Taito Asuka and Asuka Repair [In progress]

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    • Taito Asuka and Asuka Repair [In progress]

      Hi all,
      I have a Taito Aska & Aska that boots to a garbage screen and no further.

      The RGB0070 is loose but not yet broken off (Edit: it broke off when I turned the board upside down to remove an IC)

      I noticed that the RESET and HALT lines are asserted, but the reset is moving slightly. I checked the TC0220IOC (@caius has found that reset line issues are often this chip) and the RESET output on pin 8 is working. But the board is stuck in watchdog.

      Moving from the TC0220IOC the signals are sent to the CPU via a LS07. Input is correct but output appears to be wrong.

      All I'm getting is a very weak signal to the CPU for reset, but I did notice this line is pulled down by a resistor. I'm not sure why there are resistors on the output to the CPU.

      My desoldering gun isn't working correctly but next step is to remove and test the LS07 off board and replace if necessary. I also need to build and install a RGB0070 repro board.
    • @caius - can you confirm if the bad TC0220IOC gives no/stuck reset output at all from pin 8? I don't want to pull out the LS07 only to find that it's the custom after all.

      I'm getting no data movement at all. It's literally just watchdog resetting. I did notice the 68k is getting really hot, but assumed this was due to the constant resetting.