SNESNESCUBE64

I'm down. Skipped last year but I am ready to go for this year!

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->90->81->80->71... The big thing that I was asked to do was hook my Fluke 9010 to it just to check. I originally wasn't going to be looking into this much due to lack of available time. But I told him if the fluke pointed out something obvious I would try some things. Basically, first thing I did was do RAM short tests. Typically if RAM has something wrong it will fail during the short test. I tested both the scratch and video RAM as that is all the CPU can both read and write to. From I read the ROMs just to get the checksums, the goal was to be able to see if it matched what was in MAME. However, before I did the comparisons, I did RAM long tests, which is a more thorough RAM test that the fluke can do. To my suprise the video RAM was would fail about 20 seconds or so into the test. So if the video RAM was flakey, it means that things like counts could get messed up. Looking at it, there are four sets of RAM chips. Scratch RAM - six 2111 Video RAM - two 2114 Color RAM - eight 2102 Background/stars - three 2102 In my experience, 2114 SRAM ICs can be incredibly problematic. When they start to go they can flat out fail or be inconsistent. So I just went ahead and socketed/replaced them. After that, I fired the fluke back up and performed the same RAM long test, this time it succeeded. From there I ran the game with the fluke and saw that it was counting just fine. Glad that worked because I wouldn't have had much of an idea on where to go from here.

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 that it was good. Next step I did was just swap the RAM chip. All the RAM chips on the main board are socketed and I had one on hand. So it was an easy check. Still not working. The next thing that I checked was the 74153 MUXs, they are responsible for addressing of the RAMs and after doing some reading they are common failures. Checking all the outputs, everything looked correct except for the output of pin 7 on 3E. On the oscilloscope, it was looking like either just noise or that it wasn't going low enough to register as a logic low. Regardless of that, it looked faulty. Pulling it out of circuit and testing it, it seems to have failed. Now that it has been replaced, it seems like the game is working just fine.

Updated my coin mod to be a cleaner mod. I made a tiny pcb (as small as oshpark will let me make). Also made an updated version of the power supply breakout to utilize the RQ-125B instead of RT-125B. It eliminates the need to include an inefficient 7905 on the breakout. Making it this was also reduces the size of the board.

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 data from the other segment) then you probably have a bad digit drive transistor. In this instance it is a stuck segment. We can see that the bottom segment, or segment d according to the schematics. Looking further at the schematics we can see that segment d is driven by Q16. Replacing Q16 ended up correcting the issue. There other failure points on the module, such as cold solder joints on the connector and a bad BCD chip. Reflowing the solder joints on these modules should be a given. It is very important to do such otherwise you will get inconsistencies ranging from improper display data and flickering digits all the way to nothing at all. When the BCD chip fails, I've seen it to where it will display either all 8's or nothing at all. But individual segments can get stuck as well potentially.

I have a bachelor's in both Computer Science and Computer Engineering. The Computer Engineering side is what really helped me with digital logic and whatnot. PCB design I am mostly self taught. I am a software engineer by trade but work as a arcade/pinball technician as a side hustle. The eventual goal is to be able to do pinball and arcade work full time, but that is long ways away. In terms of actual troubleshooting, I am self-taught. I've used lot of resources online. I have gotten help from several knowledgeable folk online and also have gotten help from a handful of local folk. Forums like KLOV are nice places to soak in info as well as reading other folk's repair logs. I write these with the hope that they can be used as reference material for people in the same boat. I'm still a firm believer that you don't need professional training or proper education to become a tech.

