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Everything posted by channelmaniac

  1. Never mind... found it thanks to the Internet Wayback Machine. It had a good version of the page from last year with the email address for submitting the code dump. 🙂 Super Space Invaders 91 (Majestic 12) US Region, complete with the "Don't do Drugs" screen and legal warning about US use only has been submitted!
  2. Repaired a PCB tonight with a US region ROM version that isn't in MAME... and the site with the submission info is borked. https://wiki.mamedev.org/index.php/Submitting_Source_Code Can anyone PM me the email address to submit the ROM dump?
  3. Depending on the model, it might not be repairable. If it has a surface mount Z80 chip the only source would be a donor Sega Game Gear. Luckily those are on very few models and most use standard 40 pin DIP Z80A CPUs. 🙂 Usually the problem is a dead Z80 CPU. Do you get the same error with no cartridge(s) plugged in?
  4. Gave the AA forums a shout out in my video description here.... This is the first video to be made from this series of short posts. I hope you enjoy! If you don't enjoy, please tell me why as I'd like to always improve. 🙂
  5. OK! Got the first topic ready to be recorded on a video... but before I did that, the folks on the Dallas Retro Computer group on Facebook asked me to teach them about monitor repairs. It took me a few months to build out all of the slides, but I put together a presentation and it was done over Google Meet and recorded wtih Camtasia. Hope you enjoy!
  6. Hey boss, those TI chips rust because they are built like Namco customs - steel legs with silver plating on them.
  7. Yeah, if the music works then your Z80, YM2151, and the HA13001 are all working and don't need replacing. That leaves the OKI chip, the 2 sound sample ROMs on the B board, the interconnect between A and B board, and the passive components around the OKI.
  8. Unfortunately, you'll need another boardset to swap things around to narrow it down. The C boards are common failure points as is the custom chip on the A board.
  9. Not a super cap... When that goes out your sound settings are forgotten and don't match what's in the EEPROM... They usually end up at full blast. Hold down the volume down button while you turn on the game and hold it until you see the splash screen. That will reset tha audio. It happens sometimes when you swap carts around. BTW: This is Capcom CPS2, not System 11.
  10. A Unibit / Stepped bit works as well, but you have to be very careful the hole doesn't go offcenter.
  11. Y'all in Down Under have been kind to this outsider from Up Over so I sent ya a bit of PayPal love. Hope it helps.
  12. There are 4 74LS161 or LS163 chips at 2R/2S, 3R/3S on the PCB... check them for failures. They are common failure points and are clock dividers necessary for proper operation of the board.
  13. If you have the Midway 8080 L board for SI, I have the strapping documented.
  14. LS14 should be it... they are Schmitt Triggers which take a slow ramping input and squares it up Those are the first to replace if you can't get inputs from the guns. They are the first in line to get zapped.
  15. If the filters are all good, check to see if there's a 74HC14 on the PCB... That is common on gun games to square up the inputs and is a common failure item. If it failed then make sure the armored cable for the guns are grounded properly. Static is not kind to HC (High speed CMOS) chips...
  16. Lots and lots of bad solder joints on the SPI surface mount customs... Start there with reflowing. If you don't know how, send it to Womble. Also, since this thread was bumped... you don't always have to remove the Flash ROM now if the region byte was corrupted... There's a program to help with that but it's not supported on all game carts. https://bitbucket.org/trap15/spi_revive/
  17. Check the SMT filters for continuity on that interface PCB... and make sure you have +5 going to the gun to power it.
  18. Jungle Hunt and that series isn't too bad to repair. I stay far away from Zoo Keeper, Joust, and the others that spread out all over the bench. For Jungle Hunt, Elevator Action, etc... the key is to read the EPROMs, checksum them, and if correct, program the data back to them. For ones that aren't correct, reprogram them with the proper code. Those EPROMs on those boardsets like to suffer from bit rot for some reason. I find the older Sega boardsets like Choplifter and Wonder Boy suffer similar bit rot, but also leg rot with the dissimilar metals between their gold alloy sockets and tinned pins of the ROMs.
  19. BTW: Your audio replacements worked beautifully on a fairly rare Polygonet Commanders board... once I replaced the failed DAC. :D That is such a fun and underrated game, especially in multiplayer linked cabinets.
  20. Not with leaving the old suicide CPU in place on the board...
  21. Clock, Reset, stuck IRQ, bad ROM, bad RAM, gouged traces, all those are suspect before a 68000 CPU in my book. They are that rare to fail.
  22. First... How have you cleaned the boards and carts?
  23. Probably a bad custom IC on the A board. :( Only sources: Another A board or a CPS 2 A board.
  24. My main pieces of test gear are a logic probe with audio beep (modified with IC grabbers for power tapping), a Radio Shack DMM with transistor test mode, an HP 10529a logic comparator, and an ESR meter. Those help me fix 99+% of things. I have a crapload tied up in chip testers, Fluke 9010a/pods, Fluke/Keysight/Agilent DMMs, Tektronics/Agilent/Keysight oscilloscopes, and Pace soldering/desoldering stations on my three shop workbenches, but I started with that RS meter and am very used to it. http://www.datasheetarchive.com is your friend when working with obsolete parts.
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