Jaguar controller problem: Up direction randomly disappears

[ifkz]

I recently purchased a dead ebay jaguar system that had a blown U38 surface mount power regulator. I have fixed that but now I have an odd issue: the Up direction on the joypad randomly disappears on controller port 1. I have done all of the usual fixes with no luck. I have reflowed the solder on the controller pins. I have opened the joypad and cleaned the contacts. I am hoping someone has an answer and can help, otherwise I'll have to cough up money for a new motherboard from Best Electronics.

 

For example: I was playing level 22 of Doom and almost ready to finish it when I went to the options screen for a few minutes. When I came back the Up direction was not registering (but every other button worked). It is not limited to this Doom cartridge either, it has also happened on my copy of Pitfall.

[+Stephen Moss]

Do you have another controller you can use for a while to ascertain if the problem is with the Jag (problem still occurs) or controller (problem goes away) ?

 

If you are certain the problem is with the controller then when it occurs...

If Pause, A, Right. Left & Down are still functioning correctly then you can eliminate the incoming Row strobe as the cause of the problem.

If *, 0 & # are still functioning correctly then you can eliminate problems with the Pull up resistor, 74HC244 and the output to the Jag as the cause of the problem.

 

If both the above are true then the problem has to be with either the Switch or D11 be that a physical/electrical problem or just a bad solder joint.

[ifkz]

Yes, this is my second Jag, so I do have another known good controller. I think the problem is more with the Jaguar than the controller; the lack of UP can occur right after boot, for example. If the problem is with the Jaguar, what would be the likely causes?

[ifkz]

After a day of playing Jag Doom with my original controller (E1M1 up until the Spawning Vats), I am ready to fault the new controller. No signs of problems with the original controller.

I can't find any signs of cold solder joints with the broken new controller. Looks like it will be Best Electronics to the rescue with one or two NOS Jag controllers. Thanks for the help Stephen Moss!