Interesting problems - no wifi card detected, battery lasts 2-3 hours

[dkaardal]

Model: SM-P900
OS: 5.0.2

This is an interesting one I think...

Summary

On my Note Pro 12.2, wifi cannot be enabled - it says 'turning on... ' but never actually turns on. Also, battery life (2 different batteries now) is about 2-3 hours with no apps installed or used, even if the device is on standby or totally powered off.

Background

I bought a used SM-P900 from a local guy who gave it to me for a good price because he said the devices wireless stopped being able to connect to his wifi network at home.

I took it back to my place, did a factory reset, and lo and behold everything came up fine. I could connect to my wifi network, the device was very quick and nice to use, and the battery seemed to last a good long time. I used it for a couple of weeks without any problems at all, and then one day it started having problems with the wifi connection.

Wifi issue
The unit would connect to my wireless router, but it wouldn't actually transfer data. The download arrow would flicker, but the upload arrow would not. Every so often the device would drop connection entirely, then automatically reconnect after a few seconds. Reconnection would still have the same problems - the device appeared connected, but would not actually transfer data.

After poking around the forums I decided to do another factory reset (also tried deleting cache as well). This didn't fix the issue, though it did cause a new symptom - the wifi card could no longer be found at all.

Wifi Issue #2 - wifi stuck at 'enabling'

Factory reset number 2 resulted in the device being unable to turn on wifi at all. Going through the initial setup after the factory reset, the screen where you connect to your wifi network just showed 'Turning on... ' (I think that's the text. Device isn't in front of me at the moment).

After this, regardless of any steps I take, I cannot enable wireless (or bluetooth) at all. I move the sliders and the 'turning on...' message shows for a few minutes, then the slider automatically moves back to the grey off position.

And now the battery...

After this, I noticed the battery seemed to be discharging at an alarming rate. The top back of the device would also get unpleasantly hot, and the battery would discharge at around 30% per hour - even though I'd not installed any applications at all on it, let alone run anything. This was also after I'd put it into power saving mode.

Figuring I'd come back to it the next day, I charged it up until bedtime (charge around 95%), did a complete power off of the device, and then went to bed. 5 hours later I work up and... the device was totally dead. Could not power it on regardless of anything I tried.

Flat battery, no power on... so I replaced the battery.

I bought a new battery and installed it, and now the device powers on again. Battery discharge rate is fearsome - if I power it off completely, it loses about 25% per hour. Oddly enough, if I just have it on standby it loses slightly less - around 20% per hour. This is with no applications installed (default after reset).

Tinkering with it, installing battery / CPU / process explorer apps I cannot see anything that is using much in the way of system resources. Battery capacity doesn't seem to be being reported correctly (around 3800mah) and discharge rate seems to be between -1000 and -1200

Apps I used:
CPU-Z
CPU Monitor
GSam Battery Monitor
System Panel Lite

Note: I bought a wired USB network adapter so that I could install apps on the device, since wifi is totally broken.

Troubleshooting steps tried:

Clear Cache + factory reset = cannot enable wifi (cannot find card?). Battery run flat and died.
Factory reset (x 4 or 5) with new battery installed = no effect - battery life only 2-3 hours with no use. slightly worse when device is powered off completely.

re-install OS ( Used 5.0.2 Netherlands ROM from Sammobile + ODIN) = no change
re-install OS (Used 5.0.2 Switzerland + ODIN) = no change
downgrade OS (Used 4.4.2 United Kingdom + ODIN) = no change
upgraded OS (Used 5.0.2 Netherlands + ODIN) = no change

I cannot get the wifi to enable regardless of what I do (bluetooth is the same).
I cannot get the battery to stop discharging at a very high rate, regardless of what I do (disable all non-core processes, try and track down anything using significant system resources, etc)

I've got a bunch of replacement parts on the way from China (LCD cable, charging cable, sensor cable, etc) just on the off chance it's a hardware fault with something other then a motherboard component... but does anyone have any ideas? Anyone seen this type of thing before? Wifi cannot be enabled, very high power use even after factory reset and nothing installed?

Any help at all would be very much appreciated.



Donovan.

 

[dkaardal]

Just a follow up - I figure I might as well keep my troubleshooting notes here, in case they end up being useful to anyone else in the future.

I've been suspicious that the issue with the battery life is caused by the wifi card problem, rather then being a separate issue. I've tried to disable anything even vaguely related to the network in the OS, just to see if it was something constantly trying to connect or sync even though I had the wireless and bluetooth disabled, as well as airplane mode on.

Not much seemed to be having an effect, but I did notice a setting last night called 'sync'. Yes, I'm new to android...

anyway, disabling sync seemed to have a dramatic effect on the battery life. It's still discharging much faster then I'd expect, but now it looks like the battery will last around 7-8 hours instead of 2-3 hours that I'd been seeing. Also, the unit doesn't get as hot around the camera as it was before.

Note, this is with the device on standby OR powered off entirely, and no applications running and power saving mode enabled.

So back to the wireless problem.

Does anyone know where the wifi chip is on these things? It doesn't look like it's a socketed component, so I'm assuming it's soldered onto the motherboard... but I can't seem to find it.

