Keys not registering on JPAC - please help!

[slapaham]

Well, I've been messing around with my JPac for a couple of days or so now and just when it seems like I was making progress, I get another problem.

I finally got the video syncing with my arcade monitor using Soft 15khz (I installed a spare video card which got it all working!) but now I can't seem to get the buttons functioning.

The self test LED is lit but the buttons don't seem to function. I've tried opening notepad and the buttons don't seem to do anything - anyone got any ideas as to where I should go from here?

Any help gratefully received... cheers!

[slapaham]

The Self Test LED flashes around 30 times on boot and just ends up going off after... that's the 'official' occurrence if that helps...

[Hoopz]

Check out Ultimarc's page for troubleshooting:

http://ultimarc.com/jpac2.html

I know it flashes quickly so check the switches to make sure there aren't ground problems or something not wired properly.  30 flashes on the J-Pac means P1 button 8.  But if your count on the flash is off by a couple it could be P1 button 7 or P2 button 3.  Check out the table and you can see which ones to look at. 

Take your time and check all the grounds.  Also make sure you don't have anything connected to the NC lead on a switch.  That's easy to miss sometimes.

[slapaham]

Thanks chap. I was a bit trigger happy in posting but you know how it is... it's takes you days to figure something out and you've just had enough. I think it might be player 2 button 3 causing the problem - partly because at one point, pressing that button lit the self test LED - and secondly, because it can't be any of the others you suggested as the cab only has 3 buttons per player!

I'll check over it - so if one button is out, that can potentially stop all keys from working?

Thanks again!

[slapaham]

Well, the LED lights when you press P2 B3 as mentioned before... but I cannot see any problems with the wiring. I had this cab set up playing MVS with no problems. It is jamma wired not MVS wired by the way. Any other ideas for troubleshooting?

[BobA]

Have you attached a pass thru keyboard and does it register?

[BobA]

Have you tried the advanced testing?

ADVANCED TESTING (optional)
If in DOS, enter COPY CON to suppress the command prompt. On a keyboard plugged into the pass-through, press CTRL-ALT-P. (press and hold each key in this order). Enter "T" in the menu to enter test mode. All pressed buttons and joysticks will be displayed on the screen. The input will be shown, followed by the code which is currently assigned, followed by the shifted code, if one is assigned. Test all buttons and joystick switches. If all OK reboot to exit. Now ready to play!

[slapaham]

Cheers Bob... I'll give it a go now and post up what happens. Fingers crossed!

[slapaham]

Mmm, well, I've managed to dig out an old PS/2 keyboard to try as a pass through and it doesn't work...

I'm convinced it's the P2 B3 that's causing the problem as the LED lights when I press it and I still get around 30 flashes still... but when I look at the button, I can't see any problems with it...

[BobA]

Disconnect one of the wires from the button just in case it is shorted in the switch.

[slapaham]

Disconnect one of the wires from the button just in case it is shorted in the switch.

Already tried that and it didn't work. Perhaps something shorting somewhere down the loom?

[BobA]

Unplug the jpac from the jamma connector and see if you still have a problem that will eliminate or confirm a problem in the jamma loom

[slapaham]

Well, I've just tried it with MVS again and no problems... I've tried looking at the connections/loom to see if anything is touching/loose/etc and nowt that I can see!

It's really odd that when you press p2 b3 it lights the self test LED. That's the only thing I can get any response with. It still doesn't register as a keystroke though.

[BobA]

Ok but how does the jpac show up on your PC now that it unplugged from the jamma harness?   You can still simulate a keypress by shorting one of the keys on the terminal block to ground and does it still have an error indication. The keyboard pass thru should also work if there is not external problem. If there is still a problem then it is isolated to the jpac alone and it has a problem with its programming or it is messed up.

[slapaham]

Hi Bob

I'll give it a go in a bit... thanks for the advice. If I can figure out where the problem lies that will at least help with finding the answer like you said!

[slapaham]

Right... well disconnected from the loom and with a pass-through keyboard, it works. So I'm assuming it's loom side then...

I guess that at least means that the JPac is healthy. It's just a bit of a mare as I can't see anything clearly up with the loom that would be causing any problems.

[BobA]

As pinballjim said there have been some weird problems with an ipac that was very close to HV power lines.  Andy had a fix involving capacitors.   Those ipacs would give key presses without any switch being attached.   Your problem sounds more solid so can you check your loom by disconnecting the one key that shows up when you press it at the jamma connector? Then with the wire disconnected try your jpac in the connector again.