PC Engine to DB15 adapter - help needed


Host for Orochi
10 Year Member
Apr 15, 2013
I tried to make one today using the MMmonkey tutorial: http://www.mmmonkey.co.uk/nes-to-pc-engine-controller-mod/

Result - it does not work. I double / triple checked my connections both on the DB15 and Mini-DIN cable side and all connections are fine.

My impression is that the MMmonkey schematic is missing some key components - most likely some pull up resistors. I am not concerned about the auto fire capability, just the standard two button pad.

Any ideas / links to proper PCB schematics? The ones found in the usual places are all pretty shitty - missing components, no values for resistors etc.

I done a pad hack for PCE some time ago and that worked perfect, but with current PCE pad prices / availability I do not really want to go don the road of buying / sacrificing an original PCE pad. All that is really required is a proper schematic for the 2 button pad, showing all the components and their respective values.

Any help would be appreciated.


Kyokughen Trainee
10 Year Member
Jan 28, 2009
Its probably resistors. The signal going in isn't within spec for what the PC Engine needs.

I had the same issue with a solid state floppy emulator on my FM Towns Marty. Signal curve didnt adhere to what the Marty wanted to see. One inline resistor and it recognized the emulator and worked fine.

If you had access to a Oscilloscope you could check the signal against an original pad for comparison