Williams board issue? SEE PIC

kjoel

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Popped this board set into my stargate and also my robotron and it did this in both units. Is this a decoder ram issue? Never seen this before

Any ideas :confused:
 

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Ok, I'm going to guess: Is the "board" the CPU board? ROM Board? etc?

If the same board works in neither Stargate or Robotron, check several things like:

a) battery corrosion
b) it's not a Williams CPU that's not compatible with those games
c) bad crystal
d) low +5 to the chips
e) bad processor
f) bad ribbon cables between the boards
g) bad decoders

etc...
 
My Defender boards were doing something like that when I picked them up. I've fixed them enough to run the rug pattern, but I've slacked off since then.. I really need to get back to them speaking of which..

ANYWHO... there are some good Williams flowcharts out there if you have a logic probe and/or o-scope?
 
I've seen that twice. One time swapping the CPU worked. Another time swapping out the address decoder chips (74153) has at least brought it to the next level of issues.

ken
 
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I've seen that twice. One time swapping the CPU worked. Another time swapping out the address decoder chips (74153) has at least brought it to the next level of issues.

ken

I'm with YellowDog... That is a symptom of a bad CPU, socket, or someting stopping the CPU from running. There was a thread with the same symptoms about a year ago.

Mike
 
Sorry its the cpu board. its not the ribbon cable as I tossed this cpu board into 2 fully working cabs. I have plenty of board sets around the house to strip off a few chips. No battery corrosion on the board either. I will try the cpu and then I will have to purchase the decoder roms. We'll see how it goes !

Thanks guys
 
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