The first few steps of any project are always the longest and the hardest. ...
After you get past that, you'll look back and laugh with the power of hindsight. :)
Neat project.
You should make a Spinner Refresh kit--for all those original spinners out there that need to replace broken gears and worn out soft plastic bushings.
And, also repro the Puzz Loop Jamma-Spinner PCB to go with this.
Remove the OEM key.
Get a multi-kit pic chip. Install it.
Boot the board. Enter the test menu, and change the region.
Save, exit, and power down.
Remove the multi-key, and re-install the OEM key.
=)
Yeah, I think I noticed a calibration issue too last time I messed around with it (Rambo or GSE????). BUt it's been a while. Perhaps someone else can confirm.
The PIC dumps are in mame.
https://github.com/mamedev/mame/blob/master/src/mame/drivers/lindbergh.cpp
https://git.redump.net/mame/diff/src/mame/drivers/lindbergh.c?id=7a0537104e8f03ae23a66c4946fab7f1c6ecb11e
They've been there for a while now.
Not sure why this topic is taboo.