Ax3500 - Not Responding

Hi,

Whilst out driving the robot yesterday it suddenly stopped, the AX3500 board showed a constant 8. (under/overvolt). We took it back, connected the charger with no result.
The robot was left switched off overnight, tried again in the morning and it is still showing the 8. even though the battery voltage is 24.9v (with all systems running).

I tried to connect to the board using the roborun software but it is not being "found". However if the roborun software is set to "run" in the split second that the "U" is displayed the board sends out garbled rs232 responses... e.g:

1st try: ?w?ote?q
2nd try: ??{?{7??
3rd try: ?wotb??w
4th try: ???~?{
otherwise the board does not respond to any commands except the %rrrrrr reset code.

I've also tried the self test which displays: 1-9-*stops and goes blank* with no response from the motors.

I am not using any encoders and the robot has been working fine since the board was installed in Febuary...

Help!

If you have a voltmeter, measure the 12V and 5V test point on the board. If the 12V is less than 11.5V feel with your finger if any component is hot.

The 12v test point is at 5.9v (both measured on the test point and on the regulator) and the 5v test point is at 4.6v.

No components are hot, but the middle of the board on the rs232 side (i.e. below the large 5v regulator) gets slightly warm.

5.9V on the 12V test point is definitely a sign of serious problem. Typically a blown MOSFET driver. Please contact us using the form at <A href="dev.roboteq.com/dev1/contactus.html" target=_blank>www.roboteq.com/contactus.html to arrange for a repair.

Will do.
Thank you for your help!

Here is a thermal image of the board.
Nothing is hot, although some parts get a little warm.

<img src="michaelt.uwcs.co.uk/cropped1.jpg">

I\'ve encountered this problem again - as before, it\'s an AX3500 and there wasn\'t anything much in the use or handling which could have caused the problem.

With a 24v supply, the 12v rail shows 4.6v, the 5v rail shows 2.6v, and component U9 (an HIP4081A) gets extremely hot.

This board is only a few months old - we brought it from Active Robots in the UK.

What should we do in this situation?