Polar 137 XT back gauge

[Taylor Littlejohn]

Hey there, I’m new here. I work with a Polar 137 XT, and the backgauge won’t adjust, giving me an 1779 error. I’ve found the service instructions for the issue, but I do not know how to perform the necessary tasks to complete. It suggests doing a reference run, and I do not know how to do that

 

[NITIN T]

I have also same issue in Polar 137E. Back gauge reference point not achieved. Also I want to know in service mode technical data is deleted. How can restore it again ?