Got this bootleg board for a repair.
The game could be played with music and sound but had a problem on the text layer:
I started probing around until by shorting carefully pins of some TTLs I found the circuit of the text layer on the upper board.
A 74LS86@5J had all its output in the grey area (2.2V):
Changing it with a new one solved completely the issue:
We had two separate files for M92-b-2l.
One was just labelled for M92 hardware and the other was for Ninja Baseball Batman.
I deleted the entry for M92 as the Ninja Baseball Batman dump was from an actual unlocked PAL chip.
End user will not notice any difference, this update is to keep a record of what has been done and when.
I got an M92 PCB here that uses MASKROM’s from SHARP.
These MASK’s in particular are pin compatible for either 27C020, 27C040 or 27C080 EPROM’s.
It is possible to determine which to dump these as from the markings on the chip. They all begin with the ID LH53#, where # is the identifier of the size.
“LH532” = 27C020 dump
“LH534” = 27C040 dump
“LH538” = 27C080 dump
The remaining letters/numbers of the markings are unique to the game and location on the PCB.
Sometimes it is very annoying when you have placed your arcade monitor vertically and certain games are shown upside down and even worse they have no option to flip the screen.
It happens very often with older games but sometimes even with newer games from the 90s.
In these cases you have 2 options: reverse phisically your monitor or reverse the yoke on the pcb of the monitor (not very safe).
Now I show you a new option available only when the games were also prepared for cocktail tables (that means they have already the circuit to flip the screen for the second player)
In this first “flip screen” hack I will take Zaxxon / Future Spy hardware as an example
These games have no flip screen option but they have the preparation for cocktail tables play.
The board is very big but luckily schematics are available and they are very clear to understand.
The hack is very simple: input nr.4 of 74ls367@U64 is normally LOW for first player game and HI for second player game.
We have only to force pin 4 to HI (+5V) using a wire so that the screen is always flipped as it was playing the second player even in upright mode.
Very simple and effective!
Ace’ has tested the Bay Route (317-0116) decrypted set and report it works fine.
Thanks to Ace’