Ropeman

[favouredson]

I had another play and the static garbage no longer appears, I get VRAM OUT instead.
First pic is with Konami ROM1 and either Konami6 & bootleg7 or bootleg6 and Konami7.
Second pic is with Konami ROM1 and either both Konami6&7 or both bootleg6&7.
Third pic is with my edited bootleg ROM1 and both Konami6&7.
(I couldn't get the timing right on this one but the lines appear over the whole area which gets blacked out between screens.)


The only combination which runs with correct title screen, Konami copyright and no graphical issues is: my edited bootleg ROM1, bootleg ROM6 & Konami ROM7.

 

[Lurch666]

I must have an edited rom1 as well since I get the full konami copyright.

 

[NivagSwerdna]

Sounds interesting. There must be a hardware difference between the real thing and the bootleg. The code appears pretty simple... The first check fills the 4700 area with an incrementing pattern and checks it and the second fills 4800 with a pseudorandom sequence and then checks it. Maybe the bootleg doesn't cope with the interaction with video and CPU as well as the original?

 

[favouredson]

I must have an edited rom1 as well since I get the full konami copyright.

O your board the ROM labels are different for 1, 6 & 7. They may have been changed at some point.