williams system 6 lockup

dandydan1959

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Hi Guys,
I have a williams Blackout that the MPU board is locked up. No lights no flash. I checked CPU pins and pin 31 is low and all the rest of the databus pins are pulsing. Pin 31 appears to be D2 or databus 2. I am not sure where D2 is initiated so the reason for my post. All of the address lines are pulsing. The problem started with the cpu booting up as if the cmos was not holding memory and displayed the game number in the display. I could bring the game up by toggling the power switch The next change was that occurred was a stuck on slingshot. I had checked batteries and replaced them along with making sure the voltage from the pack made it to the proper pins on the board. After making these checks the problem of no cmos memory remained. Then it went in to death mode. The 5101 is soldered in so I am going to order a couple of these and a couple of sockets. I am running the board on the test rom and on a test bench with power applied and still no flash. I assume I need to get the 5101 out and changed before I go further but if you have any suggestions let me know.
Thanks
Dan
 
Blackout mpu no flash.

Hi Bert,
As I said in my post I did check and change batteries and checked the voltage going to the board and it was good. The CMOS was still not holding memory and then when switching the game on and off the slingshot stuck on as described and then the MPU would not boot. When I power on in test setup the no numbers are displayed and the mpu does not flash. I have checked 5 volts and 12 volts and the voltages are good.

I am going to change the 5101 ram and then go from there.
thanks
dan
 
Blackout mpu no flash.

Hi Bert,
As I said in my post I did check and change batteries and checked the voltage going to the board and it was good. The CMOS was still not holding memory and then when switching the game on and off the slingshot stuck on as described and then the MPU would not boot. When I power on in test setup no numbers are displayed and the mpu does not flash. I have checked 5 volts and 12 volts and the voltages are good.

I am going to change the 5101 ram and then go from there.
thanks
dan
 
What are the logic levels of pins 9, 10, & 11 on IC10? Is D2 low on all the proms and ram and the PIA, IC18?
 
got a little further

Hi Guys,

I clipped the input of d2 on the pia and the signal returned to normal. Soldered a new socket in and place new pia in and we are good to go.

Thanks
Dan
 
awesome, thanks for the update, as the blackout i just bought acts very similar to yours was, but mine has alot of acid damage i will need to fix first
 
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