troubleshooting as it is quick and easy to setup compared to the scope functionality of my logic analyzer's scope. So you can imagine that I was a bit bummed out when I started having issues. Fortunately this one was a simple repair. The CRT would not focus all the way. Basically, I would have trace and text if I turned it on, but it was blurry. Typically, it would be simple in the sense

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SNESNESCUBE64 in Equipment Repair

Andromeda SS - Can't Count Correctly

This was a really goofy one that a friend sent me for repair. It's an odd space shooter-type game made by Irem called Andromeda SS. It uses M11 hardware with several mods for sound. Fortunately for me though, the CPU board didn't have many mods. The main issue is that it wasn't counting correctly. In Andromeda SS it has a bonus counter on the bottom that counts down. Basically, it starts at 99, but once it got to 95 it would count weirdly. It would count kinda like this: 95->91->

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SNESNESCUBE64 in Arcade Repair

Williams Stargate - Not booting

Today I had to work on a Stargate by Williams. The complaint was that it was stuck in the rug pattern. Taking a look at the back, I saw that all voltage LEDs were lit on the power supply. I also noticed that I was getting a RAM error code: 1-3-1. 1-3-1 is a RAM error code that is supposed to indicated that the first RAM in bank 3 has failed. It is also the first RAM that get's checked, awfully suspicious. First thing that I checked was the voltages, all were within 5% so I figured tha

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SNESNESCUBE64 in Arcade Repair

Kiss Pinball/Early Bally Solid State - Stuck Display Segments

This is probably one of the more common issues that I've seen on these old Ballys. The way these work is each display is it's own module capible of displaying a score or whatnot. Sometimes what can happen is that segments can get stuck or not light up at all. This one is from a Kiss pinball. Essentially, the way that these modules are driven can be split into two parts: digit driver and segment driver. If a certian digit is not lighting up or is stuck (many times 8 because of all the

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SNESNESCUBE64 in Pinball Repair

Nintendo Helifire - Game Not Booting

I recently picked up a Nintendo Helifire cocktail table and been having a blast bringing it up. There was one main problem though: the original CPU board wasn't working.   With this though, I was able to cheat because I knew it was a problem on the CPU board. Reason being that I had an extra, but I wanted this one working. The first thing I always do when working on a game that isn't booting is check the ROM data. ROM corruption is a very common issue with arcade games due to the

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SNESNESCUBE64 in Arcade Repair

Sanyo 20EZ - Partial Collapse and Brightness issues

This was probably one of the nastier 20EZs I've worked on. I don't know what this thing's past life was but it was pretty rusty and coated in dirt. Regardless of how dirty it was, it will clean up fine. The problem is that the picture was screwed up. It was dim in and had partial vertical collapse. You can even see some waving. One thing that is super common on 20EZs is that the electrolytic capacitors go bad. This is especially common with the higher voltage (160V)

Williams Corvette Pinball - DMD Blotchy

Game: Williams Corvette Pinball Symptoms: DMD display characters was a little blotchy Troubleshooting Steps:  Looking at the display, I could see that it didn't look like, it almost looks like the characters were blotchy and distorted. You could see dots around the characters, it was super visible in person as well. The first thing that I did was checked was the voltages that the DMD was getting. One thing that I noticed was that the -125V line was rather out of spec, I was measuring -

General Pinball Repair Logs (Updated 12/24/23)

The purpose of this is to put logs that I don't think need a proper writeup. It should be updated periodically. Date: November 26th, 2021 Game: Williams Earthshaker Symptoms: Left flippers not working, fuse F6 popping after holding down left flipper button Solution: End of stroke switch for upper flipper was not aligned and disabling one of the windings on the flipper coil. Adjusting it fixed the issue. Date: June 12th, 2023 Game: Demolition Man Symptoms: garbage on lower half o

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SNESNESCUBE64 in General Logs

General Arcade Repair Logs - updated 12/24/23

This entry is meant for simple fixes that aren't worth going in-depth about the repair. It will be updated periodically to add new entries. I only have one to start but should have more later. Date: June 12th, 2023 Game: VS Super Mario Bros Symptoms: Low scratchy sound on sub side Solution: replaced bad LM3900 at 3N Date: September 4th, 2023 Game: VS Super Mario Bros Symptoms: monitor (20ez) experiencing weird issues, small screen and low/unadjustable B+. Solution: replaced bad

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SNESNESCUBE64 in General Logs

Vision Pro MTG-2901 - DOA/clicking

Monitor: Vision Pro MTG-2901 Symptoms: Completely dead, clicking when powered on Troubleshooting steps: Like with any monitor, the first thing I do is make a capacitor kit and replace all the capacitors on the chassis. Arcade monitors work long hours and have exceeded their life in many cases. This is especially important with these Happ and Vision Pro monitors, of which have terrible capacitors. Replacing the capacitors in this instance had no real effect on the issue. Upon

