was working and now its not???

[lucky2710]

I just built my first express. It had the start up message I was able to program my start channel and i successfully tested it in tst mode. But i was having issues with my dongle so i got one from pete minion (Thanks pete works great and looks good) I wen to retry the whole system together with the replacement dongle and now my express is throwing a fit!

Ive got the 3.3 led and the 5v led and the data link led lit, both sides have power left and right, BUT NOW I HAVE NO START UP MESSAGE!!! and it won't do anything no tst mode nothing???

Where do I need to start in troubleshooting this one? I'm going to try and reprogram the PIC later on tonight when i get off work but is the PIC the only place I need to check.

Also will cold weather hurt the board or any of the components? Board has been in its enclosure in my shop since last weekend and temps have dropped into the mid 30's every night this week. Could this be an issue?

[caretaker]

Cold should not be an issue BUT it could affect a solder joint that was minimal to begin with. Try reprogramming the PIC and if that doesn't work try making sure your chips are firmly in there seats (no bent legs) and touching up your solder joints

[Dennis Cherry]

Since you are using a different dongle. are you sure you have the comm port selected for this dongle?

It might be different.

[jnealand]

Since you are using a different dongle. are you sure you have the comm port selected for this dongle?

It might be different.

I can almost guarantee that the comport will be different.

[shgshgshgshg]

I have the same issue on one of my expresses it goes off and on from time to time. I can solve the issue by cleaning off the pcb with a brush and rubbing alcohol, or contact cleaner.

[rm357]

Shgshg sounds like a cold solder joint. Unless you are leaving your board exposed to the weather or dunking it in mud, it should not do that...
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Try the firmware first and let us know

[lucky2710]

Ya i updated the comport but its def an issue with the express the dongle has been tested.

[bcstuff]

I had a few LE from a previous coop that had corrupted firmware, reprogramming the PIC resolved the issue.

After programming your PIC, if the LE still isn't acting appropriately, bent pins as suggested or chips inserted wrong direction is easy to check.
 
Cold solder joints are the most likely canidate. My first build was riddled with problems, which I later resloved when I became better at soldering. Look at all you solder joints to see if they look like they are supposed too. So what are they supposed to look like?

RJs links to the Curious Inventor at the beginning of the Assembly manuals is great information. This page on their site has some nice close up pictures of good and bad solder joints.
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