Recently purchased a faulty booty of bombjack from ALPHA on here,said there's no picture and no sound and stated the rgb header is broken. So lets try to fix it,here it is on my bench. 
Pcb looked in nice condition except for that rgb header which was a mess.
Got it replaced.
Right now to connect up the jamma adapter and fire it up,but no luck as there's no pic or sound.Scoped the main Z80cpu on the bottom pcb for activity,all looked ok with reset good and buses active........mmmmm🧐.Decided to have a closer look at both pcbs for anything odd until I found 3 broken traces on the video board(bottom),looks like a deep scratch.
Fixed the 3 broken traces with kynar wire and fired it up and good news we have a picture but failing to boot showing error ram 0 and 1.
Not sure where these rams are located but I had a hunch it may be the workrams located on the bottom pcb at location 1e which were type TMM2016P, these are common on failing.piggy backed the wram at 1e and fired it up and ohhhhh yes.................the game booted and ran,both rams replaced with new.Coined up and started playing the game but after 10mins the pic went black but sounds were playing 😟.looked into the schematics on the out rgb outputs circuitry,there are 3 colour rams which I scoped all outputs .The outputs were present but looked flacky but consistent so I ruled them out.These colour rams are addressed from 2 x 74ls157's,i scoped the 74ls157 outputs at location 6D and found outputs at pin 12 and 7 did not look very good. I used my comparator to make sure if it’s faulty or not.
Right so it's OK 👍,scoped 74ls273's outputs at location 5E and found outputs at pin 12+16 were floating ,these 2 go to the 74ls157 inputs at location 6D. Well what do you know it's a Fuckshitsu 🤬.
Powered on and.............
Game Fixed 😛
Pcb looked in nice condition except for that rgb header which was a mess.
Got it replaced.
Right now to connect up the jamma adapter and fire it up,but no luck as there's no pic or sound.Scoped the main Z80cpu on the bottom pcb for activity,all looked ok with reset good and buses active........mmmmm🧐.Decided to have a closer look at both pcbs for anything odd until I found 3 broken traces on the video board(bottom),looks like a deep scratch.
Fixed the 3 broken traces with kynar wire and fired it up and good news we have a picture but failing to boot showing error ram 0 and 1.
Not sure where these rams are located but I had a hunch it may be the workrams located on the bottom pcb at location 1e which were type TMM2016P, these are common on failing.piggy backed the wram at 1e and fired it up and ohhhhh yes.................the game booted and ran,both rams replaced with new.Coined up and started playing the game but after 10mins the pic went black but sounds were playing 😟.looked into the schematics on the out rgb outputs circuitry,there are 3 colour rams which I scoped all outputs .The outputs were present but looked flacky but consistent so I ruled them out.These colour rams are addressed from 2 x 74ls157's,i scoped the 74ls157 outputs at location 6D and found outputs at pin 12 and 7 did not look very good. I used my comparator to make sure if it’s faulty or not.
Right so it's OK 👍,scoped 74ls273's outputs at location 5E and found outputs at pin 12+16 were floating ,these 2 go to the 74ls157 inputs at location 6D. Well what do you know it's a Fuckshitsu 🤬.
Powered on and.............
Game Fixed 😛
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