You could say I've had this board quite a while. It came in a job lot from this listing in February 2016 by Alpha1.
http://www.ukvac.com/forum/job-lots-of-arcade-pcbs_topic350246.html
I took photos of the board when I got it but I can't find them (it was 4 years ago) - the board was shocking (described as wet/pooped) and I'm sure Oliver can verify that. I decided whether to keep the board for spares or to rebuild it - I decided to rebuild it.
Numerous parts were replaced in the corroded area - possibly 20% of the populated PCB. Although the affected chips were very bad the underlying PCB wasn't so bad.
SK1-2 was also dead so I borrowed one from my working board along with CUS 38. After rebuilding the board I powered it on and the board would freeze and it stayed that way for a number of years.
I then decided to have another attempt to repair it - I had a breakthrough moment a few months ago and replaced an IC chip (which I sadly can't remember) and the board booted fine but with corruption to the backgrounds.
There are no schematics for the board so it complicated things greatly. I kept returning to the PCB trying to find a fault but couldn't (concentrating on logic chips mainly). However, today I decided to map CUS 38 and compare it against my worker. The pinouts are below (D - dead, L - logic, H- high, G - ground).
Pin 45 was dead and all other pins seemed to be ok. So I traced pin 45 on my worker and it went to 10C a TMM2016BP RAM chip and 9D a 74ls174. I had no continuity on the faulty board. So I tracked down the break in the trace - it went beneath the crystal clock. There was slight amount of corrosion from the crystal through hole that had spread to the trace, very close to it. I patched in a wire trace underneath the crystal over the broken trace.
And Sky Kid lives again - it's such a great game I had to repair it, even if it has been sat on the repair pile for nearly four years.
http://www.ukvac.com/forum/job-lots-of-arcade-pcbs_topic350246.html
I took photos of the board when I got it but I can't find them (it was 4 years ago) - the board was shocking (described as wet/pooped) and I'm sure Oliver can verify that. I decided whether to keep the board for spares or to rebuild it - I decided to rebuild it.
Numerous parts were replaced in the corroded area - possibly 20% of the populated PCB. Although the affected chips were very bad the underlying PCB wasn't so bad.
SK1-2 was also dead so I borrowed one from my working board along with CUS 38. After rebuilding the board I powered it on and the board would freeze and it stayed that way for a number of years.
I then decided to have another attempt to repair it - I had a breakthrough moment a few months ago and replaced an IC chip (which I sadly can't remember) and the board booted fine but with corruption to the backgrounds.
There are no schematics for the board so it complicated things greatly. I kept returning to the PCB trying to find a fault but couldn't (concentrating on logic chips mainly). However, today I decided to map CUS 38 and compare it against my worker. The pinouts are below (D - dead, L - logic, H- high, G - ground).
Pin 45 was dead and all other pins seemed to be ok. So I traced pin 45 on my worker and it went to 10C a TMM2016BP RAM chip and 9D a 74ls174. I had no continuity on the faulty board. So I tracked down the break in the trace - it went beneath the crystal clock. There was slight amount of corrosion from the crystal through hole that had spread to the trace, very close to it. I patched in a wire trace underneath the crystal over the broken trace.
And Sky Kid lives again - it's such a great game I had to repair it, even if it has been sat on the repair pile for nearly four years.
