PCB Reproduction: Space Harrier/Outrun Deluxe Motor Drive
I thought I’d plug the PCB we’ve been working on over at UKVAC.
It’s an open-source Circuit Maker project where we took the hard-to-find motor drive PCB for Outrun and Space Harrier Deluxe and made our own.
Engineering-wise, we had the original schematics to follow and, fortunately, we also had access to a PCB to work out the unreadable bits.
A dump of the two 153 PALs was also obtained (thanks Retroclinic).
A bit of an art project really, as we tried to match the original functionality and routing as closely as possible. Where components are obsolete, it’s dual-pinned (e.g. those are 22V10 GALs I’ve translated the 153 code to).
An interesting PCB. It drives 1 or 2 DC motors from an 80V ac mains supply by synchronising to the mains and enabling the triacs at the appropriate points of the positive or negative mains-cycle. All control is via 74LS logic and the PALs – the game PCB simply send a pair of 4-bit speed commands (where 0x8 is stationary).
So far it seems to work well in the cabinet it was tested in (and lots of bench testing was done by me beforehand as I haven’t got a cabinet), so a couple more prototype tests and it should be good to do.
I’ll not go to too much technical detail here as it’s all on UKVAC (log-in to see the Arcade Homebrew page where we try to work it all out, including the triac circuit and even a video), but if you know anyone who needs a board then follow the link above.
Note that it’s cheap as it’s non-profit and non-commercial, so no-warranty is offered.
I’m (JB) also happy to try and help with questions on fixing old motor drive PCBs.
Not Phil