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Here are Sega Star Jacker schematics that I've seen others use to repair Wonderboy: https://drive.google.com/file/d/1AYv91Pfp4V8LqV062SefD2vPYrT73zQM/view About the 74LS157s, the usual thing to check is for stuck/nc outputs (pins 4, 7, 9, 12): https://eater.net/datasheets/74ls157.pdf. If you...

Hi, those RAMs you replaced might be work rams, if you turn on the game w/o them, does it boot up?. If those ROMs are good, and you're sure they're related to the failing sprites, with a multimeter you could check what's the destination of their data lines, they could go to a failing logic IC...

Hi all, got a MK4 board that reports "Error 0A - Sound System Error - SRAM Failure" on boot, after that it plays fine, without sound. When it displayed that message it did bong a few times, so that would at least mean the DAC and AMP would be ok. Began by verifying the sound roms with a XGecu...

Hi there, I'm looking for just a Mortal Kombat 2 main pcb in good working condition, I already have a working sound board (my main pcb is not working good). It could be either a MK2 or MK1 (T-Unit). Shipping to US. Thanks!

@wickerwaka Thank you for sharing your research. It inspired me to go try convert my Gunforce into In The Hunt. Desoldered 9 32 pin roms, installed sockets in their places Programmed the ITH rom set + decrypted sound rom + M92_B-7H-D GAL Set up jumpers accordingly Success!

I was googling for schematics for a Tekken 2 (System 11) motherboard I have with issues and your post just showed up, for me this document makes the difference between being able to continue troubleshooting the board and hopefully finding the issue or throwing it into the parts bin for maybe...

Same flawless experience with my Volfied PCB purchase. Thanks!

Fixed. The uPD7759 was bad. Posted full repair log at https://www.arcade-projects.com/threads/konami-tmnt-repair-g8-bad-051960-custom-replacement-intro-song-speech-sound-issues.28624/

Hi guys, I got hold of an untested Konami TMNT PCB. Initial inspection was good, looks alright after cleaning with brush, no scratches with broken traces, notable details are just 2 socketed SRAMs (G8 and F23) and quite some soldering glob over each JAMMA pin, seems they were a bit...

Update: took out, tested and socketed: F15 (74LS273) used for choosing which sound to play, input comes from Z80 data bus B16 (74LS273) used for addressing high ROM address lines D18 (1Mbit mask rom) They all tested fine using Xgecu T48. Replaced the LS273 with other ones just in case had a...

Hi guys, I'm looking for some assistance on bringing this Konami TMNT board back from the dead. Got it from an arcade parts lot. It had different issues that I've been able to overcome, but got stuck on this one. Previous issues were: G8 BAD error - fixed replacing 051960 custom Title music...

Thanks. Today I reflowed the data port pins, took out U16 (DAC), U37 (TL084), U18 (74LS74) and U38 (74HC14), installed sockets. Tested the U18 and U38 on the T48, not surprisingly reported good. Installed a GoldStar 74LS74 at U37 just in case. Replaced the TL084 with a new one since it was cheap...

Hi guys, I'm having a bit of a struggle with the sound board of my MK II, game works fine, but sound board never gets to boot up properly, its LED rarely turns on. When started up or reset, most times it does something different, I mean I might get no bong, or 1, with all roms installed, prior...

Hi guys, I had a CPS3 board with the blue color missing. Basically everything looked either red, green or yellow. Color bar test screen confirms blue color is completely absent. Began troubleshooting the issue by measuring with an oscilloscope the blue color signal from its JAMMA edge pin...

Hi guys, I've got hold of a Sega Title Fight cabinet to be restored, probably haven't been turned on in many years. So as first step I took the huge metal cage from its inside, opened it and found a pristine System 32 Multi board, looks almost like straight out of factory. As first step...

Looking at your System 32 schematics I found that many websites like System16 (probably is where it started and other sites copy it) or SegaRetro mistakenly list the 315-5386 IC as "tilemap generator (backgrounds)" and 315-5387 IC as "sprite generator". Because on the schematics it is the...

Thanks. The part of your thread that says you found no continuity in certain places inspired me to do a "shotgun reflow" of the Pincushion area and surroundings. I had reflowed some critical parts (pots, crt socket, big transistors,..) but hadn't tried doing it to the small components. So after...

Hi guys, thanks for the suggestions!. I've been trying quite a bunch of stuff these last days, basically I removed, tested (everything tested OK) and replaced (just because I had parts available) every component at the pincushion area, and basically nothing changed :( Every item highlighted has...

Hi nem, desoldered and individually tested Q451, Q452, Q453. They are well recognized as transistors by the tester, and they seem to have almost equal characteristics, so seems that they're all "healthy".. Also tested D451 and D452 (in circuit) and gave ok forward voltage (0.5v). What could I...

Hi guys, I'm having an annoying pincushion issue with this Nanao MS8-26SG, some background: this issue might have started some time after recapping, I mean it used to look good after recapping but then I remember the monitor pincushion to flicker a bit by itself after "warming up", to eventually...