Galaga PCB error..

Cyberflexx · Post by **Cyberflexx** » Fri Oct 31, 2008 7:09 am

Since Ben was kind enough to help me with the power supply issue on my NeoGeo a couple years ago, I thought I would ask for some help with my Galaga PCB.

Here is the error I am getting along with a high pitched squeal when I 1st turn the machine on. I dont get the scramble colors / letters and the grid video test screen at all and I dont hear the 'boom' sound it is suppose to make when its finished booting up.

What I have dont is checked the voltage to the board, it is at +5 volts. I swapped around the 2 Z80 processors in hopes of getting an error code. I have pulled the IC's off and cleaned the legs. I have ordered another galaga PCB that was missing the IC's and used the video board with the IC's from the original PCB and I still get the same error.
I have not had time to swap out the CPU PCB with the other one that I have.

I have read around the net and asked questions on other forums and no one has ever seen this error before.
Anyone got any other thoughts?

Thanks!

Cyberflexx · Post by **Cyberflexx** » Fri Oct 31, 2008 11:12 pm

IT'S ALIVE!!!!!!!!

Well, I was able to play Galaga tonight. I fixed it. Board level repair and a bit of luck.
I ordered a galaga PCB from a guy on ebay for 16 bucks that had missing parts to it. 1st thing I did was swap out the video board and all the IC's. Plugged it in and same results as before. Tonight I did the same thing but with the CPU board. In the process I accidentally broke a pin on the 53xx chip @ 4h posistion on the board. I had to take a jumper wire and tack it to the back side of the socket and solder it to the very very small section of broken pin on the processor.

Every once in a while the screen will flicker very quickly, so i might have a loose wire somewhere or my monitor is slowly drifting away. The red color needs adjusted some, but other than that, I am very happy!