Since 45 days passed, GearBest suggested a few options.
1) I pay for 70$ for the shipping and repair. For a 100$ meter it's not reasonable...
2) Refund 30$ on my GearBest wallet which is the option I chose.
So I'll attempt repairing this meter. Here are some pictures of the PCB:
And a zoomed-out view of the PCB:
I measured the signal sent to the buzzer when there's a continuity detected (0.0 Ohm shows on the multimeter screen):
I was quite surprised by this waveform, I was expecting a square wave. The amplitude of the signal seems variable and quite low to me.
Thank you for your suggestions!
Q1) Yes I swapped the batteries with brand new ones and it didn't fix the problem.
Q2) Yes it does show a 0.00 with the probes shorted.
Q3) I haven't!
Zermalmer, I opened it, there's no obvious damage, I haven't dropped it recently. I recently took the plane with the multimeter though I'm not sure how it would affect it...
carry on or checked baggage?
Checked baggage but it was in-between my clothes so I think it was well protected.
I finally got time to get back to this.
I tried to measure some good known resistors and notices that most of the times the readings are completely random and far off from where they're supposed to be. I can't trust this device and don't want to void any warranty, I contacted GearBest support and I'm waiting for them to answer.
I'll keep you posted with any progression on this issue. Thanks for your suggestions!
Is the buzzer on the PCB or in the case with leaf contacts touching the PCB ?
Maybe they need a clean ?
The buzzer seems to be soldered on the PCB.