Fire Shark Arcade PCB Repair - Sprite Corruption 

You want to connect the logic probe up to a 5V supply source and Ground somewhere on the PCB or JAMMA harness, not an external supply. The probe uses the board's supply voltage as its reference for a High versus Low reading. I usually connect the probe to the Vss and GND on an EPROM or TTL Logic chip that I'm not probing, or on the JAMMA connector itself. The alligator clips on my logic probe are a little too large to stay connected to an EPROM easily, so I use a test clip - that's the white box with springs on it in the video. A test clip clamps on top of one the chips and makes it easier & safer to access the pins on the chip underneath.

I have no idea. I haven’t done any research or work on vector arcade boards.

@@ShootTheCore ok thanks

They're nothing fancy - I just got them from Amazon. Type "electronics tweezers" into Amazon Search and you'll have a bunch of options come up.

Masked ROM: The hexadecimal code is permanently etched inside the chip at the factory. Masked ROMs are the least expensive option for large production runs. EPROM: Erasable Programmable ROM. More expensive than mask ROMs, but used for both small production runs, or for code that was likely to change at the last minute. Most home game cartridges use only Mask ROMs, while arcade boards use a mix of mask ROMs and EPROMs. PROM: Programmable ROMs that can only be written once. Very rarely used in arcade games since they cost more than mask ROMs and weren't rewritable for last-minute code changes like EPROMs.

@@ShootTheCore thanks i'm just confused on the difference between a Masked ROM chips compared to a normal ROM chip & a PROM. It seems that a PROM, Masked ROM & normal ROM chips can only be programmed written to one time, the only difference is the price and data size the chip can hold it seems.

The H.A.S - Home Arcade System.

The MAME project has done a wonderful job over the years of cataloging and emulating arcade games. As part of their preservation efforts, they have checksum values available for each ROM in their arcade database. When I dump the ROM from my board, I compare the checksum of the dump against what's in MAME. If they match, then I know the code in the ROM is good. As for the in-game diagnostics, every game has a unique diagnostic routine. Check the manual for that board and see how to access the test mode. Some games have a special jumper you set, DIP switch setting, or a button your press. Other games make you press the Test button on the JAMMA harness. Since each game diagnostic is unique, some games have better diagnostics than others. Some games check the ROMs very throughly while other games hardly check them at all.

@@ShootTheCore yes i understand but how did they get these checksum values? do you just add up all the ROMs contents data? When i read a ROM chips contents all I see is Hexidecimal values for each ROM address location on the software screen. I can't tell where the arcade games test diagnostic program starts or ends or which hexidecimal values are bad or wrong. How would you troubleshoot ROM chips if you didn't have the checksum values or ROM files from MAME? Most arcade power supplies use one filter capacitor 27,000uf microfarad capacitor, any reasons why such a very large capacitance value to be used it seems very large because most power supply use 4 filter caps at 10uf to 100uf at the most.

@@billwilliams6338 Q: yes i understand but how did they get these checksum values? do you just add up all the ROMs contents data? A: The checksum values can be calculated from the ROM dump using a CRC32 calculation utility like this: esrg.sourceforge.net/utils_win_up/md5sum/ Q: When i read a ROM chips contents all I see is Hexidecimal values for each ROM address location on the software screen. I can't tell where the arcade games test diagnostic program starts or ends or which hexidecimal values are bad or wrong. A: Yes, depending on which ROM you're looking at, it can hold compiled & assembled programming code for that board's CPU, or binary game assets like art, music, sound effects, etc. Each game's diagnostic program will be buried in all of that, and it will be different for every game. If you want to learn more about how a game is loading assets and how the diagnostic program is accessed, dig into the MAME driver for the game, and look at MAME's ROM loading and debugging functions. Disassembling the hexadecimal in the ROM back to to the original code requires a lot of knowledge of both reverse-compiling and assembly language for that game's CPU model. The MAME devs already did a lot of that work for you. Q: How would you troubleshoot ROM chips if you didn't have the checksum values or ROM files from MAME? A: You can troubleshoot whether the ROM is outputting data using either a logic probe (like in my video) or with a logic analyzer. Otherwise, dumping the file, calculating the CRC32 checksum and comparing the checksum to the MAME checksum is your best bet. The MAME checksums are widely available - there's nothing secret or proprietary about them. Q: Most arcade power supplies use one filter capacitor 27,000uf microfarad capacitor, any reasons why such a very large capacitance value to be used it seems very large because most power supply use 4 filter caps at 10uf to 100uf at the most. A: I haven't worked on arcade power supplies, nor am I a formally trained electrical engineer, so I don't have an answer to that question. Electronics is all a hobby for me, and I'm self-trained and learning as I go along.

@@billwilliams6338 you can also run mame like so: mame -romident And it will id all roms, and even use another mame utility called romcmp to compare sets of roms

I bought my JAMMA harness extension from "frank_fjs" on the Arcade Projects forums. "The Spaniard" on the Shmups forums sells them as well.