Control board very hot

Hexy Questions, Problems and Suggestions
#1

Thanks for your answer to my question yesterday about the power to the Hexy system. This is what I have done so far:

I use a lab workbench power supply at 6.0 V to power the board through the Servo connection
I have run this configuration to test that each one of the servos was correctly connected and moved as shown in the specifications. I have done this using the PoMoCo software.

Everything seemed to be working ok and the servos were moving in response to changing the control sliders. Current from the power supply was in the 100-300 mA

I realized that one servo was not responsive to the command. I removed from the board. When I plugged the board again -without that servo-, without moving any of them, the current jumped to about 800 mA and the board got very hot. The part that is very hot is the Atmel chip. Unplugging all the servos from the control board gave me a current of 600 mA and still a very hot board.

During all this, the green LED stays on. I have also realized that the red LED (Status) is also on, although I did not record its state when things were working OK.

What have I done to the board? It looks like I may have fried, is that true?
I have no problems in purchasing another one, but I am concerned about running into the same problem again.
Suggestions?

Thanks again,

al

#2

This is pretty odd, I’ve never heard of the atmel chip getting hot.
Try powering from USB with everything unplugged, what happens?

Are you sure there is nothing shorting any pins on the atmel chip?

Is the ultrasonic unplugged? Sometimes people plug that in backwards, shorting the board.

#3

I have unplugged everything (including power) from the control bard and have removed it from the Hexy. The only connection now is the USB powering the board. Green PWR LED steady ON. Red STATUS LED steady ON. The Atmel chip increases temperature very rapidly after connecting it to the USB. Measuring with an IR thermometer about 3 mm from the board (not very accurate but OK for comparisons), in the other regions of the board, it reads about 24 deg C, my room temperature. Above the Atmel chip it grows up to 68 deg C before I turn it off.

Have checked the pins with a magnifying glass and have shaken the board a bit in case there was something shortcircuiting with no better results.

Given that you have not seen this behavior before it makes me think that I messed something up, so I will purchase a new board. If it will help you, I can mail you this one; otherwise, I will just get rid of it.

Al