Odd IPac Behavior

[Squid]

I've been working on building a MAME control panel for sometime now and finally see the light at the end of the tunnel.  I designed it in such a way that I could create different panels that slide into the case making it easy to change layouts depending on what I wanted to play.

I decided to "modularize" things a bit with respect to the IPac as well.  I mounted the IPac into a Radio Shaft plastic project case using nylon standoffs.

Next, I thought it would be a grand idea the following for connectors on the project case.

DB-9
Pin 1 - Ground
Pins 2-5 - Player 1 to 4 Start
Pints 6-9 - Coin 1 to 4

DB-25 #1:
Pin 1 - Ground
Pins 2-5 - Player 1 Joystick Left, Right, Up, Down
Pins 6-9 - Player 1 Buttons 1-4
Pins 10-13 - Player 2 Joystick Left, Right, Up, Down
Pins 14-17 - Player 2 Buttons 1-4
Pins 18-21 - Player 1 Buttons 5-8
Pins 22-25 - Player 2 Buttons 5-8

DB-25 #2:
(same as #1 for players 3 and 4).

Using said configuration would allow me to attach a two player control panel to the IPac case using 1 DB-9 cable, and 1 DB-25 cable.  All was going well and everything hooked up and I tested the DB-25 connectors once I mounted them to the project case.  All buttons were functioning properly.  I tested them by inserting a wire into the ground pin of the connector I was testing and, one at a time, sticking the other end of that wire into the DB-25 pin-hole of the button that I wanted to test.  Great, everything was working and all buttons were working too.  The panel looked very clean, the project case, although a little large, was also clean.

Then came the odd behavior.  I fired up the WinIpac application.  As soon as I attached a DB-25 cable to the Player 1&2 DB-25 connector, Player 2's button 7 stuck.  I unplugged the cable and voila, unstuck.  Reattached it, stuck.  Ok, bad cable, grabbed another one... argh!  Same thing.  I spent the next couple of frustrating evenings rewiring the entire connector over again... three times.  Every time, either that button, or both that button AND Player 1's button 7 stuck.

Trying to recall those, now very foggy, college electronics courses I was trying to surmise what was happening.  I thought perhaps there might be an "Open Collector" problem with the IPac's inputs.  The buttons were not even attached yet.  Just a 10 foot DB-25 (Male to Female) cable with the male end plugged into my Radio Shaft project case with the male end unattached.

Has anyone else experienced anything else like this with the IPac, or does anyone have any suggestions as to what might be the cause of these problems.

Appreciate any feedback.

[Squid]

Some pictures (LOUSY ones )

Picture of the case with the panel sliding out.

[Squid]

Ground wires attached to panel.

[Squid]

Rear view with panel in place.

[menace]

Sorry I can't help you with your IPAC (andy warne is the guy to talk to about this) but I must say that I like your sliding control panel idea

[PhoneGuy]

Try reducing the overall length of your cable.  I used 25 pair amphenol cable for quick disconnects between the I-PAC 4 and the CP.  I was getting the same stuck key problem. I noticed if didn't have the half of the cable that was to attach to the CP connected, the stuck keys went away or pulsed.    After rewiring with different cable, I still had the same keys sticking.  Finally I reduced the total length the cable to less than 2 feet. The stuck keys went away. I had started with about 6 feet of cable.  The amphenol cable wires connect to a barrier strip in the CP.  Wires between barrier strip and the buttons are not part of my 2 foot limit.  

Email from Andy at Ultimarc indicated some of the inputs serve a dual function for lighting LEDs which may cause a problem when using a long cable.

[wescotte]

Are you sure the DB25 cable is a straight thru?

[Squid]

Yes.  I double checked the cable with a multi-meter too just to make sure.

[Squid]

Phoneguy:  I also noticed the pulsing/flickering as well under some circumstances.  I suppose I just found this strange because it only ever happened on one or two buttons, not all of them (or random).

[bigmoe]

Very nice on the sliding panel.

Could the stuck key problem have something to do with the fact that P1-button7 and P2-button7 are also used for the LEDs?  (Phoneguy: were you getting a different key stuck?)  Perhaps avoiding using button 7   would be an alternative?

b

[SirPoonga]

Talk to Andy at ultimarc.  I had a simular problem and it ended up being the ipac at fault.

[PhoneGuy]

I was having trouble with P2B7. Here is Andys reponse when I ask about cable length once I discovered using less cable stopped P2B7 (j key) from being "stuck on:

"Three of the I-PAC connections also deal with the LEDs. To control the
LEDs these inputs switch between reading and driving (ie driving the LEDs) and what is probably happening is a capacitance effect, if the wires are all bundled together, causing a residual charge when they change over from reading to driving or vice versa. The way around this would be to shorten the cables or not bundle the wires all together. This does seem a bitlong, 10 feet. The I-PAC is normally mounted right next to the controls."

[Squid]

Right.  I wanted to avoid having to purchase a new IPac for each control panel (mostly from a cost savings point of view, though it's not major).