"OSError: Couldn't connect to Modem!"

[mretallack]

Hi,

I have a FiPy and am using an Expansion Board 3.0 board.

I have found that on startup from cold, the LTE modem returned the following error (as per the parent topic):

"OSError: Couldn't connect to Modem!"

During investigation I found that it did this when connected to a USB power brick, but not when directly connected to my Laptop.

I replaced the USB cable between my laptop and Expansion Board 3.0 with a "2 wire" power cable instead of a full USB cable and it started to work.

My current theory is that the Custom PIC is effecting the startup when powered by a USB brick instead of a laptop.

I have also powered the FiPy directly using 3.5-5v and GND pins and this seemed to work.

Has anyone else seen this? Without the schematic its difficult to see how this could be.

[oligauc]

@mretallack What are the current / voltage ratings of the USB Brick ? With a multi-meter can you read the actual current when the modem is trying to connect ?

[mretallack]

@oligauc Hi,

The I have tried a number of USB bricks, ranging from 5V at 0.8A to the current one that is rated at 5v at 2.5A.

I have also checked the voltage on the Fipy pins and the measured voltage was between ~4.7 and ~4.9v. Strangely when it was working it was 4.7 and not working 4.9. I can only assume this is because the Modem was in some strange state so not loading it as much.