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Zaccaria Jackrabbit Maintenance 2023

01/06/2023 - Northwest Pinball and Arcade Show (2023)

Zaccaria games at the Northwest Pinball and Arcade Show Zaccaria games at the Northwest Pinball and Arcade Show
Jackrabbit rolling picture

On show day 1 the monitor suffered partial vertical collapse and vertical roll. The spare MTC-900E/USA chassis was swapped in, and the game ran without issue for the remainder of the show.

07/28/2023 - Hantarex MTC-900E/USA chassis PA20180629 repair, part 1

Hantarex MTC-900E/USA chassis on the bench MTC-900E/USA sync input transistors

This was the second year that this chassis had developed vertical collapse and roll at the show. I concluded that this was something that occurred when the chassis was on for several hours. On the bench the chassis was running with no issues. None of the adjustment pots appeared to have instability and neither IC2 or IC3 had any effect when pressed on, ruling out an obvious bad socket. Other chassis had sync issues as a result of BC237 failure in the sync input circuit so T1 to T4 (BC237) were all replaced. None of the ones pulled tested bad by either back-to-back diode or Hfe test. The chassis was set aside for retest in the cabinet.

08/03/2023 - Hantarex MTC-900E/USA chassis PA20180629 repair, part 2

MTC-900E/USA vertical shift pot

I'd recently encountered a sync lock issue on a MTC-900E that was caused by a failed adjustment pot and decided to measure the tracks of all the adjustment pots in circuit:

The track resistance should have been less than the stated value in all cases but RV23 (1K), vertical shift, measured 9.2K. The pot was removed and out of circuit the track was open and open one side to the wiper. The remaining track-wiper resistance measured 352 Ohms. A replacement PIHER 1K 15mm pot was preset on the bench to 352 Ohms and fitted into the chassis.

03/04/2024 - Pre-show testing

Jackrabbit with test pattern generator MTC-900E/USA test pattern display Zaccaria Jackrabbit display

Pre-show testing found the game with no display playing blind. I'd seen blanking problems before on both the game PCB and monitor chassis so the first step was to connect a test pattern generator to confirm a monitor or game PCB problem. The test pattern displayed OK. After reconnecting the game PCB, video was working, and the game played OK. A couple of days of additional multi-hour testing didn't encounter any issues and the game was declared working.



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