also having an issue with a 327-1 and the current schematics don't match & rom/code (327-4) does not work on the early series boards ... ask me how i know

board will pass the leons self test running the -4 code, but thats about it

a follow up here, was finally able to repair this non-working 327-1 mpu, i believe the current schematics may be drawn with a couple errors related to the dips - maybe, and better yet, the latest 327-4 code does indeed work with the older boards so thats a positive

just about every i/c that has an "hct" on it was blown/bad

and was able to find the 74HCT9114 at K's arcade (yes, mine was blown and part of the problem)

so, replaced the crystal, ram, rom, and about 8 gates, all of the 6821 & mpu were OK, don't know what happened to this board but whatever it was, it wasn't good

well, it actually almost a pleasure to work on a board that doesn't have acid damage or an interconnect

so, I got to a point where the board passed the leons self test but when in game mode the two leds just locked on, that's is where I began to suspect the program was the problem - I spoke to Jim at RD and he stated it should be fine with their -BD code.

problem turned out to be the 9114, replaced it and then got the normal short single flash from the two leds indicating the game code was running

I then discovered that the 74hct154 multiplexer was also blown - nothing on displays is a good clue of its demise, and logic probe agreed, replaced it with a 74154 and all is good

the feedback I have read concerning the HCT series indicates it is quite fragile