lost power to controller

After many hours of faultless performance, my 2550 refuses to turn on. I'm running two wheelchair motors off a 24v system (2 12v in series). Power to the on/off switch comes from my 12v system. I'm getting power to the switch.
It worked fine until I recently charged my 24v system batteries. I charge each battery with a 12v charger. I've charged these before with no ill effects to the controller. Unfortuantly, I'll have to tear my robot down to really find out what's going on but was wondering if there is anything I should be checking for. I looked at the fuse (auto type) and it looked okay. I'm stumped....and bummed. A complete tear down is a real choir. Thanks for any help or suggestions.
Darrell

<P style="MARGIN: 0px">If it worked and doesn't work anymore, this is usually bad news.
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<P style="MARGIN: 0px">I don't believe that this is your case but if you had an older AX2550 (2003), and applied 12V on the separate power supply (yellow wire), this input was quite sensitive to a good 12V. There had been instances where users would charge the battery while the controller is on. Voltage would sometimes exceed 14V and damage the controller.
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<P style="MARGIN: 0px">The new version lets you apply 12 to 40V on the that power input.
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<P style="MARGIN: 0px">If you can reach the 15-pin connector, I strongly sugges that you make the connection to the PC and excercise the controller using the Roborun utility. You can achieve quite a bit of diagnostic that way. Please contact us via the support form at <A href="dev.roboteq.com/dev1/supportform.html" target=_blank>dev.roboteq.com/dev1/supportform.html so that we can help you directly.

I considered running roborun but with no power to the unit, I was unsure if it would work. I'll try that and see if I can find anything. I don't remember if I made my purchase pre 2003 or not. the unit sat for a while until I could install it. Darn. I'll get back to you and thank you for the quick response.
Darrell

Oh, and the yellow line is indeed hooked up to one of the 12v batteries which were charged but again, I have charged these before with no problems. The only difference is I had previously charged the batteries together with a 24v charger. In this one instance, I charged them seperately with a 12v charger. Both chargers were battery tenders.
D.

What would make my life easier is not having to ground the yellow wire to shut off the controller. I have to use a double-throw switch so that the line can be grounded. Kind of a pain and makes it tough to use those really cool Lumex LED switches.

After recently having moved, I can't find my cable to run roborun. I've ordered a replacement. After running that, I may know more and report back.