Ipac - many extra Mach inputs via the keyboard port

[Gerald D]

The IPAC (http://www.ultimarc.com/ipac1.html) was all the rage with the Mach guys about 3 years ago - very seldom mentioned these days. (needs a tiny capacitor on each line to make it immune to noise in our environment)

http://www.ultimarc.com/images/ipac2_diag.jpg

Gives you lots of extra inputs via the Keyboard (PS2) input

[myozman]

The Ipac is what I use for all the arcade games I build. It's pretty simple with good software to program. There are others, but I have had the best luck with Ipac. Some have been running for several years without a problem.

[Gerald D]

Copied from discussion which started at: http://groups.yahoo.com/group/mach1mach2cnc/message/48116

Capacitors on all inputs except:

One of the input lines is used to communicate with the on-board EEPROM. Another 3 are pulsed because they control LEDs so connecting capacitors to these is not a good idea. If you avoid the following inputs you would probably be OK:


1 SW 8 (EEPROM)
2 SW 7
2 SW 8
1 SW 7
1 SW 6



Will this capacitor work for noise suppression in the IPAC?

0.1 UF, 50V
Kemet C410C104M5U5CA
Z5U, 20%

It is a axial capacitor if that matters.

I also hear that their is a ground run on the back of the boards that pretty
much runs parallel with the inputs. Easiest to install the caps there??

Yes, just scrape off the green solder resist coating and away you go. It
can be a bit fiddly to fit the caps but they do make a huge difference.

Yes, that's how I installed them, there is enough room to drill a hole
for the ground lead and wire the other end of the cap directly to the
pin on the underside of the board, then you can push the caps down
flat.