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!