Numan Athletics corroded, dead & graphics glitches

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    • Numan Athletics corroded, dead & graphics glitches

      Short version: check the via to the right of c5 as the leaky cap can destroy it.

      Long version:
      Numan Athletics runs on Namco NA-2 hardware meaning that it has super leaky SMD caps that will corrode the board. Exactly that had happened, so first thing was to remove all the caps and replace them, no problem.

      Unfortunately when testing the PCB it was completely dead. When powering it up, 90% of time I got black screen, 5% of time blue, 5% of time green. Eproms checked out ok and bending the pcb or pressing down on the smd chips did not make any difference. Nothing got too hot.

      Started by scoping the 68000 CPU: CLK was okay, _HALT and _RESET are 100% of the time low so no surprise all address and data lines were dead.

      Traced the _RESET to couple of big custom smd chips, the nearest one to CPU was probably reflowed sometime in the past. I don't have the slightest idea what those custom chips do, so didn't get any further from there.

      The leaky SMD caps were in audio section but one of the SMD's (C5) was on a completely different side of the PCB - and funnily enough it was next to MB3773 which is a "power supply monitor with watch-dog timer" producing RESET and _RESET. Scoping that chip provided very weird results: weird enough that they made me to check GND of MB3773. The way MB3773 works is that pin 1 and pin 4 are connected together with a capacitor (which acts as a timer) in between the pins 1 and 4. The negative end of the capacitor is also connected to ground. I had replaced the leaking SMD capacitor, but apparently I hadn't checked the connection to ground - and it was NOT connected to the ground! The via was completely destroyed by the capacitor leak and I had no clean way of fixing the via so I did the ugly trick and put a wire from the MB3773's ground pin to a nearby ground mounting point.

      Re-attaching the rom board and connecting power made the game come alive ....

      ... but in the intro mode some parts of the left side of the screen was corrupted. It looked like one of the tile layers (just a guess) had its address lines merged (just a guess). For example the title screen was perfect, but while "insert coin"-boxes did have correct text on them, most of the font's horizontal lines were missing and some were duplicated in wrong places. Also some in-game graphics were messed up in the exact same way.

      Considering how few components the non-rom-board has, it would have been a surprise if the problem was anything else than the custom chips. I inspected the reworked custom chip first and unsurprisingly two of its the pins were bridged. Unbridged them and graphics were perfect.

      At that point I remembered that the whole thing began with the idea of simply replacing the audio caps, but the game was completely silent.
      So far the two fixed I had done were easy, but fixing this was even easier: I pressed start button and was pleasantly surprised to also find out that the audio section worked perfectly, the game just had its attract mode sound turned off :)
    • I've revived 4 of these PCBs simply replacing the cap near the MB3773, sometimes the mb3773 is dead too or has badly corroded pins and needs replace.

      You can also add a push button in this area as a reset switch, could be handy for a multi game :)
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    • twistedsymphony wrote:

      sometimes the mb3773 is dead too or has badly corroded pins and needs replace. You can also add a push button in this area as a reset switch, could be handy for a multi game :)
      Yeah, that mb3773 looked pretty bad so I reflowed it.

      About that reset switch, I guess you're right, but that's not for me: my very strict religion prohibits me from owning cars with back seats, using emulators for playing games, playing retro games on non-crt displays and using non-official multi boards :)
    • arttu wrote:

      twistedsymphony wrote:

      sometimes the mb3773 is dead too or has badly corroded pins and needs replace. You can also add a push button in this area as a reset switch, could be handy for a multi game :)
      Yeah, that mb3773 looked pretty bad so I reflowed it.
      About that reset switch, I guess you're right, but that's not for me: my very strict religion prohibits me from owning cars with back seats, using emulators for playing games, playing retro games on non-crt displays and using non-official multi boards :)
      Non-offical? Brother, on A-P, all the multi-boards made here are official!
    • This pcb seems to be a 50 / 50 to where the capacitors leak, seems you got lucky and sounds like you got to the ones near the customs in time :)

      xtrasmiley wrote:

      Non-offical? Brother, on A-P, all the multi-boards made here are official!
      Namco had there chance years ago but turned down my job application!

      It is also designed exactly to spec and the games patches are literally one liners now.
      No damaged / scrapped originals needed, no mods needed just plug in rom board socket and away it goes.

      Some people can't handle the power i guess ;)
    • arttu wrote:

      Yeah, that mb3773 looked pretty bad so I reflowed it.
      About that reset switch, I guess you're right, but that's not for me: my very strict religion prohibits me from owning cars with back seats, using emulators for playing games, playing retro games on non-crt displays and using non-official multi boards :)
      I'm OK with everything you said but a car without back seats also implies your family is limited to two people.
      Looking for:
      - faulty Hang-On, Space Harrier or Enduro Racer (2203 sound board)
      - Sega Mega-CD 1 power board
      - Super Nintendo CPU (3 needed)



      "I'd 1cc games but I have a real life."
      01010011 01000101 01000011 01010010 01000101 01010100 00100000 01001101 01000101 01001110 01010101 00100000 01000111 01010101 01011001
    • nem wrote:

      You've never seen a car with a bench seat in the front?
      I did but in Europe I only remember the Matra Baguera and Murena, and the Fiat Multipla. And of course those utility vehicles.
      Still, in most countries (at least all those I've visited), you're not allowed to have kids under 10 on the bench seat.
      Anyway that still limits your family to 3 people and no pet.
      Looking for:
      - faulty Hang-On, Space Harrier or Enduro Racer (2203 sound board)
      - Sega Mega-CD 1 power board
      - Super Nintendo CPU (3 needed)



      "I'd 1cc games but I have a real life."
      01010011 01000101 01000011 01010010 01000101 01010100 00100000 01001101 01000101 01001110 01010101 00100000 01000111 01010101 01011001
    • Apocalypse wrote:

      arttu wrote:

      Yeah, that mb3773 looked pretty bad so I reflowed it.
      About that reset switch, I guess you're right, but that's not for me: my very strict religion prohibits me from owning cars with back seats, using emulators for playing games, playing retro games on non-crt displays and using non-official multi boards :)
      I'm OK with everything you said but a car without back seats also implies your family is limited to two people.
      Some people don't want kids, some people can't have kids, and some people don't want to haul their friends around in their cars :D
    • benime wrote:

      Some people don't want kids, some people can't have kids, and some people don't want to haul their friends around in their cars :D
      Yes of course and I'm perfectly fine with that. I just meant the no back seats statement was actually more a way of life than a love for a specific type of cars.
      Honestly, to me, outside of super/hyper cars there's nothing worth driving with no back seats. :D
      Looking for:
      - faulty Hang-On, Space Harrier or Enduro Racer (2203 sound board)
      - Sega Mega-CD 1 power board
      - Super Nintendo CPU (3 needed)



      "I'd 1cc games but I have a real life."
      01010011 01000101 01000011 01010010 01000101 01010100 00100000 01001101 01000101 01001110 01010101 00100000 01000111 01010101 01011001