Trying to bench test centipede boards, video output question.

Kadajett

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Hey again all! I am working on getting centipede to play nice with my Jamma test bench. I confirmed RGB wires are properly placed, and have continuity. This harness is outputting to a small control panel, and an Ikegami tm10-17ra via the RGB input. For centipede, I also passed the sync output to both the sync-ext inputs with a small jumper combining them.

This works great for Jamma boards, but I have never tried this with a custom harness.

I also don't know if this centipede works, which is why I built the test harness in the first place 😅 I have the +-5v,+-12v hooked up, but none of the higher voltages that should just be responsible for allowing saving of scores.

Right now, I am just getting flashing vertical lines that are usually yellow, but sometimes are blue and red. They don't shift horizontally, they just flash.

Any idea what I could try next?

Here is a video of it, though it looks way more consistent off-camera.

 
This is more of a centipede question than a monitor question, I think. Maybe 🤔
 
I don't think this is a sync issue. Doesn't look like game is running. However, centipede can put out composite sync and you can use the video out test point to just do composite "video" input which will be b/w.

I show how I hooked mine up and cover other sync points here.
 
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Looks like the video is hooked up correctly. I would start with the basics, like checking the voltage at the PCB. You should only need +5V to boot the board.

Check that the CPU is not being held in Rest (Pin 40 of the 6502 @ C2).
Check pin 6 (NMI, should normally be High)
Check Pint 4 (IRQ, should normally be Low)
Check your Clock input on Pin 37
Check for Activity on the Address Lines (Pins 9 - 25)
Check for Activity on the Data Bus (Pins 26 - 33)

You should also be able to put the game in Self Test and see if you get anything different.
 
I don't think this is a sync issue. Doesn't look like game is running. However, centipede can put out composite sync and you can use the video out test point to just do composite "video" input which will be b/w.

I show how I hooked mine up and cover other sync points here.
This worked super well. Was able to confirm that all 10 of these centipedes are broken in various ways lol this is gonna be a long week 🫠
 
Looks like the video is hooked up correctly. I would start with the basics, like checking the voltage at the PCB. You should only need +5V to boot the board.

Check that the CPU is not being held in Rest (Pin 40 of the 6502 @ C2).
Check pin 6 (NMI, should normally be High)
Check Pint 4 (IRQ, should normally be Low)
Check your Clock input on Pin 37
Check for Activity on the Address Lines (Pins 9 - 25)
Check for Activity on the Data Bus (Pins 26 - 33)

You should also be able to put the game in Self Test and see if you get anything different.
I will definitely start here on the ones that look close to working.
 
Out of curiosity, if you had a nice Jamma setup then why not just buy an adapter?
 

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Mostly for learning and understanding! I will buy one eventually lol
 
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