MAME Arcade Control Panel : Part 4

Having an impromptu day off work today whilst I wait for my new iPhone to be delivered,  I’d thought I’d continue work on my MAME control panel.

I’ve been apply the black spray top coat for most of this week and has been quite a lengthy process due to the veeeery long drying times for each coat. I’ve also brushed on two top coats of clear varnish which has provided a wonderful smooth and shiny surface (thanks Alan!). My heart sank when I applied the second coat of varnish and everything started to go a bit ‘milky’. Thankfully all was well when it dried!

With the painting finally done, I set about reinstalling the buttons & joysticks. Excitement levels increasing 🙂

It’s all starting to come together now.

Hunting out for my bag of bits from my arcade parts box, I set about arranging all the various components  like the Ipac, wiring harness and microswitches.

After attaching the microswitches, I installed the Ipac. This is the device that will relay the signal from the button/joysticks to the PC.

The Ipac board is supplied with four mounting feet which screws into the wooden control panel. The two ports shown are PS/2 style connections. One is used to connect to the PC (via the supplied PS/2 to USB cable) and the other acts as a pass thru for a  PS/2 PC keyboard if required.

With that done, I could crack on with wiring the controls. This comprises of two parts – Firstly, all of the negative contacts on the microswitches (COM) are wired in series using a daisy chained wiring harness and terminated to the negative pin on the Ipac. The pre-crimped ends help to speed up the process as they simply slot on to the microswitch terminals – unlike the first CP I’d built that had to be hand soldered (although, I missed having the excuse to weld a soldering iron!).

The second part is the ribbon of positive wires that are terminated at one end onto a standard IDC block which fits over the double row of pins on the Ipac. You have two options here, either follow the wiring guide so that each wire corresponds to the Ipac/Mame factory defaults i.e wire no.15 is button 3 or wire out of order and remap the keys in Mame. For ease, and to help locate any shorts or unconnected wires, I decided to follow the wiring diagram.

It’s here I hit a slight snag. I don’t have the wiring diagram anymore (I’d ordered the Ipac many moons ago) and a quick scan online shows that my model I’m using has been superceded – including a new wiring order 😦

I called the company I’d ordered my kit from and the really nice chap I spoke too was more than happy to email a copy of the older diagrams for me. I’m really chuffed with them, they’ve been a great help. For reference, all my arcade bits are ordered from

So, with a new (old) diagram, I set about making all of the positive connections by attaching each wire to the positive terminal on the each microswitch (NO).

I’ll point out here that, although my CP is a 1-up joystick/four button (plus x2 extra) control panel, the Ipac and wiring harness support 2-up joysticks/six buttons each and also has connections for mouse, trackballs, spinners, multiple coin and start buttons as well as many extras.

It’s all starting to look a bit messy but once I’ve tested that all is working correctly, I’ll tie wrap everything so it’s neat and safely tucked out of the way.

With all the wiring done, I connected the CP to my netbook and launched the Ipac testing software (supplied with the kit but can be downloaded here – )

Sadly, I’d hit another snag and couldn’t get a single control to work 😦 Thinking it might be a Windows 7/WinIpac issue, I swapped to the another PC running XP but still no connections detected. Thanks to the keen eye of a friend (cheers Bobby!) we’d spotted that my wiring was out by one pin therefore the negative contact was not connected. I had to practically start again and once reconnected, all worked perfectly.

Testing each control with WinIpac.


Now for the fun bit, testing it with Mame!

Everything appears to be working just fine and the controls are nice and responsive.

So that’s the control panel done. There’s just the wiring to finish off and it’ll be ready to install in the Arcade cabinet. Next job – Coin Door.




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