Jr. Pac-Man displaying garbled screen and no sound when turned on

[myntric]

I picked up this cabinet last weekend and after a careful cleaning and doing an initial look over, I turned it on and the display was beautiful but shows garbled images and there's no sound.  The test switch and credit button doesn't seem to do anything either so I'm not sure if it's a power issue,  wiring harness issues, or what.

I'm pretty new at this, but so far I've checked the ROMs/EEPROM's to make sure they are seated and was not able to find any visible loose chips, wires or bad solder points anywhere.  My next step is to pickup a multimeter and make sure there's no glaring power issues anywhere but am curious if anyone has had any experience with similar issues and can point me in the right direction.

Below are a couple of pics I took of the issue.

http://www.reversemalware.com/arcade_images/20160225_214207004_iOS.jpg
http://www.reversemalware.com/arcade_images/20160225_214536245_iOS.jpg

Thanks!

Mike

[P-feif]

Step one check you voltages. If they aren't right the board won't work correctly. On Pacman and Ms. Pacman the power supply is built into the board. I don't know how it works on Jr. Pacman, but start with checking your voltages.

[myntric]

Power is on the board with Jr. Pac-Man as well.  Tested power from cord, through fuses and to the pcb and it all checks out.  Ironically my Ms. Pac-Man cab started displaying F's and A's across the screen today after it was working fine for the past several weeks.

[TheGuru]

you've just got a classic logic fault. it's very common to see old 80's PCBs failing with logic faults or RAM faults.
watch Adam's Repair 101 video's on CPU/logic theory and start checking logic with logic probe.
you could also start at the CPU and check you have a clock on pin 6 and reset signal (high to low transition on bootup) on the reset pin.
otherwise, you have a common logic fault....

[John's Arcade]

Did you check the line voltage only? Don't check that. Check the +5V and 12V on the PCB.

It could be a simple issue you have there. I have fixed boards like that by reseating the ROMs. Did you just inspect them or did you actually pull them out, inspect them, clean as needed, and resocket?