Hi

Just for the sake of listing all the variations:

https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Is the M8T on what I would guess is the original board. Simply from looking at the picture I think
you can guess pretty well what’s what on the board.

Hint: If you buy quite a few …. errr … 10 … there s a pretty good chance that something more than
20% might get knocked off the price …. I bought a pretty large pile of stuff so it’s not clear if that
had some impact on what offers got accepted …..

If that’s not your favorite RF connector on the board, there are SMA’s that likely fit in the same footprint.

Bob

HI

Looking a bit more closely at the remains of the “chopped up” boards with the M8T’s on them …
This board is not the source of those devices. What’s left of the marking on those boards
does not line up with what’s on these (now sold out) boards.

There seems to be at least one switching regulator on this board, a CPU (with JTAG programming
connector ??),  and a fairly elaborate antenna bias / protection circuit. No idea what might be on the
back of the board.

With any luck, they will get more of these in stock.

Bob

ebay seller Queen's Land sent me this picture of the back of the cut off
board. Apparently they still have a bunch.
https://www.ebay.com/usr/queen*s_land?ul_noapp=true

Didier KO4BB

On Sun, Jan 10, 2021 at 3:47 PM Bob kb8tq kb8tq@n1k.org wrote:

Hi

There appear to be a lot of the cut off boards. The assemblies may well be
usable “as is”. It’s too bad there aren’t more of them. At the price, they are
(used to be) an attractive alternative.

Bob

With respect to the cut boards they are about 5 layers and some of the
layers are shorted by the cut. Perhaps sanding them down would allow the
boards to be used directly. My luck at popping the module off the board has
not been very successful so far.
Regards
Paul

On Sun, Jan 10, 2021 at 10:03 PM Bob kb8tq kb8tq@n1k.org wrote:

What approaches have worked to pop these modules off the chopped board?

Philip

On Mon, Jan 11, 2021 at 10:15 AM paul swed paulswedb@gmail.com wrote:

In the past removed more than 10  5T's with no problems using a Propane Torch, tapping the board and the devices did slide off. No problem.                 Noticed Bluegirls changing her listing based on Nigel's false information. For the record pin 18 of the LEA devices is a very nice feature and can feed power to an active antenna. It is a coil coupling to the RF line and according to spec up to 6 V can be applied. Short protection should be included to protect the coil. This allows user to feed an active antenna or when using a spliter no power feed to the unit saving a capacitor that I always include on telecom devices.                                                                       Bert Kehren                                                                                                                                                                                                                                                                                                                               In a message dated 1/11/2021 10:15:10 AM Eastern Standard Time, paulswedb@gmail.com writes: 
With respect to the cut boards they are about 5 layers and some of the
layers are shorted by the cut. Perhaps sanding them down would allow the
boards to be used directly. My luck at popping the module off the board has
not been very successful so far.
Regards
Paul

On Sun, Jan 10, 2021 at 10:03 PM Bob kb8tq kb8tq@n1k.org wrote:

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Hi

Pulling those modules off a multi-layer board is an art. Some seem to be able
to do it, others not so much. Applying a lot of heat (like with a torch !!!) seems
to be one way to do it. Since the module is soldered internally, it is tricky. That’s
why the “assemblies” at roughly the same price caught my attention.

Bob

On Montag, 11. Januar 2021 15:53:30 CET paul swed wrote:

I've used a hot-air station set to 350°C and high airflow with good success.
Not very difficult, what's left of the PCB doesn't have a lot of thermal
capacity. Just heat it up and slide an Xacto blade under the module. It'll
come off easily.

Without hot air - one side after the other with a fat iron tip while sliding a
blade under the pads might work, but the hot-air method is much easier and
less fiddly.

Another idea - put the modules in a steel pan, heat them on the stove from
bottom up, prod them from time to time with a knife. Eventually the modules
will come off.

Do they have a ground pad on the underneath of them which solders to the
board?

If not then I'd suggest methodically working your way round them with
solder wick, removing as much solder as you can before slipping the tip of
a fine blade under a corner to apply the slightest leverage, you then work
your way round the 'mousebites' again until you can see them separate from
the board.

I've recovered other, larger, older U-Blox modules that way.

Alternatively add low melting point solder, wick it away, repeat the
process until the 'standard' solder is diluted enough that a bit of heat
from a hot air tool to the underside of the board allows you to lift the
module off.

On Mon, 11 Jan 2021 at 17:17, Bob kb8tq kb8tq@n1k.org wrote:

--
Clint. M0UAW IO83

No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.

