Can not measure DC voltage

Instruments HPS140 Handheld Pocket Oscilloscope
1

I’m just recieve new hps140i yesterday after charging battery trying to check scope
1.By test signal itself scope can measure test signal waveform
2.By measure 9Vdc battery scope can not measure always show 0V in auto-range.
3.By measure 9Vac 12Vac can read no problem.
How to solve VDC measurement?

2

Set the input coupling to DC.

3

DC input coupling nothing change still can not read DC voltage.

9Vac 220Vac scope can read no problem.
problem only on DC measurement!

Thanks

4

If your description is correct, we must suspect a problem with the input circuit.
The cause for this problem is unknown at this time.
There is a 2-year warranty on your unit, so we suggest to return the unit for inspection/repair/exchange.

5

seller give me new scope , It’s can read DC voltage. Thanks to ALL.