Black Knight Pinball - Trashed Drop Target Coil

Symptom: Lower left drop targets not resetting when all three are knocked down. Troubleshooting Steps: The first thing that I do whenever I deal with a non-functional coil is I check the coil itself. On a pinball machine, it is super easy to do this typically. The first thing you would do is remove the lock bar and playfield glass. Next, be sure to remove the balls themselves. This is an important step, as when you are lifting up the playfield, they can free themselves from the trough, potenti

Laser War Pinball - Random Resetting

Symptoms Random reset, sometimes resetting rapidly Solution Steps Looking at the schematics, reset is controlled using a Power On Reset (POR) IC. Basically how it works is that it sends a reset pulse to the CPU whenever a threshold voltage is reached, somewhere in the 4V range. With that knowledge, I had to monitor the reset line. In this image, the reset line is yellow and the +5V rail is in blue. What I wanted to do was see if there was maybe a short or if there was excessive noise g

Head On N - Blocky Graphics

I got a pretty interesting board on the bench this time: Head On N, released by Nintendo, Licensed (Or stolen) from Sega. This is an interesting boardset, as this is for the most part a clone of Sega Vic Dual hardware, except they spread it across two boards and included the sound board on the CPU board. I had already done a deal of work deconverting the board, unfortunately this thing was missing a lot of parts and was modded to play an unknown game (the roms weren't included). On to the i

Williams Stargate - Missing/Incorrect Sounds

This was a neat one because I have not encountered a soundboard issue like this one before. In my short experience with Williams sound boards for games like stargate and joust, they have been an "all or nothing" kind of deal. This one however was missing sounds. To troubleshoot this one, I did a few things. When I booted the game up I pressed the test button on the soundboard, it should play game sounds in general, but this just played tones. What this told me was that the CPU, DAC (probably)

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SNESNESCUBE64 in Arcade Repair

Konami Hypersports - Blue Screen/No Moving Objects

This was a fun one. I have a whole box of these boardsets and I figured out which ones had working CPU boards, so I was able to immediately narrow it down to the video board. The initial problem with this board was that the board was doing nothing, just displaying a blue screen. Just randomly probing around randomly at the buffers going between the video board and the ribbon cables going to the CPU board. The overall goal was just to make sure that the two boards were talking to each

Gyruss - No Moving Sprites

First time that I've ever worked on a Gyruss. I have to say, the fact that it had any custom ICs at all kind of intimidated me a little bit. I am not the best when it comes to video issues, but is something I am working on getting better. But anyway, this was a pretty straightforward repair. So the problem at hand was that there were no moving sprites at all. Text would appear, but nothing that moved. This is great because it really helps narrow down the circuit. After doing a bit of r

Laser War Pinball - Some Flashers Stuck On

This was a quick fix as I've seen this issue before. So I was working on a Data East Laser war pinball machine, and some of the flashers were stuck on. This pinball machine just had all of its bulbs replaced with LEDs, so realistically there shouldn't have been a problem. There were also several stuck on so it was more than just a bad socket or a wiring issue. I identified the bulbs as the following:   Flashers are driven by the solenoid circuits, so it seemed odd that the flasher

Donkey Kong - No Boot/Resetting

Yet another Donkey Kong boardset that boots to garbage. This one was a bit more interesting as there were two main problems with this board. Whenever the game does not boot, I always check the ROMs and make sure that the game can read the ROMs if I can check that. The ROMs all checked out good using my programmer, so now it was time to check to see if the game board could read them. The way I check is by using a Fluke 9010a with a Z80 pod. What this does is it emulates the Z80 CPU and allows me

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SNESNESCUBE64 in Arcade Repair

Space Invaders - No boot

Yet another space invaders boardset on the bench, this time it isn't a deluxe boardset. After hooking it up it would boot to only showing one invader, not making it any further than that. First thing I do in a case like this is double check the ROM strapping so I can hook up the test ROM. This one was configured for 9316B mask ROMs, so I was able to just drop my test ROM in with no issue. From there, the test ROM told me the the exact issue, it was RAM C. Before I flat o

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SNESNESCUBE64 in Arcade Repair

Space Invaders Deluxe - Bringing Back A Parts Unit

On the bench today was a Space Invaders Deluxe that I had grabbed off the pile. This one had unfortunately been a parts unit, as someone had taken several parts off the board, probably to fix another Space Invaders board. It was also pretty dirty, so I had to give it a bath. After washing the board, my first thing was to attend to the missing parts. It was missing a 9316 (Really a 74161 counter), a 74ls04, and an Intel 3245. The intel 3245 has become a bit more difficult to get a hold

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SNESNESCUBE64 in Arcade Repair

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

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