Picked this up for a very reasonable £25.
Already have a working pengo boot but thought this would be a fun little fix.
Two missing 6116 ram (ringed in red) which I had spares for.
Booted to a blank screen,CPU showed clock and reset but no sync signal I could see.
Looks like it's similar to the original where a couple of LS161 chips are part of the sync generation circuit.
Looked at one and it was showing no activity on it's outputs but slicing it showed it be be OK.
Did notice pin 10 was constantly low which stops it from counting and that came from the LS161 circled in blue.
This LS161 turned out to be faulty and replacing it brought garbled graphics.
I next checked the CPU roms and rom 2 had a broken leg.
Repaired that and it booted into the game,all graphics and sprites are good.
Just sound and inputs to test now.
Already have a working pengo boot but thought this would be a fun little fix.
Two missing 6116 ram (ringed in red) which I had spares for.
Booted to a blank screen,CPU showed clock and reset but no sync signal I could see.
Looks like it's similar to the original where a couple of LS161 chips are part of the sync generation circuit.
Looked at one and it was showing no activity on it's outputs but slicing it showed it be be OK.
Did notice pin 10 was constantly low which stops it from counting and that came from the LS161 circled in blue.
This LS161 turned out to be faulty and replacing it brought garbled graphics.
I next checked the CPU roms and rom 2 had a broken leg.
Repaired that and it booted into the game,all graphics and sprites are good.
Just sound and inputs to test now.
,just of interest what make was that faulty LS161?
