MLais M52 Teardown

I got stuck trying to swap SIMs and decided the put on engineers that delivered this bargain machine for £85 had not tested this and that the pins had some how bent to deny me access. As will become apparent it was the metal girdle pressing the SIM card against the contacts that was the culprit, or, more specifically, a wayward curl of plastic from the SIM itself blocking (easily removed with a sharp blade).

Anyway, on with the teardown:

The boards are visible after the usual procedure to remove the back plastic:

1. battery out, then hold the power to short any residual charge
2. undo screws (about a dozen on this monster) including one with a security sticker on it, they can be tight so have a good bit
3. nails or if they matter plastic like a toothpick

Both camera modules are instantly accessible and should their interface ever become standardised (#ahem# #project ara# #ahem#) we could find drop in replacements. I've been looking at many camera modules, for many uses, mostly for quad copters, and sadly nothing is standardised at the level of integration of flagship phone cameras.

Got your cameras out and away from dust and harm? Good. These are the locations (drawn in mauve) of the electrical connections that must be unfastened for the circuit board to be levered out.

That's showing them undone. I should go through them one by one so you needn't sweat it about breaking any when you try. Does anyone still do this or is it just the Know-How team at PC World when they grade their computers refurbished? Here goes, clockwise from the power button at the bottom left.

1. Power button - tricky this as you kneed a sharp blade slid precisely along the plastic shell to lever up the flexible button. It will retain most of its stickyness and has mechanical fixation by other means.
2. Wide ribbon - flip up the black lever where the cable enters.
3. Main camera module - lift directly up applying even force if you're careful.
4. Goodix orange chip ribbon - flip the black lever at the back where it pins the ribbon.
5. Front camera - pull connector directly upwards, don't worry about the black tape on top, it isn't connected elsewhere
6. Volume button ribbon - afforded its own ribbon connector! No expense spared! Like the Goodix connector of similar size, flip the black lever from the opposite side of cable entry

Next undo the screws, again they can be tight for a mobile phone. There are 3 in the photo but I struggled for a long time prising up the PCB because another screw is hidden under the silver tape where the connector for the volume button ribbon is opened. Carefully peel the tape back, using a sharp blade for a clean initial purchase. Don't worry too much, it's quite sticky still and there isn't really an alternative. It helps keep temperatures down.

With the 4 screws removed one proceeds to lever the PCB up from the top, be very careful at the bottom because there is a broad ribbon I couldn't find a way to disconnect running behind the battery. I must record here, because it isn't in any of  my pictures, that I couldn't find how to undo this last connector, on my Lenovo teardown it's a vertical plug in connector like the two camera modules here.

This is the rear of the PCB in all its glory. The blue square is very likely masking the MT6572, I can see the beginning of an M and it is right the size and place with enough attention given to cooling. Trying to remove the blue foam leaves a layer on the chip which isn't convenient when all the while that stubborn last ribbon is the last link between PCB and phone. With more experience and motivation I'm sure I could deal with both obstacles.

The chip models might be some use to ROM developers so here they all are beginning from the front:

What's this? Behind a heatsink the inscription,
6671122.1
1510 NX
is visible (or HX or even MX)

GOODIX
GT9157
1443-B37A
147C1200
E5L 401 xxxx (or E5I)
see http://www.goodix.com/Products/touchscreen-chip-for-mobilephone/hotknot/
This is our touchscreen controller and supports a form of NFC screentouch communication called "HotKnot" (probably only with other GT9157s)

Primary camera, ribbon marking is
JAL-JBL
-A128B
(8604)

Front camera ribbon markings:
JAL-JBL-
A128F(4-8)

On The Flip Side

a radio transceiver
MEDIATEK
MT6169V
1513-AMTH
BTP2NV39

The 2Gb DDR3 ram
SAMSUNG 516
KMR820001M-B609
Some probably unique number.


Other phones with the MT6169V
Pioneer K88L
Meizu-MX4
TCL Momoda 4G

After reading some other teardowns I notice that they aren't so easy to find and the MLais is not very anti-tamper for my part. There are some metal screens I didn't try very hard to look behind but much less than on equivalent phones, though the phones listed above do tend to have many more chips than I discovered, they are a bit older, or perhaps I am missing some.

Lenovo A820 Teardown

Follow this guide if you're worried about replacing your screen or something.

Remove tight rear cover to expose six screws, shown in yellow, the middle right one had a protective 's' security sticker over it.

Don't try and separate the plastics, the separation is performed at the screen junction with the black plastic. The screen is plastic but heavy and transparent. Slide a finger nail in somewhere and slowly work it around, hearing a click as each catch pops.

You are greeted with the backs of two PCBs. I've tip-exed out my identifying codes. The bottom PCB can be prised off but is connected at its top edge by some flat cable connector I didn't proceed to investigate further, there was little electronics of interest there and the PCB itself is paper thin.

The top PCB is much thicker and held in place by 2 very loose and obvious screws and three cable connectors.

This shows the connectors undone. Use soft plastic like a toothpick. The top one has a catch opposite the cable that flicks up. The aerial connector at the bottom left is removed with by pulling with your finger nails. The bottom right one lifts straight up. You will need to lever the PCB out of its housing. A plastic blade would be ideal, again the toothpick and metal blade would do in a pinch.

After breaking the friction with the casing movement stops after a few mm. Their is no connector for the volume rocker. The volume rocker is flexible and must be prised from the casing using a sharp knife to break the adhesive. A few mm more and some tape is found to connect a heatsink / shield on the opposite face to the SIM connectors to another "silver box" remaining with the screen part of the phone. If I had a cracked screen I should have looked further. It's very sticky tape and I removed more than I would have liked. There is one more hidden connection. Use a toothpick to prise it from the PCB as you pull it up. The connection is to the flat cable running along the battery compartment to the mic and screen connections.

This is the new face the PCB reveals, when almost completely detached (vestiges of tape remain).

On the other side of the tape are more markings.

And finally the chips, in case we're compiling our own Android and want more details.

The MediaTek markings were obscured by a pink heat sink sponge thing and this made photographing difficult. I should have tried harder to read but this is my best photo, and with reference to others I believe the markings are (lines are duplicated where there is doubt):

MEDIATEK
ARM                    APM
MT6589 W MT6589 WVK MT6589 WMK
1309-ATA 1309-ATAH
DTNFU?29 DTNFU

As usual assembly is the reverse of removal. I used a smooth plasic spatula, yeah, a toothpick, to help reattach most of the very sticky silver tape. I also wedged it under the hidden connector to increase its reactive force as I pressed the PCB down on to it.