 

[Beut]

All Samsung tablets, wifi is built on board. A factory reset won't solve the problem, you have to change main board. A used one may be around $90 on Ebay.
Quick discharge in Galaxy Note Pro and others, mostly caused by cracked battery connector. A re solder this connector will fix the problem and it takes only under 5 minutes.

 

[muzzy996]

Definitely sounds like a hardware issue, particularly if both batteries experienced significant drain when in full power off state. There should be practically no drain when fully powered off and even standby drain on a fresh factory reset with sync off should be minimal.

 

[dkaardal]

I looked over you post on this issue in another thread (http://forum.xda-developers.com/galaxy-note-pro-12/help/unstability-caused-hardware-software-t3142081) and I'll pull out my inspection and soldering gear and take a good long look tonight. I'll update this thread once I've done so. Thanks for the tip!

All Samsung tablets, wifi is built on board. A factory reset won't solve the problem, you have to change main board. A used one may be around $90 on Ebay.
Quick discharge in Galaxy Note Pro and others, mostly caused by cracked battery connector. A re solder this connector will fix the problem and it takes only under 5 minutes.

 

[Beut]

I looked over you post on this issue in another thread (http://forum.xda-developers.com/galaxy-note-pro-12/help/unstability-caused-hardware-software-t3142081) and I'll pull out my inspection and soldering gear and take a good long look tonight. I'll update this thread once I've done so. Thanks for the tip!

This is what a Samsung Repair Center will do to fix this problem:
http://forum.xda-developers.com/showpost.php?p=59573206&postcount=100
It Works. Battery connector replaced. Smoooooth
After 2 visits to Samsung , my unit finally works fine.
Motherboard and LCD were changed first time. But issue persisted.
Second time, battery connector was replaced. Since then it has worked very very smoothly.

I doubt they actually replaced the battery connector as it takes a lot of works than just re solder the connector. Replace the connector requires the main board has to be completely removed .Re solder is simple as they only need to disconnect the battery cable and do the rework from the top of the connector.

 

[dkaardal]

Just a quick update. I've not had a chance to pick up some small soldering iron tips to do the resolder job, but I did take a very close look at them with a magnifying glass and they seemed fine.

Then I remembered I had a 20x loup and took another look - looked a little less fine, but reasonable. I did notice that one of the pins seemed to have a break in the solder though... which is rather odd, considering how solder flows. So I bought one of those little USB microscopes that Beut mentioned in one of his other threads and took another look. I'm still tinkering with the thing to figure out how best to use it, but I got a few pics.

The solder doesn't look all that bad... but it's definitely not perfect.

Hmm... it seems I can't post links to the pictures yet as I don't have enough posts to my name.

 

[Beut]

Trust me it looks fine but the trouble is from there, not just this tablet but others all have the same problem.
Look at the white female connector, it's also the source of problem if positive cables ( red ) and negative cables ( black ) don't make good contact
with six pins of black male connector. I see the trick of disconnect and reconnect battery cable many people do to fix intermittent power or battery quick
discharge, the problem is from loose female white battery connector.
You know how to solder so the fix is easy: put a little solder over red and black cables where they make contact with male connector.
You need a knife to cut these small plastic on the white female connector like this one:

This is an example of bad contact, the pin of male connector is between the opening of the tip of battery cable.
Look at two on the right side, two pins sit in the middle of the opening:

 

[dkaardal]

I'll give that a try as soon as I can get some wee little soldering iron tips. My local electronics store (Maplin) seems to be out at the moment. Hopefully I can figure something out this weekend and at least try your fixes!

Thanks again for your help!

 

[kiyoshi_vk3bzx]

Just exactly the same problem I have with my gtalaxy note pro 12.2 and I am looking for the solution.

 

[alienchaser]

I had exactly the same problem.
In the beginning, it was just a periodic disconnect.
After I have tried everything else: Factory Reset, USSD-Codes, other ROMs, Battery exchange, it got worse, so that no WiFi/BT enable was possible anymore.

When I read this thread, I started to examine the connector, I figured out, it was loose.
Then I re-soldered all the pins. But the problem got even worse. With a microscope I found out that the solder pad of PIN 3 was broken - unrepairable (because underneath the connector).
With a little speculation and a bit of courage, I guessed where this pin should continue.

I have drawn a wire between and started the pad. It had WiFi/BT from beginning and kept it stable !

I did the soldering using magnifying glasses, a 0.4 mm soldering point. But the heat is melting the plastic connector very quickly. And even very little shaking hands are too much for precise working. This is a job I cannot recommend to anyone. Will end up in more damage than repair.

The wiring was too strong and broke the part where I soldered it onto after a little bending.

I wonder, why it happens quite often, people have this problem. Maybe its a weak design which lets pin 3 broke after touching the battery connector.
Now, knowing the root cause, let me think, it was a raising connection resistance in the beginning.

(I would like to post a picture, but its not allowed to new users)

 

[Caliente_OK]

My tablet has all the exact issues. Just looking for an update from dkaaradal. Were you able to fix it??

Thanks!