Namco System 1 ROM boards repair log and ‘CUS95’ reproduction

 PCB Repair Logs, Reproductions  Comments Off on Namco System 1 ROM boards repair log and ‘CUS95’ reproduction
Jun 072019

Recently I received a pile of faulty Namco System 1 hardware.I’ve been sent boards grouped by type because, as you may know, it’s a complex system made of a smaller CPU board and a bigger ROM board.I started to troubleshoot the latter.Three of them were tagged as “working but with sound issue” when tested with the same Pac-Mania ROM set :

The issues went from corrupted sound to lack of some music tracks :

Using an audio probe I figured out the sound was properly coming out the YM3012 DAC but then got corrupted before being amplified.In the middle there are two TL084 quad OP-AMPs :

This part is well known to be very prone to failure especially the ones made by Texas Instruments manufacturer like in this case so I removed them all and they failed the out-of-circuit testing :

Replacing them with good ones restored full sound but while I was testing the boards I noticed some inputs were not working on one.A quick visual inspection revealed this :

The custom resistors/capacitors array marked ‘CUS95’ was cracked in half.Not having a spare I decided to analyze the part and reproduce it :

Three boards were fully functional now.The last one had also other issues besides sound not properly working as most of graphics were missing replaced by garbage,  sprites were barely visible :

The tilemap generation is handled by the custom ASIC ‘CUS123’ (plus the ‘CUS133’ on CPU board) which generates the addresses to the character ROMs:

It was most likely faulty so I replaced it :

This restored the graphics and left me with the sound issue to fix, music were completely missing on this board:

Replacing the two TL084 OP-AMPs didn’t do the trick this time so I went to probe the rest of circuit.I found that the 78L06 voltage regulator that provides +6 Volt to the YM3012 was outputting only +2.7 Volt :

Replacing it restored full sound.Namco System 1 multiple repair accomplished.


 Posted by at 11:27 pm
May 202019

Another reproduction of a custom IC successfully carried out.The part in question is the Sega ‘315-5025’, a 300mil DIP18 chip found on System 1/2 boards, Space Harrier and other Sega hardware from 80s :

It’s basically a shift register used for graphics functions being directly connected to data bus of the ROMs as per Choplifter schematics (it’s shown as a 20 pin IC because it’s compatible with the bigger ‘315-5155’ found on System 16A and Out Run boards)


Since nobody made it before I reproduced this custom my way by studying how it was reverse-engineered in bootlegs:

Testing on a Pitfall II PCB:

I hope this will help people to repair their faulty PCBs being understood that this project, like all my other, will not be made public although nowadays it’s a common thought that everything should be shared and free.Nothing in life is free and if you don’t work for it you certainly shouldn’t expect it, nor do you deserve it for free.

 Posted by at 9:43 pm
May 192019

‘Konami-1’, a simple name given to a custom IC used on many Konami PCBs from early 80s, here’s a filtered list from MAME :

The chip itself is a 600mil DIP42 which most of times comes with scratched-off part name:

It’s basically a 6809 CPU with some minor modifications (different pinout and scrambled opcodes), it was the first custom chip ever produced by this manufacturer.

Studying how it was reverse-engineered by bootleggers I made my own reproduction of it :

Here’s testing on a Jail Break and Gyruss (bootleg) PCBs:

Probably a CPLD based version will come later in order to semplify the board layout but I’m quite happy with it as is.

 Posted by at 11:34 am
Apr 292019

It’s big, black and squared.We are talking of the ’85H001′, a custom IC you can find on some arcade PCBs manufactured by Capcom like Ghosts’n Goblins, Legendary Wings, Section Z, Trojan, Gun.Smoke.It looks like a module with audio functions, two versions have been made.A ceramic unmarked one :

And a plastic/epoxydic one marked ’85H001 5H’ or ’85H001 5I’ :

Technically speaking the ’85H001′ can be considered a nearly complete digital sound system, all typical components (CPU, RAM, address decoder, etc.) are embedded into it with the exception of the ROM and synth ICs which are external.Actually the ’85H001′ has been already reproduced by ‘Apocalypse’ who made an excellent thru-hole version :

You can read more about in his blog :


Having found recently  a bootleg of Ghost’n Goblins with a module replacement I decided to make my own reproduction and I made two versions.An ‘hybrid’ one with thru-hole Z80 CPU/RAM and surface mounted ICs  :

And a full SMT version with Z84C0006 CPU (PQPF44 package)

Here’s final testing of both on my original Gun.Smoke PCB:


 Posted by at 6:41 pm

Konami ‘501’ reproduction

 Reproductions  Comments Off on Konami ‘501’ reproduction
Apr 282019

The Konami  ‘501’ is one of the many custom ICs you probaby encountered when dealing with PCBs from this manufacturer.Most of times the chip (28 pin 600 mil DIP package) comes with scratched-off part name, sometimes not like on my Rush’n Attack PCB:

It can be found on not so many PCBs like shown on this useful spreadsheet (credits to ‘mattosborn’ on KLOV forums)

Actually there is already a reproduction of it which uses the ColinD CPLD 28 pin board (based on Altera EPM7064S)  of which ‘Porchy’ wrote the code (available here for download).I simply made what I call a ‘poor man’s’ version using simple surface mounted TTLs gates:

Here’s final testing on the Rush’n Attack PCB:

 Posted by at 5:06 pm