Are you heating the underside of the board with the hot air or the module
side? I was thinking that I'd try heating the underside of the board with
high temp hot air and then try to gently pry the module off. This probably
only requires three hands, so I should be good!

Philip

On Mon, Jan 11, 2021 at 12:57 PM Clint Jay cjaysharp@gmail.com wrote:

Hi

I don’t know if anybody else bought any of these or not.

If you did, the link now goes to a new auction (at a higher price).
That auction shows the board in it’s proper enclosure and provides a bit
more ( but not quite all) information on the module. Since they are now
free shipping a much heavier gizmo, that might explain some of the
price increase.

If you look at the box, the connector on that box most certainly is not an
HDMI connector. However it does tell you what signals are running around.
You have the PPS out on RS-422. You also get the serial out of the module
on another RS-422 pair.

The clock in / clock out stuff … no idea. The EXT-INT pin on the M8T is driven
by the 8051 CPU on the board. It’s a good bet that’s what those clocks are getting to.

The TI switcher chip on the board has it’s input clamped at 20V. It puts out 6.2V. No
idea what the correct input is. It seemed to be very happy with the 15V I put on it.
Pin 1 on J1 is power in. Pin 6 on J2 is ground. Ground also shows up on one of
the mounting holes. The other pins on J2 appear to be 3 RS-422 pairs.

All of the I/O lines are protected with clamp diodes. The antenna has multiple
layers of protection. The debug pins on the C8051F320 come out to a connector
that may or may not be populated on this or that board. There is a flash chip on
the back side and an EEPROM on the front. If somebody was more ambitious
than I am, reprogramming the MCU to do fancy stuff might be possible.

Fun !!!

Bob

Hi

Again, in case anybody else is interested ….

https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Turns out to be a bit more than what the listing implies. The parts I got
also came with a cable that goes from the round connector on the assembly
to an HDMI connector. That explains the HDMI connector pinout information
in the listing.

The big ugly “plate” turns out to be easily removed from the assembly.
That leaves you with a nice die cast box that is roughly 3 x 2.5 x 1”. It
mounts to the plate via 4 small screws.

Since you have a cable that fits the round connector, wiring it up to this or
that should be pretty easy.

Yes, the price keeps climbing ….

Bob

Apparently listing are fake Neo's, but perhaps unsoldering the pcb board may be worth the money for a module swap. Although the not sure if the M8T is pin compatible with the 7M modules. Don't see any documentation either, but I am sure there is other similar boards out there on fleabay.

https://www.ebay.co.uk/itm/Neo-6M-NE0-7M-GPS-Mini-Satellite-Positioning-Module-51-SCM-MCU-For-Arduino/142760332765?hash=item213d2dcddd:g:U6oAAOSwXeJawafs

-=Bryan=-

From: time-nuts time-nuts-bounces@lists.febo.com on behalf of Bob kb8tq kb8tq@n1k.org
Sent: February 4, 2021 7:01 PM
To: Discussion of precise time and frequency measurement time-nuts@lists.febo.com
Subject: Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

Hi

Again, in case anybody else is interested ….

https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Turns out to be a bit more than what the listing implies. The parts I got
also came with a cable that goes from the round connector on the assembly
to an HDMI connector. That explains the HDMI connector pinout information
in the listing.

The big ugly “plate” turns out to be easily removed from the assembly.
That leaves you with a nice die cast box that is roughly 3 x 2.5 x 1”. It
mounts to the plate via 4 small screws.

Since you have a cable that fits the round connector, wiring it up to this or
that should be pretty easy.

Yes, the price keeps climbing ….

Bob

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Hi

What leads you to believe that these:

https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Are fakes?

Bob

Not the previous links as but this/these ones

https://www.ebay.co.uk/itm/Neo-6M-NE0-7M-GPS-Mini-Satellite-Positioning-Module-51-SCM-MCU-For-Arduino/142760332765?hash=item213d2dcddd:g:U6oAAOSwXeJawafs

User on EEVBLOG mentions , true or not I don't know, but they did not have any luck.

https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/new/?topicseen#new

Starting at reply/post 890

-=Bryan=-

From: time-nuts time-nuts-bounces@lists.febo.com on behalf of Bob kb8tq kb8tq@n1k.org
Sent: February 20, 2021 1:53 PM
To: Discussion of precise time and frequency measurement time-nuts@lists.febo.com
Subject: Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

Hi

What leads you to believe that these:

https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Are fakes?

