Shinobi trouble

[petieken]

Maybe one of the tech guys here can help me with my Sega System 16A Shinobi pcb. When I first plugged it in through my System16 to Jamma converter I got nothing. After fiddling with the connectors I got scrambled blocks all over the screen. A reboot didn't solve anything.
I decided to remove, clean and reseat all removable ic's. Now when I power up the game I get nothing for about 1~2 minutes then the game boots normal and everything works, occasionally the screen jumps for a fraction of a second.

Is there anyone who knows where I should be looking to solve the problem?

Kev

[DarthNuno]

Now when I power up the game I get nothing for about 1~2 minutes then the game boots normal and everything works, occasionally the screen jumps for a fraction of a second.

Looks like a power supply problem. It gives too low voltage. I got a similar problem with my After Burner. The 5V given by the power supply was a little bit too low, and I just have to turn the 5V pot to adjust the voltage, and my problem was solved 
It's maybe a similar problem ?

[petieken]

Ok, I'll check the voltage. It's really weird, I powered it up again today and after about 2 minutes I get the game on screen but it looks like the sync doesn't lock so it jumps vertically and after 2 more minutes the picture is steady.

Tomorrow I'll check the voltage first

[petieken]

I measured the voltage at the board input (connector) and it reads 5.03V. I also measured at the processor, ram & eprom and all read 4.92V so you're probably right Bruno , my voltage is way to low. My current supply is fixed, so I can't regulate it to give my board a little more juice. My order at Japandeal includes a new power supply, so I have to wait a few days for that power supply to arrive.

[italiandoh]

I measured the voltage at the board input (connector) and it reads 5.03V. I also measured at the processor, ram & eprom and all read 4.92V so you're probably right Bruno , my voltage is way to low.

No, your power supply is just fine, replacing it with another one won't fix this behavior.
Seems like a bad capacitor issue, check all electrolytic caps on your board. especially in the video and reset section circuitries.

Matteo