Sep 102019
 

As someone may recall I’ve recently done a reproduction of the custom ‘CUS99’ used on Namco PCBs :

Namco ‘CUS99’ reproduction

After done it I thought it was good to take into account its “companion” too, the ‘CUS98’  which most times come along with the first.Package is pretty the same but with two further pins than ‘CUS99’

 

But functions are totally different and,  as Rolling Thunder schematics suggest,  the main one is to generate the master reset :

Secondary functions are coin counters and lockouts handling as well as lamps driving, it seems only few games (like Pac-Land and Gaplus) use this last feature :

I was obviously interested in reproducing at least the reset generation function which is essential for correct operation of the PCB  (but it seems Rolling Thunder can boot into game also with a missing ‘CUS98’).Therefore, as usual, I studied earlier Namco hardware where the custom had not yet been used and I came to a prototype developed on a breadboard:

The protoytpe worked pretty good :

Hence I developed a proper board :

Final testing on a Pac-Land PCB:

As said some functions have been intentionally omitted favoring the needed ones (watchdog circuit ad reset switch were implemented too).This will at least allow to save PCBs with a faulty/broken or missing ‘CUS98’.

 Posted by at 8:10 am

Irem ‘KNA6032701’ reproduction

 Reproductions  Comments Off on Irem ‘KNA6032701’ reproduction
Aug 112019
 

Another custom IC successfully reproduced, it’s the Irem ‘KNA6032701’ , a 42 pin DIP 600mil IC used on M62 (Kung-Fu Master, Lode Runner, Spelunker and other), M75 (Vigilante) and M72 (on some  type of ‘M72-B-D board) hardware

As usual I reproduced it my way by observing how it was reverse-engineered on bootleg boards obtaining in a board layout with pretty same dimensions of original part :

Testing on a Kung-Fu Master PCB :

 Posted by at 10:26 am

Konami ‘083’ reproduction

 Reproductions  Comments Off on Konami ‘083’ reproduction
Jul 262019
 

This is another ‘poor man’s’ custom IC reproduction I made with no use of CPLD or other complex programmable logics.The part reproduced is the Konami ‘083’, a 28 pin 600 mil in DIP package which most of times comes with scratched-off part name :

It can be found on several Konami PCBs, you can refer to this useful spreadsheet (credits to ‘mattosborn’ on KLOV forums)

https://docs.google.com/spreadsheets/d/1iB9BJaEpAufgKaz758FiDDekUH8JreoTn276yPqD-kk/edit#gid=0

As always I observed how its functions were reverse-engineered on bootleg boards and made my own reproduction with simple TTL gates logics :

Final successful testing on a Mega Zone PCB:

 

 Posted by at 11:05 am
Jul 262019
 

The ‘CUS99′ (simply silkscreened ’99’) is a custom IC used on Namco arcade PCBs.It’s a 16 pin SIL component covered with a brownish coating :

It can be found on pre-System86 (Pac-land, Sky Kid, Gaplus, Dragon Buster and other boards..), System86 (Rolling Thunder and other games on same PCB layout) and System 1 hardware.From the scarce info about it the ‘CUS99’ is involved in sound volume control but we knew nothing more detailed about, pinout from official schematics apart :

Recently I’ve been sent by the user ‘JorgePT’ a pile of System 1 boards for repair hence, with his permission, I analyzed the part. After drawing schematics of its internal structure I came to the conclusion that the ‘CUS99’ is nothing more than a 4-bit DAC with output level control performed by analog switches.Its design was quite simple and easy to reproduce with few parts  :

Testing of the repro on a Pac-Land PCB was successful:

Thanks again to ‘JorgePT’ for his willingness.

 Posted by at 10:32 am
Jul 262019
 

Here’s a repro of the KNA 6032601 found on boards like Kung Fu Master and Tropical Angel.

While it’s not known to fail as often as the KNA 6034201 (which Caius has already made a repro of ) it has been know to start failing lately.

 

It’s a 40 pin custom IC on the TOP board of the kung Fu Master stack, sitting at E1 & E2 between two rams and the colour proms

This most likely deals one deals with the final image processing, like layer priorities, just before outputting data into the colour proms

I used a bootleg to see how this one was reverse engineered by bootlegers at the time and identified and area between the rams and the colour proms.

Tracing multimeter confirmed those 9 LSxx ICs were indeed connected to the same ICS as the custom. So I fired up easyEDA and got busy .

A few days later, voila! a working IC and a working board. Not a complicated thing to do, it just takes time to trace back everything .

Huge thanks to Caius for his recent inspiring work on making repros for a lot of these custom ICs and has prompted me to look into the topic and start making my own too. The more the better !

And as usual, for those who prefer the video format :