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Zaccaria Cat'n Mouse Maintenance 2026

06/06/2025 - Northwest Pinball and Arcade Show (2025)

Zaccaria games at the Northwest Pinball and Arcade Show
Cat'n'Mouse with graphics issues

Saturday morning walkthrough found Cat'n'Mouse with graphics issues. A spare main game PCB was swapped in and the game ran OK through to show closing.

Due to house move & sale, significant remodeling of our destination house and retirement, the failed game PCB was forgotten until 2026...

06/06/2026 - Northwest Pinball and Arcade Show (2026)

Zaccaria games at the Northwest Pinball and Arcade Show

On Saturday night the game was reported to the medic desk with a blank screen. Investigation found the monitor on and power supplies all measuring OK. The audio board did initialize with music sometimes, but there was no response to coin or start suggesting the main PCB had failed. I had forgotten that the spare main PCB was already installed in 2025. Luckily this is the only game for which I had two spare main PCBs and the 2nd spare was swapped in that ran OK for the rest of the show.

17/06/2026 - Main PCB PA20221120 repair

Cat'n Mouse main PCB on the bench

On the bench as in the cabinet there was no video output but the scope showed composite sync was running. Checking the latch IC 10I (LS74) found:

The composite blanking signal ~CBLANK was stuck low (active). Working backwards to IC 9E (LS04) pin 5 input was idle hi and output idle lo. Moving on to IC 12B (LS00) pin 9 & 10 inputs were active but the output pin 8 was idle hi. To confirm if this was an input signal issue, I briefly shorted pins 9 & 10 together that resulted in graphics becoming visible but with a repeating pattern indicating a potential issue with the video timing.

Cat'n Mouse main PCB replacement video counters

Checking the video counters with a scope found:

I suspected IC 15D was bad, and this was the 2nd of four 8019 date code 'SA' Signetics LS161 to fail so I elected to replace IC 15D and the two remaining ICs as a preventative maintenance. After replacement the game booted and played OK.

21/06/2026 - Main PCB PA20201224 repair

Cat'n Mouse main PCB on the bench Cat'n Mouse graphics fault

The game displayed misplaced walls and the cat sprite was leaving tiles behind. The randomness of the pattern didn't suggest a simple stuck video counter so the Arduino ICT was installed that flagged "E:12F 1800 01 0f" and "E:13F 1800 90 50". Further, a "RAM Write All Lo" resulted in artifacts similar to those seen when the board first booted after power on. Several writes were needed to clear the RAM completely. RAM IC 13F had already been replaced and since the region was comprised of 2 x 4-bit RAM it seemed unlikely both would have the same fault. The data bus DD0 to DD9 looked consistent on the scope, and the write select WBG also looked OK. Moving on to the address bus and address multiplexors IC 12E,13E,13D (LS157) a quick piggyback check didn't change any behaviour. Poking around IC 8H (LS32) also didn't reveal anything obvious. Setting up the HP Comparator for LS157 and testing found:

Checking logic levels on both BA8 (IC 13D pin 2) and BA9 (IC 13D pin 3) found TTL compliant Lo @ ~0.4V and Hi @ ~3.5V. Further, the miscompare only occurred when the CPU was accessing the RAM. I suspected IC 13D was stuck selecting the video address and replacing IC 13D (LS157) enabled both the RAM test to pass and fixed the display.



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