EG800 sim failure out of the blue

IoT Modules LTE-A Module
1

Hi,

We are evaluating the EG800 as a replacement for the currently used lte-m in our products. I’m using the evaluation board (EG800QEULC-N03-TA0AA) with motherboard (UMTS&LTEEVB-Kit) and everything went fine.

All of the sudden the SIM card is not functioning anymore but the card is working in other modules. If I check the VDD on the sim card holder then I see that the voltage is not there.

Is there any setting for this? Did I changed something accidentally? Are there schematics of that motherboard.

I also noticed that some SIM cards were working flawlessly and others needed several power cycles to start, before everything started to fail.

This is a kind of a show stopper.

2

Update:

I checked and see that the SIM_vdd of the motherboard is coming straight from the sim_vdd of the module.

Are these modules having a problem with the SIM interface?

I recall how this happened:

I had an active PPP session and I want to drop the carrier by pushing the power button to power down state. This power push button didn’t respond to anything so after I while I gave a reset. After that, the SIM interface is not usable anymore and even a factory reset wont bring it back.

Firmware issues???