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 their use of EPROMs. Unfortunately, these use 2708 EPROMs. Problem is that none of my programmers can really read these due to them being goofball tri-voltage chips. My solution was just to replace all of them with chips that I can program. What I did was make an adapter board that combines a pair of eproms into one. This reduces the chip count and I was able to program my free play mod onto it as a result. It also assisted me in this repair as it garunteed that I had good ROMs. Testing with the new ROMs, I still was getting no boot. One thing I like to do with games that utilize 4116 tri-voltage DRAMs is to socket them. They are very high failure compared to other RAMs, so having them socketed on my games is nice. One thing I did find is that several of these RAMs were faulty. I decided to replace the entire bank of 8 to ensure the timings were all the same. Trying out the game, it still wasn't booting! One thing I like doing is checking all the signals coming in and out of the CPU, in this case an 8080. Everything looked fairly normal on the 8080, so I moved to the address buffers since it's an easy thing to check. On Space Fever/Helifire boards they are buffered using 74LS08 AND gate chips. One input is always tied high for each gate, so they just act as a passthrough. To my suprise, A8 was stuck low despite having a pulsing input. Input: Output: This is a very obvious problem, either the AND gate there was faulty or something in circuit was pulling A8 low. I went ahead and simply replaced the 74LS08. This chip was what was holding the board back. With a new one it now boots as it should.

Elvenking is a neat band. I think Pagan Revolution is my favorite song up to this point.

Forgot about that. Wonderful.

Very anti-consumer. Although microsoft is a big fan of that kind of practice. I also think that maybe there would be a class action because of this.

Excellent choice with Symphony X. I listened to a lot of them in High School and have been listening to them more recently. Smoke and Mirrors is an excellent choice. My absolute favorites are all on Iconoclast, although that is one of my favorite albums of all time. I got to see Symphony X live last year, it was a hell of a show. Although I don't think that "The Odyssey" is a great closer, especially when they are starting it at midnight and you gotta wake up for work at 5:30AM the next day.

Flash gordon, like a lot of games from that era and before that, are brutal. This was actually the first pinball machine I ever worked on actually. If memory serves it was because of sound issues. Another really fun one from that era (in my opinion) is Flight 2000. Love it to death.

So because I am under thirty I am not able to recognize a game as influential or important and have fun with it? Nowadays the "classics" have been available new a number of times on various platforms, so many of us have been able to experience them. For example with me I played the Mario Advance series growing up, which were just remakes of "classics" plus mario bros (my favorite arcade game because of that". Part of what makes some of these games truly classics is that they span generations I think.

Couple weeks ago I picked up a Nintendo Helifire cocktail table. Finally got it working tonite.

Finally got the board working enough to test my mod. Super happy that it is working as it should.

I think it's the sugar and salt combo because I feel like that would actually be pretty good. Kinda like putting salted peanuts in a bottle of coca cola. It's a weird combo that tastes surprisingly good. I'll have to try it.

Coffee isn't for everyone either. I only started drinking it because it was free. Also, I finally have a way to describe candy corn: it is the la croix water of candy.

I used to have a street fighter pinball. Had to sell it so I could get more arcade cabs.

No I quite enjoy coffee.

Candy corn is one of those things that I've never understood. Not a fan. Dunno maybe it's like enjoying coffee or something.

Dunno how I missed this topic but without reading anything (even this whole thread) or looking into this at all, suddenly my crackpot conspiracy theory that wata grading is being used for money laundering finally has some credibility.

I feel the exact same way about them. I don't know what it is is but I can never vibe with their sound. They got a few bangers like "hunting high and low" and "Paradise" but I just can't get through so many of their songs. A couple songs from their newest album are good, like "Survive".

So a few days ago I obtained a Nintendo Helifire cocktail table. The problem is that I like having all my games on free play if I can help it. Mainly because I don't want to keep a bunch of quarters around. Helifire unfortunately does not have a free play mode, so I had to mod the ROMs in order to support it. It was pretty interesting altogether. I used the MAME debugger to go through the disassembly in order to figure out what routines did what and where coin stuff and start stuff happened. The approach I took was to remap the coin switch to the start buttons, rewritting the routines to determine which button was press to add an appropriate amount of credits. From there I set up the game to autostart after coin insert. I tried just jumping to the start of the game but that did not work, it does some goofy stuff when it goes through the coin routine. After rewriting the routines to do act as a free play, it was just rewriting the "insert coin" and "credits" text. This is what I ended up with. I only ended up needing to change two of the ten ROM chips to support it. One with actual code and the other with the free play text. This was a bit more complicated than the free play mod I had to write for Head On N. I can't wait to try this on real hardware, I just have to fix the game board.