Hi all,
Recently got hold of a original ladybug pcb from ebay as faulty and here it is out of its bubble wrap.The pcbs look all complete but very dirty
.
Now lets plug it in to the test rig and see what happens.
Well the good news is that there is video sync,rgb and a constant audio tone but the game is not booting.scoped around the z80 cpu and the reset pin is going high,clock is present,data and address bus are either high or low and the halt pin is low .This appears to me that the cpu is in a crashed state😖 ,now the next step i took was to give the cpu(top) and video(bottom)pcbs a clean.
now that they are cleaned i removed all ic sockets and electrolytic capacitors and fitted with new ones.
ok the next step was to check all the eproms,proms and the z80cpu which i removed before cleaning the pcbs,there are 6 cpu roms and 2 graphic roms on the top pcb.All 8 roms verified as ok using romident and the z80 cpu was checked inserting it in my pacman midway pcb which booted ok.The bottom video pcb has 2 grx roms and 3 colour proms which all checked out ok using romident except 1 grx rom at 7H did not match,this was erased and reprogrammed with correct code.There are 8 work rams(2114) and 2 sprite rams(2114) which i wanted to test but they were soldered in 😖.Took the decision to remove all the srams and put new sockets in,fitted one at a time to my pacman midway pcb and 7 work rams failed and 1 sprite ram failed.As nearly all have failed i fitted in new ones to there sockets.
To be continued............................................🐞
Recently got hold of a original ladybug pcb from ebay as faulty and here it is out of its bubble wrap.The pcbs look all complete but very dirty
.Now lets plug it in to the test rig and see what happens.
Well the good news is that there is video sync,rgb and a constant audio tone but the game is not booting.scoped around the z80 cpu and the reset pin is going high,clock is present,data and address bus are either high or low and the halt pin is low .This appears to me that the cpu is in a crashed state😖 ,now the next step i took was to give the cpu(top) and video(bottom)pcbs a clean. now that they are cleaned i removed all ic sockets and electrolytic capacitors and fitted with new ones.
ok the next step was to check all the eproms,proms and the z80cpu which i removed before cleaning the pcbs,there are 6 cpu roms and 2 graphic roms on the top pcb.All 8 roms verified as ok using romident and the z80 cpu was checked inserting it in my pacman midway pcb which booted ok.The bottom video pcb has 2 grx roms and 3 colour proms which all checked out ok using romident except 1 grx rom at 7H did not match,this was erased and reprogrammed with correct code.There are 8 work rams(2114) and 2 sprite rams(2114) which i wanted to test but they were soldered in 😖.Took the decision to remove all the srams and put new sockets in,fitted one at a time to my pacman midway pcb and 7 work rams failed and 1 sprite ram failed.As nearly all have failed i fitted in new ones to there sockets. To be continued............................................🐞