Axon II USB communication problems

[A_Nisbett]

I've been working on a cool project using the Axon II to interface Matlab with a FANUC industrial robot arm.  I seem to have lost all Axon to PC communications through the USB cable though.  It was working perfectly and then just completely quit in the middle of executing a program.  I can still send stuff from the PC to the Axon, but nothing comes back the other way.

If it makes any difference, I'd been running the program for several hours - I have a 6V power supply for the Axon, so batteries aren't a problem.

Does anyone have suggestions on how to determine the location of the problem, and/or how to get it fixed?
Thanks, Adam

[waltr]

My suspects are:
broken wire
broken or crushed connector pin
bad solder joint
bug in the code
bad USB chip
last is the output pin of the processor is bad

With an O'scope you can look at the Axon output pin to see if the Axon is still send data.
Without a scope you could try writing code to continuously send a 0x00 for a few seconds then 0xff for a few seconds and see if the voltage on the Axon output pin changes.
If the Axon output is good then move the probe (scope or meter) to the next component or connection.

[Admin]

I agree with waltr, it sounds like a bad solder joint got knocked loose.

Get a hold of a soldering iron and re-melt the solder on the USB connector pins. Also, if you trace the PCB wiring, you'll see two wires that go from the tiny black CP2012 chip to the ATmega640. Re-melt the solder on the two pins on the ATmega640, too.

Let us know how it goes (testing with the oscope as waltr said is a good idea, but sometimes simply touching the pin with a probe will reconnect the otherwise bad connection)

[Soeren]

Hi,

It's doubtful that it should be a software issue after running good for 6 hours.

In case you haven't got an oscilloscope, here is a Poor Mans 'Scope that enables you to listen for a signal. Use at 5V max.
It will enable you to hear a signal up to a limit depending on the supply voltage.
On 5V it will be around 30MHz.
It assumes your hearing, up to ~8kHz, is at least +60dB (and you know what that means if it isn't).

Bridge the relevant output from SV1 to SV2.