BryanMcPhail.com

Professional software development, amateur BMW tinkering, old arcade stuff

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Technos Renegade arcade PCB repair

Renegade is a JAMMA pcb and the predecessor to Double Dragon.  Initially it seemed the vertical sync was broken on this board – the image rolled vertically very fast.  I traced the sync line from the JAMMA connector back on the top board and found it goes to the bottom (video) board.  After cleaning up a lot of dirt and dust, a massive gouge in the bottom board became clear!  Must have been a fairly heavy impact as you can see two TTL pins are sheared clean off.

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Bridged the broken traces with wire and sync was restored but the image was cut into three pieces.

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Re-checked the repair with a logic probe and found no activity on one of the repaired traces.  There was actually a through-hole to the other side of the pcb in the damaged area that need soldered back on the trace.  Then everything worked 100%.

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Data East Hoops 95 pcb non-repair

This is the Data East MLC package – which is a two layer pcb inside a protective plastic box.  Unfortunately this one seems 100% dead – no video or sound output at all.  Components are actually surface mounted to all 4 surfaces on the two layers – the main CPU (an encrypted ARM) actually sits on an inside surface so it’s hard to diagnose directly.

Using a logic probe with the game powered on shows that the data and address lines on the program EPROMS are pulsing – so the CPU is definitely trying to do something.  All the graphics hardware (ROMs, custom chip) probes as completely dead – that doesn’t prove for sure that it is dead – it may be the CPU is actually failing for some reason and not instructing the graphics customs to start up.  My immediate theory would be one of the main RAM chips for the CPU has failed – these are 4 Winbond chips on the main board.  The ARM is a 32 bit chip and these 8 bit chips run in parallel so a failure in any one of them would cause the CPU program to immediately fail.

Hoops isn’t that great a game, so I’ve no plans to probe further – this can wait until I find another MLC game and swap the top & bottom boards and see what happens.

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Namco Sky Kid pcb

Bought as a non-worker for parts – actually it works 100%!  The non-obvious catch is that who-ever made the JAMMA adaptor wired it upside down!?  The tell-tale sign is the ‘double’ +5V and GND traces are on the right instead of the left.

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