Stargate Not Booting

[scottnds]

Hi
I need some help with my Stargate.It has been working OK after I changed optos and have not turned it on for a week.
Now it wont boot up and I get the screen full of random numbers and symbols and some non English words and a constant beeping.
I have been searching around on the net and found that the Pot on the power supply board sometimes will play up.So I have tested and have 5.05 volts out.
Has anyone come across this before?
There was also mention of replacing resistors.
Is there anything I can do or send off board for repairs.
Thanks
Scott.

[Steevsee]

Try reseating all ribbon connectors. Do this with Power OFF!

Also check battery voltage on CPU. (Check pinwiki if unsure how.)

[Strangeways]

Top PCB LHS is the Video board. There's a socketed Chip (PAL / GAL) - gently re seat. These go bad then the game won't boot.

[scottnds]

Thanks for the help much appreciated.
I have changed the battery and checked the chip and ribbon cables and got "control board check U3 or U6" I then turned it off and then on again and it has booted up.
I have factory defaults but I am back in bussiness.
Thanks again all.