DSO5072P real time clock failure

hdtvguy

Hi - I have a Hantek DSO5072P which was not turned on for a long time (maybe one year). I turned it on and it was nonresponsive to many controls. I got into a utility menu and did a self-calibration. Then it was responsive to controls. However, the real time clock was set to January 1, 2009. I reset the clock to the correct date. The clock runs as long as the scope has power. After power off for more than a few minutes, the clock resets to 1-1-2009 again. I updated the firmware to the latest. The update did not resolve the clock problem. If I turn off the power for 20 minutes, the clock becomes 20 minutes slow. The clock does not appear to run with power off. If I leave the power off for hours, then it loses the time and reverts to 1-1-2009.

Is there a real time clock battery which needs replacement? I have left the scope on for a few days, to see if there is an internal battery (or supercapacitor) which needs to charge. But the problem persists. Clock only works when power is on. When power is off, it loses time/date.

Thanks for your help.