I picked up a non-working Laser War a few months ago, with heavy battery damage to the original MPU board. Not wanting to invest too much time on a basically hopeless board, I picked up an allegedly working rev 3 MPU off of Ebay (pulled from a LW3).
As you may know, a rev 3 MPU board will not work directly in Laser War, for a few reasons (27C256 ROM vs 27C512; extra pins on C12, etc.). Anyway, I'm currently running through the "conversion" process laid out by an old DE service bulletin but am not having any luck getting fully through the boot process--or so it seems.
Basically what I'm seeing is that the board goes through the basic self check portion of the boot successfully (+5/PIA flash to Blank/+5 solid) but then basically nothing happens (nothing on the display, no sounds, no controlled lights, etc.)...However, I can see ghosting in some inserts if, e.g., I hit the coin switches, start button, etc., so it seems like *some* software might be running???
I verified that my installed EPROM is valid (matches V1 ROMs on Stern's site)...
Set jumpers using info from the following:
Set on: J4 (32KB ROM), J5A (no clue), J6A (single ROM?)
Set off: J5 (64KB ROM), J5B (no clue), J6B (dual ROMs?)
The pinwiki guide said to set J7A instead of J7B, but I skipped that setting as my original Laser War MPU had J7B set. I have no idea what J7x controls, however...
Surely I've screwed something up here...Anyone have any ideas?