Another oldie back on the bench..
While doing some searching I found this post - https://www.ukvac.com/forum/threads/commando-sprites-have-lines-through-them-help.11535/ so I last pulled this out in 2003
Anyway much wiser and with the correct tools in hand, this PCB is covered in dust and had seen some repairs in the past, some of which may have been me before I had the tools and skill to handle this.
On first power up, the situation had gotten worse, PCB boots to a static Commando Brown Screen.. I seem to remember this may have been me with a shitty old soldering iron reflowing the ribbon connector and I could see some Solder had flowed through so I wipped out the connector cleaned it up and and now the PCB boots to the Title screen (no sounds) & without any sprites at all now.
Looked at the original repair which was a very poorly implemented re-socket of 1A & 2A (2114 RAMS) - these tested ok, but with single line strips instead of an IC socket so these were removed and replaced, now I have some sprites along the bottom of the screen.
Scematics in hand, I could see that Pins, 1 - 7 & 16-17 (1A & 2A) are i believe tied together in parralel, for signals OB2 to OB8 however there was no continuety between pins 4, I also checked the connections for pins 11 - 14 on both A1 & A2, that move onto 1E, 2D & 3D - i found that DE6 on Pin 12 of 1A was not connecting to the respective signals, although there was tone between 2D (pin3), 3D (pin3) & 1E (pin 12) so suspected broken traces for both issues from the 2114's
Quick patch cable between suitable points, and we have moving sprites & Sound working again.. (enemy's still a bit jumpy, jailbars and the Chopper is cut in half while it lands but fine when it moves off screen.
Next step to check the RAMS at 3H, 4H, 3J & 4J - 3 out of 4 tested faulty and new sockets installed and replaced with working. (starting to run out of 2114's)
Powered up PCB, jailbar effect has now gone, but enemy sprites and chopper still not 100%, suspect more issues with the wiring on 1A & 2A as the previous repair was not great.
So this one in ongoing for now, need to check all the 2114's for signal lines incase any other broken traces but think i've exhausted that side of things.. back on it tonight i think.
While doing some searching I found this post - https://www.ukvac.com/forum/threads/commando-sprites-have-lines-through-them-help.11535/ so I last pulled this out in 2003
Anyway much wiser and with the correct tools in hand, this PCB is covered in dust and had seen some repairs in the past, some of which may have been me before I had the tools and skill to handle this.
On first power up, the situation had gotten worse, PCB boots to a static Commando Brown Screen.. I seem to remember this may have been me with a shitty old soldering iron reflowing the ribbon connector and I could see some Solder had flowed through so I wipped out the connector cleaned it up and and now the PCB boots to the Title screen (no sounds) & without any sprites at all now.
Looked at the original repair which was a very poorly implemented re-socket of 1A & 2A (2114 RAMS) - these tested ok, but with single line strips instead of an IC socket so these were removed and replaced, now I have some sprites along the bottom of the screen.
Scematics in hand, I could see that Pins, 1 - 7 & 16-17 (1A & 2A) are i believe tied together in parralel, for signals OB2 to OB8 however there was no continuety between pins 4, I also checked the connections for pins 11 - 14 on both A1 & A2, that move onto 1E, 2D & 3D - i found that DE6 on Pin 12 of 1A was not connecting to the respective signals, although there was tone between 2D (pin3), 3D (pin3) & 1E (pin 12) so suspected broken traces for both issues from the 2114's
Quick patch cable between suitable points, and we have moving sprites & Sound working again.. (enemy's still a bit jumpy, jailbars and the Chopper is cut in half while it lands but fine when it moves off screen.
Next step to check the RAMS at 3H, 4H, 3J & 4J - 3 out of 4 tested faulty and new sockets installed and replaced with working. (starting to run out of 2114's)
Powered up PCB, jailbar effect has now gone, but enemy sprites and chopper still not 100%, suspect more issues with the wiring on 1A & 2A as the previous repair was not great.
So this one in ongoing for now, need to check all the 2114's for signal lines incase any other broken traces but think i've exhausted that side of things.. back on it tonight i think.
