Neo FR disassembly for bug #1024 rework
mychaela.falconia at gmail.com
Sat Jan 6 01:48:53 UTC 2018
Hello OM community,
I know that a good number of Neo FreeRunner units have been subjected
to the hardware rework to fix the infamous bug #1024, and it is my
understanding that one or more shops used to perform this rework
service professionally once upon a time. I am now looking into the
possibility of having my company Falconia Partners LLC offer this hw
rework service, as I have heard reports from FreeRunner owners who say
that their units never got the rework and do suffer from the bug, and
I would also like to be able to offer a band conversion service, i.e.,
converting any given FreeRunner between 850 MHz and 900 MHz bands in
either direction. The band conversion would involve changing one SAW
filter component at reference designator U402 (populate Epcos B7820
for 900 MHz or B7845 for 850 MHz, I have the parts readily available)
followed by recalibration - and my little company has just the right
RF test equipment setup (and newly developed calibration software that
fully replicates the functionality of the apparently-lost Windows
version used by OM/FIC) to do the latter.
The extent of required disassembly is exactly the same for bug #1024
rework and for the SAW filter change - in both cases the metal
shieldcan cover over the GSM section of the motherboard needs to be
removed, and both reworks can be done in the same surgery.
I do wonder, however, if any of the people who used to perform bug
#1024 rework in the past on a professional basis (i.e., on customer
devices, not their own personal ones) might be willing to share some
tips as to what would be the absolutely least invasive way to open
that shieldcan and then put it all back together after the surgery.
One complication that exists on GTA02 devices but not on GTA01 (nor on
my newly made FCDEV3B modems) is that the WLAN daughterboard sits
directly on top of the shieldcan cover over the GSM section, and the
two are bonded together with some material that seems to be some form
of conductive glue. It is not a strong glue, i.e., the WLAN module
can be easily pulled off by hand, but pulling it off like this leaves
a mess underneath, and thus I assume that my naive way of doing it is
probably not the right way.
Hence I wonder if any of the people who used to do the rework for bug
#1024 professionally might be willing to share the secret of how to
do it right:
1) Did you remove the WLAN daughterboard first and then lift the
shieldcan cover, or did you somehow remove these two pieces together
so they remain attached to each other with that bonding material?
2) If you removed the two pieces separately, how did you restore the
bonding between them upon reassembly?
3) If it is possible to remove the shieldcan cover along with the WLAN
module on top of it as a single piece, how does one do it?
TIA for any tips,
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