Konami '0005294' reproduction

After the '0005291', '0005292' and '0005293' another custom IC from Konami GX400 arcade hardware has been reversed., the '0005294'.This part shares the same QIP64 package of the '0005291' : 

Technically speaking it's the sprite engine of the entire system, here's pinout from Nemesis schematics :

The approach for making a replacement was the same of the other GX400 custom ICs, having a ready footprint for QIP64 package (previously realized for the '0005291') made things easier :

After some code adjusting I got the reproduction perfectly working :

Another step to a full remake of Konami GX400 hardware, stay tuned.

'NMK-903' reproduction

Thanks to the brilliant job of 'Furrtek' and 'Recreativos Piscis' another custom IC has been reproduced and preserved.

The 'NMK-903' is a small custom IC (in QFP44 package) found on arcade NMK PCBs from the 90s: 

Tracing and schematics of internal structure was done by 'Recreativos Piscis' starting from die shots made by 'Furrtek' who decapped the chip, too :

I designed a proper board (powered by a small CPLD) as replacement of this custom IC using castellated half holes :

The reproduction worked fine at first test :

A big thank again to 'Furrtek' and 'Recreativos Piscis' for their unvaluable work.

Konami '0005291' reproduction

After the last reproduction of the Konami '0005293' I reversed another custom IC from GX400 hardware, the one marked '0005291'.This part comes in an unusual 64 pin quad in-line package (abbreviated as QIP-64 or QIL-64) :

It functions as tilemap generator, here's snippet from Nemesis schematics :

After studying the behaviour of the original custom chip and gathered all info about it found on the net I started my task for create a replacement.This was quite a pretty challenge because I had also to recreate the original QIP footprint.After some time I developed a board powered by a CPLD :

The reproduction worked flawlessly at first shot :

Another step to a full re-engineering of the Konami GX400 hardware, stay tuned for next project.

War of Aero - Project MEIOU repair log

Got for repair this (never seen before) War of Aero PCB, a shooter released by ALLUMER in 1992.

Board was in very good condition :

But it was dead, no sign of life on power up.As first thing I went to check with a logic probe the 68000 CPU (in SDIP64 package) and found the clock input was stuck low :

I traced the clock pin back to a 74HC368 that drives the 16MHz signal generated by the nearby DIP14 oscillator :

Probing the output of the oscillator with a scope confirmed it was dead, no square wave from it :

I promptly removed the part :

And installed a spare :

This brought board back to life :

No other issues found so another board succesfully repaired.