Bootleg PCB King of dragons GAL20V8

[Kernel32]

Hello
I have a bootleg PCB with the game King of Dragons (from CAPCOM)

The board is considered dead, blue screen with waves.
I did some tests and i found continuity between ground and VCC, I found the faulty chip, it's a GAL20V8 shorted between ROMs 3 and 4 (on this board I have 1 GAL20V8 near the CPU, and 2 GAL16V8 near maskroms)
So my question, where can I find the program to load inside the GAL20V8 ?
My board seems to be the same like "Cadillacs and Dinosaurs" = http://www.jammarcade.net/pal-dumps/Do you think is it a good idea to load this .JED : http://www.jammarcade.net/files/pals/Ca ... 0v8a-1.jed" to test if I have a boot ?

I tried to read and backup the 2 GAL16V8 but I can't read with my EPROM programmer Minipro 866, I think they are locked ...

Have a nice day and Thank you.

PS : I found the short with a multimeter / continuity test, the first test to do before power on, and to find the faulty chip I power on and put fingers on the board, I detected 2 very hot chip, and one of those was Dead.

[porchio]

Generally PLDs run quite hot.
Where was the short on the chip?
Something else to keep in mind, just because the continuity tester beeps doesn't necessarily mean there is a short. What was the resistance?

I recall on my Silent Scope boards the resistance between VCC and GND was about 16ohms so the continuity tester did beep even though the circuit was fine.

[caius]

I have this board but sadly I can't dump the locked GAL20V8A since it's 24 PIN PLD.I think you can't use the PLD from Cadillacs & Dinosaurs even if PCB layout is the same but memory map is different.

[Kernel32]

Hi,
@ porchy : the short is between the ground and the VCC pin, I have continuity, I will check this evening the resistance ... (but i also checked on my programmer and I can't do the test due to the short)

@ caius : Ok thank you, I will try to find a way to repair this board ...

Have a nice day

[Kernel32]

Generally PLDs run quite hot.
Where was the short on the chip?
Something else to keep in mind, just because the continuity tester beeps doesn't necessarily mean there is a short. What was the resistance?

I recall on my Silent Scope boards the resistance between VCC and GND was about 16ohms so the continuity tester did beep even though the circuit was fine.

I checked the resistance it's 15,6ohms.

[caius]

Did you test the resistance betwenn GND and VCC of the GAL desoldered from PCB or still soldered?

[Kernel32]

No I tried desoldered because the board is shorted.
Without the GAL I don't have continuity between GND and VCC on JAMMA connector.
If you want I can solder the PAL on the board to test the resistance if it's necessary.

[Kernel32]

Hello
I programed a new GAL20V8 with the first set of "Cadillac and Dinosaurs" and now I have always a blue screen (but without waves) and I have sound, so It's a good begining
I checked the 68000 CPU I have pulse and reset pin HIGH but no activity on adress data pins.
I verified every ROM and MASKROMS they are OK.

Sometimes when I boot the game I have a strange screen with some 00 and & etc ...

I tried to program other GAL20V8 from the game "Cadillac and Dinosaurs" but only the first set give me something = the sound

I received the logic comparator I will check logic TTL ..

[Kernel32]

Hello
the board is in watchdog mode, I'm looking for the bad TTL ...