Apr 172018

Have you ever encountered the following scenario on your beloved arcade PCBs?

Probably sometimes.The cracked component is silkscreened ‘051550’, maybe now the name tells you something :

It’s a custom IC in SIL package that can be found on countless boards manufactured by Konami (from mid 80s to late 90s).Here’s the pinout taken from a TMNT schematics:

As you can see, it performs two functions :

  • master /RESET generation for the whole system and watchdog timer
  • coin counters handling

In the below scan of the “naked” component¬† I have highlighted the part of circuit that handles the coin counters.The other part is the /RESET generation circuit which is built around a power supply monitor IC like the Fujitsu MB3773 :

You can read its datasheet here:


In this project I took into account only the /RESET function since it’s the most important and vital, coin counters can be now considered obsolete hence I intentionally omitted the relevant circuit.Anyway,¬† for my repro I wanted to keep the dimensions of the original part:


Here’s final testing on a Lethal Enforcers PCB:

See you all to my next reproduction project!

 Posted by at 6:39 pm

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