cps1.5 cadillacs and dinosaurs stuck on stage 6 "illegal inst. 0008A4BE" error

[roy]

hey guys
the gameplay get stuck on stage 6 on the same place with this error
B board running on battery
C board has no battery mod, 2 wires connected from the C board chip to the B board (im clueless of what it is...)
thanks all

 

[xodaraP]

Verify your main program ROMs, one is likely faulty.

 

[roy]

what do you mean verify? how

 

[xodaraP]

Take the main program ROMs off the board and use a programmer to verify them against the MAME set

 

[roy]

ok
i dont have that option...
i wonder if it got something to do with the batteryless mode of the c board

 

[xodaraP]

Well it does in so far as you need to replace or reprogram the main program ROMs. If whoever did the mod hasn't burnt them correctly or one of the chips is bad, it will crash.

You need a programmer or someone with a programmer to test them for you.

 

[roy]

sorry for not asying-all roms are stock
nothing has been touched other then the c board

 

[djsheep]

@roy that doesn't mean that over time the chips data won't get corrupt.

It's PCB Repair 101, dump and compare the chips

 

[roy]

i understand but unable to do this
ill try using the roms from my other c and d but it will be stupid that way...

 

[xodaraP]

If the C board has been modified to run without battery, the main program ROMs are no longer stock.

The stock ROMs are encrypted and can only be decrypted with the keys stored on the C board with a battery.

If they look stock it's because they have been rewritten and the sticker carefully reapplied.

Original or decrypted, as @djsheep said they can fail over time.

 

[roy]

any chance the 2 wires are connected from c board battery pins to the b board battery in parallel?

 

[xodaraP]

No. They're connected to the +5 - it's a no battery mod

The B board battery is 3.6v and the C board battery is 3v