SIM7670G problems, failures, US. Core board issues?
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Unlike the SIM800L I have experience with, a SIM7670G core board I’m testing stops responding to commands via UART and to incoming SMS messages after operating perfectly for a few hours, and definitely overnight. The odd thing is, when the SIM7670G core board is connected by USB to a PC(and monitored in Putty or without Putty running) during multi-day tests, it does not fail.
This is not occurring with a SIM7600NA core board I’m also testing, it maintains a persistent connection to the 4G LTE network and never fails.
Both boards are being tested with 9VDC 3 amp power adapters, with a 470uf cap in parallel.
Why might this SIM7670G board need the USB connected to a power source? Not getting any specific support from the supplier.
Could it just be a defective board?
Has anyone else experienced this?