NExT xEM stopped working

#1

I have had my NExT a little under a month and was going good, played around mostly with the xNT side because I could just use my phone. I did add the xEM to my front door so I know it was working but about a week ago It stopped responding. I bought a proxmark3 easy to diagnose and build a pretty good antenna but I am not getting anything.
I have tried the following-
lf t55xx detect
lf t55xx p1detect
lf t55xx wipe
lf t55xx write b 0 d 00088040
lf t55xx write b 1 d E0150A48 1
lf t55xx write b 2 d 2D782308 1
still no detect
I have confirmed I have no issues with a another t55 card
lf t55xx trace looks the same as if I have nothing on the antenna

hw tune gives

LF antenna: 28.60 V @ 125.00 kHz

LF antenna: 21.59 V @ 134.00 kHz

LF optimal: 28.19 V @ 123.71 kHz

HF antenna: 25.35 V @ 13.56 MHz

and screen cap of lf t55xx trace with my NExT

t5%20trace%20
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any suggestions on what else I can try
Thanks

#2

I stand to be corrected here, I’m no expert on Proxmark commands.
The NExt is a T5577 chip but comes pre-configured as a EM4100 so it will work with the DT EM access controller.
Therefore my guess is just use a generic
lf search
and that should “see it”
Again I could be wrong, but it’s worth a crack…

#3

I suspect the antenna is your issue. It’s very difficult to read/write to the tags, the shape and position of the antenna needs to be pretty perfect. Have you ever been able to get a response from your tag using this antenna and the lf search command?

#4

I had not read or written to the xEM with the proxmark prior to needing to diagnose the issue with it. But I do understand the importance of a good antenna and positioning on the antenna. I have the test 125hz led to check position and have found the best spot on the antenna I built. lf search finds nothing

#5

do you have an xEM Access controller
to see if you can enroll it?
or
have you considered getting a proxmark lf antenna

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#6

Yeah I have the xEM Access controller and it was enrolled and working but just stopped one day that’s what prompted me to get a proxmark and investigate. Clearing the Access controller and trying to renrole gives no result also it still works with fobs. I have a feeling that the xEM silicone has died. I build an antenna to use with the proxmark and is tuned to 125khz. I dont think this is an coupling issue with the proxmark

#7

Sounds like you have done all the correct things to fault find.
It might be time to contact DT support

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#8

Ticket received… taking this internal. Thanks guys.

Amal

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