Konami Vendetta bad c16?

[ack]

D1 line is also connected to the logic related to button input from the jamma edge connector. On my board that includes

74LS257 PIN 7 @ 11C
74LS253 PIN 9 @ 9A

Maybe one of those has a fault or is stuck enabled and is pulling D1 low. Mine are fujitsu branded which are known for failures.

 

[r67055]

D1 line is also connected to the logic related to button input from the jamma edge connector. On my board that includes

74LS257 PIN 7 @ 11C
74LS253 PIN 9 @ 9A

Maybe one of those has a fault or is stuck enabled and is pulling D1 low. Mine are fujitsu branded which are known for failures.

 

[ack]

nice! what was the fix?

 

[r67055]

D1 line is also connected to the logic related to button input from the jamma edge connector. On my board that includes

74LS257 PIN 7 @ 11C
74LS253 PIN 9 @ 9A

Maybe one of those has a fault or is stuck enabled and is pulling D1 low. Mine are fujitsu branded which are known for failures.

Thank you very much for your help. I didn't think this would start. I put the original eprom back in and when I ran the test it said the eprom was faulty.??? how can that be because I read it before the repair and it was fine. how did it go bad? well unfortunately I only have 1 eprom so I'll use the test eprom and write the contents I read at the beginning. I'll be curious to see if everything starts

 

[r67055]

nice! what was the fix?

The 253 IC had no label because it was worn out, so I pinched the 9 pins and turned it on. It was clear that it was the culprit.

 

[ack]

Thank you very much for your help. I didn't think this would start. I put the original eprom back in and when I ran the test it said the eprom was faulty.??? how can that be because I read it before the repair and it was fine. how did it go bad? well unfortunately I only have 1 eprom so I'll use the test eprom and write the contents I read at the beginning. I'll be curious to see if everything starts

Most common reason that happens to me is accidentally installing the eprom backwards, which can kill it

 

[r67055]

I am grateful for your help. Can I count on you for another pcb repair? I am amazed by the success of this repair. I have a gun smoke capcom pcbm that I would like to repair.

 

[r67055]

View: https://youtu.be/Vyb8-FRVFi4?si=rEEIIalWci4_OhPT

 

[ack]

No problem. I can try and give basic trouble shooting help, but I don't own a gun smoke board or have any experience working on one.

Based on your video I would check if the CPU is still running. Its possible something on the lower board is trashing the CPU address or data base causing the CPU to crash.

 

[r67055]

No problem. I can try and give basic trouble shooting help, but I don't own a gun smoke board or have any experience working on one.

Based on your video I would check if the CPU is still running. Its possible something on the lower board is trashing the CPU address or data base causing the CPU to crash.

thank you for your support. that's enough for today

 

[r67055]

No problem. I can try and give basic trouble shooting help, but I don't own a gun smoke board or have any experience working on one.

Based on your video I would check if the CPU is still running. Its possible something on the lower board is trashing the CPU address or data base causing the CPU to crash.

Happy New Year. I'm back. I started measuring to make sure there's no short circuit somewhere. The board draws 5V 4.5A. The top one draws 1.96A. The bottom one draws 2.5A. Could it be that the bottom one draws a little too much current? The processors are all on top.

 

[r67055]

Happy New Year. I'm back. I started measuring to make sure there's no short circuit somewhere. The board draws 5V 4.5A. The top one draws 1.96A. The bottom one draws 2.5A. Could it be that the bottom one draws a little too much current? The processors are all on top.

60Celsius

 

[r67055]

I tried to measure it, the hottest part is the prom 60Celsius degrees so I don't suspect a short circuit. Which one is the cpu on this pcb? The 10k or the custom ic under 14k?

 

[ack]

PROMs and PALs can get pretty warm.

I don't own the board, but mame suggests there are 2x Z80 CPUs. One is for the main game code and one for audio. Looking at board pictures online, I would assume D780C @ 10K is the main Z80.

 

[r67055]

No problem. I can try and give basic trouble shooting help, but I don't own a gun smoke board or have any experience working on one.

Based on your video I would check if the CPU is still running. Its possible something on the lower board is trashing the CPU address or data base causing the CPU to crash.

I started to measure. Two pcbs are connected. Clock pin6 is going. Pin26 is not in reset, high. Pin 18 is HALT high. 27 pin pulse. A10-A5 (pin40-35) is puse. Pin30-34 is active low. Pin 2-5 is active high. Pin 7-10 is active low. Pin 12-15 is active low. I experience these on the D780C CPU pins. When the CPU is running, most of the data lines are not working.

 

[r67055]

I started to measure. Two pcbs are connected. Clock pin6 is going. Pin26 is not in reset, high. Pin 18 is HALT high. 27 pin pulse. A10-A5 (pin40-35) is puse. Pin30-34 is active low. Pin 2-5 is active high. Pin 7-10 is active low. Pin 12-15 is active low. I experience these on the D780C CPU pins. When the CPU is running, most of the data lines are not working.

The B pcb (bottom) has 4 ls245 next to each other, 3 of them have 19 pins low. And one of them is pulsing. I'll start from there and I need to find out why.

 

[r67055]

I haven't found any suspicious reason that could cause the error. Should I approach it from a different direction?