Galaxian game Board Issue

starfighter2

Member
Joined
Sep 22, 2009
Messages
657
Reaction score
8
Location
Derry, New Hampshire
I have a galaxian board where the screen is filled with changing garbage and then it indicates "bad ram 3" real fast then starts the same cycle all over.

I was going to just get the 2 new ram chips(2101) but thougth that I should at least ask becuase of the iteration loop cycle that is happening. If it was just bad ram I would think the screen would just stay on the Bad ram screen.

Anyone see this before, please let me know your thoughts and idea of what could fix this.
Thanks
 
This seems to happen no matter if I'm in test mode or not. This is why I'm asking, it seems strange that it does not stop at the the bad ram test. Almost like a watchdog reset type of issue.I did see there where some other chips that may be causing this issue from the troubleshooting guide and have ordered both the ram and a couple of 74Ls chips. But wanted to see if anyone else experiance this type of issue before.
 
If the ROM chips are the old PROM type (not EPROM with the window) with the tarnished legs then clean the legs (inside & outside surfaces) and reinsert them in their sockets.

You may have some broken legs on them or may break some during cleaning. It happens.

But I wouldn't do that until after just replacing the RAM and seeing what happens. For those ROMs if they are working I wouldn't touch them.

RJ
 
ok so I replaced both the RAM 3 chips and the games is working with one exception. There is two of every character. One is slightly to the left and a different color. In the troubleshotting guide there are several chips that may cause distortion and one that seens to show double image - distored characters (3B - 74ls86). since this will be my third time geting parts, wanted to check to see if anyone else has had this issie and if this chip should resolve the issue.
Thanks
 
Back
Top Bottom