[HELP] Irem M107-C-B board conversion to Fire Barrel

[Tailsnic Retroworks]

Hi. I hace converted successfully a World PK Soccer to Fire Barrel, but I have a freeze bug a few seconds after the music plays. I'm using the decrypted roms and I have put the two "N" jumpers.

On attract mode the game works perfectly. I know this is because M107-B-4B PAL logic is not the same.

This romboard is special because it has extra size for connecting a foot-shooting I/O board.

So, in the second photo, you can see there is a PAL16R4 socket not populated. A jumper is joinning pin 9 to pin 13. I have quit that jumper and installed the correct PAL.

According to PLD archive, this PAL logic is:

/** Inputs **/ Pin 2 = i2; Pin 3 = i3; Pin 4 = i4; Pin 5 = i5; Pin 6 = i6; Pin 7 = i7; Pin 8 = i8; Pin 9 = i9; Pin 12 = i12; Pin 18 = i18; /** Outputs **/ Pin 13 = o13; /**(Combinatorial, Output feedback output, Active high) **/ Pin 14 = o14; /**(Registered, Output feedback registered, Active high) **/ Pin 15 = o15; /**(Registered, Output feedback registered, Active high) **/ Pin 16 = o16; /**(Registered, Output feedback registered, Active high) **/ Pin 17 = o17; /**(Registered, Output feedback registered, Active low) **/ Pin 19 = o19; /**(Combinatorial, Output feedback output, Active low) **/ /** Equations **/ o13 = i8 & i9; o14.d = ; o14.oe = OE; o15.d = ; o15.oe = OE; o16.d = ; o16.oe = OE; !o17.d = !i3; o17.oe = OE; !o19 = i4 & i5 & !i6 & !i7;

I have traced, and I have many differences in this board (I think, I don't have the other romboard type so I don't know a pinout to compare).

The output signals I should be worried are o13 and o19.

o13 is i8 & i9, and in my case i8 is direclty connected to o17
o19 is i4 & i5 & !i6 & !i7, and o19 is giving CLK signal to PIN1 of the PAL.

I know for sure changes must be done in this zone, but not having the other type of romboard makes me impossible to know.

 

[Tailsnic Retroworks]

Alright, seing another romboards like Undercover Cops, that PAL16R4 socket is empty and with the same jumper, and CPU PAL is also installed apart. So World PK Soccer doesn't have implemented that PAL on the romboard. This makes sense because at main CPU level, this game is tiny.

Then I'll save this board for personal replacements and seek for a Dream Soccer '94.

 

[RepairGuy95]

Perhaps once you get 94' you can find the differences.

 

[Tailsnic Retroworks]

Perhaps once you get 94' you can find the differences.

Yeah, if anyone can help me tracing pins, we can make it public. Here are they in JALECO rom board:

PAL PIN3 to connector CN1, pin B8
PAL PIN4 to pin 76 of custom GA32
PAL PIN5 to pin 75 of custom GA32
PAL PIN6 to connector CN1, pin A9
PAL PIN7 to connector CN1, pin A12
PAL PIN9 to connector CN1, pin A14
PAL PIN13 to PIN5 of sound custom
PAL PIN17 to PIN8 of itself
PAL PIN19 to PIN1 of itself

Those are all the required pins for the logic in the PAL.

 

[Ape Cosplay]

It is possible to convert World PK Soccer to Fire Barrel without any hardware mod (outside of jumpers) but the sound code has to be altered otherwise there are some conflicts with the extra IO ports.

 

[Tailsnic Retroworks]

It is possible to convert World PK Soccer to Fire Barrel without any hardware mod (outside of jumpers) but the sound code has to be altered otherwise there are some conflicts with the extra IO ports.

So I suppose the jumper for reset signal has to be put and not installing any gal. That's why the game puts its screen in black just after the disclaimer leaving the jumper as is. When quitting the jumper and using the correct PAL, the game works perfectly on mute attract, but when playing a few seconds it freezes and reset.

What has to be altered in the hacked sound code?

 

[RepairGuy95]

Obviously altering code would be better than cutting traces.
Is cutting traces to the i/o possible too?

 

[Ape Cosplay]

That's why the game puts its screen in black just after the disclaimer leaving the jumper as is.

The black screen is due to the main CPU entering a loop waiting for the sound CPU to answer 0x80 or 0x82 (from the top of my head).
I've done the conversion before but not sure I still have the files (2 drive crashes in the last 4 years).

 

[Ape Cosplay]

Files found and sent to @Tailsnic Retroworks, confirmed working.
Before releasing them publicly I'd like to secure a World PK Soccer boardset.
Today it's NOT a good donor for conversions unless you have my files.

 

[RepairGuy95]

^ You rock.
Someone find this man a board.
(I'd also be interested if you have another)

 

[Tailsnic Retroworks]

This is the correct distribution. Zoom to see the jumpers.