[time-nuts] Ebay Huawei Ublox M8T Modules Warning

[Bryan _]

Thanks for sharing, I purchased one of the scrap modules, not the PCB mounted ones. Good catch, but if I understand your post the error is in the schematic but not the actual boards themselves. I see no schematic in the listing (maybe removed). If the boards are faulty I would have thought there would be a lot of negative feedback.

And correct the seller is very good, fast shipping and items are as described.

-=Bryan=-

________________________________
From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Nigel gm8pzr via time-nuts <time-nuts at lists.febo.com>
Sent: January 9, 2021 2:38 PM
To: time-nuts at lists.febo.com <time-nuts at lists.febo.com>
Cc: gandalfg8 at aol.com <gandalfg8 at aol.com>
Subject: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

During the December conversation re LEA-M8T modules on scraps of PCB from Ebay I commented that the same seller also had complete circuit boards available, and suggested this might be a worthwhile alternative.

I've dealt with this seller before, always been very happy with the results, and agreed a price on three such modules which arrived just before Christmas, for reference this particular Ebay ID was 333619130232, and finally found time to start checking them today.
The modules themselves look very nice, but one of the auction photos is a connection diagram that shows Pin 2 of the 8 pin interface connector as "Power In 5V DC", and on this PCB that pin connects directly to the pin 6 Vcc input on the Ublox module, which has an absolute maximum rating of 3.6V .......whoops!
This is not intended in any way to be a criticism of this seller, who I am more than happy to recommend, nor indeed of any other seller, but this is a generic diagram that several sellers are using for various Huawei/Ublox modules, some of which may have an onboard 3.3V regulator, as presumably did the one this diagram originally referenced, but some of which may not.

So that's the warning folks, don't trust that diagram without checking!
Now a question, supposing someone did follow that diagram and applied 5 Volts to Vcc on the M8T, what is the risk of damage and would it be immediately obvious?
And no, I didn't:-), but when modules are described as tested concern might arise as to the test conditions.
Nigel GM8PZR
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