Bob

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Hey Bob, (and whoever else has got one of these things)
I'm curious as to what degree of progress has been made using these
little modules as-is. I know some people are pulling the M8T modules off
to upgrade other systems but I want to try and use it as it was
designed, as much as I can anyway.

Mine arrived today and I have been probing and poking at it off and on
for the past 12 hours, and this is what I have found so far:

• J3 is a standard 3v3 UART running straight into the M8T. Rx (into the
  M8T) is disabled, so you need to add a jumper link to R17. It comes
  right up with NMEA at 9600 baud, but as soon as the MCU on the board
  boots up it (the MCU) sends a message that halts the NMEA. I have
  confirmed with a logic analyzer that something is still being sent but
  I'm not sure what, maybe ubx? It isn't much, but it happens about once a
  second.. If you disconnect the main external power and feed 3v3 in
  through this header the M8T does run as a normal standalone ublox
  package would, and I am able to modify settings.

• The M8T (maybe) can't be run off of the 3v3 UART tap alone, because
  the antenna's LNA is powered from the main power, and the antennas I use
  don't seem to like running totally passively, it's probably possible to
  just pump power into this but I haven't gone that far, yet.

• I have captured what the MCU is sending to the M8T (from monitoring
  the Rx pin on the UART header) but I haven't been able to make heads or
  tails of what it means yet.

• The pinout for J2, the main connector, as best I can tell (going off
  of what you have provided):
  -- P1 - power, the docs say 15-35v, I fed in 20v and it's doing fine
  -- P2 & P3 - RS422 pair for control data into the M8T
  -- P4 & P6 - RS422 pair for data out of the M8T (maybe out of the MCU, I
  haven't traced this fully yet)
  -- P6 - ground
  -- P7 & P8 - RS422 pair for PPS

I have a few RS22/485 transceivers coming next week so hopefully I can
confirm more of this. The HDMI pinout nokia provides is a little bit
misleading because it includes a number of pins that are not used here,
namely "SingleEndedIn: REF2M_IN REF10M_IN" and "GPS_PWR_RET" - this
confused me for a little bit.

• On the bottom of the board are three chips, a 1Mbyte flash, and two
  UART-RS422/485 transceivers. Both of the transceivers are 8pin SOICs,
  one handles the control/data Tx/Rx, and the other handles the PPS.
  Something a bit curious is that one is a TI SN65HVD1474 (U3) and the
  other is a Maxim MAX3490 (U4). They have identical pinouts and very
  similar specs (20mbit vs 10mbit, respectively). Why not use two of the
  same? Vendor diversification? Manufacturer ran out of one and subbed the
  other? Curious!

• Even more curious is the way the SN65HVD1474 (U3) is configured. I
  have checked this at least two dozen times and keep coming up with the
  same results. Instead of A & B being paired, then Z & Y being paired: A
  & Y are paired, and B & Z are paired, each running the J2P7 and J2P8
  respectively. I cannot wrap my head around this. I have not yet checked
  to see what is feeding into the R & D lines of U3.

• There are three LEDs on the board, a red one which is only visible
  with the lid off that I have only ever seen illuminated, a green one
  that goes through the lightpipe to PWR, and a dual-color red/green one
  which has the following modes: flashing red 2Hz, while acquiring?
  Flashing green 2Hz (not sure, but it outputs PPS?), solid green - after
  about 20 minutes, I'm not certain.

• I have only barely started to look into the MCU, a Silicon Labs
  C8051F340. At the very least I would like to be able to dump the SPI
  flash on the back and the 8kbyte I2C EEPROM on the front. My guess would
  be that they're being used for logging and runtime, maybe calibration
  parameters? I found a C8051F340 evaluation board and it has a 10 pin
  header marked "debug", with a pinout. J7 on this board seems to be very
  close, but not identical. I'll need to dig into this one a bit more.
  Honestly, to get started, it may be as simple as holding RST high to
  just keep the MCU out of our way.

Also, I've been snapping a few pictures as I go along, they may be
useful to others:
https://photos.millerjs.org/?f=Nokia_FYGM_GNSS

And here's a capture of what is coming out of the M8T's UART once it
gets a solid lock:
Text: https://files.millerjs.org/Nokia_FYGM.txt
If you have Saleae Logic (free download):
https://files.millerjs.org/Nokia_FYGM.logicdata

Regards,
John
KK4YWH

On 2021-02-04 10:01 pm, Bob kb8tq wrote: