Recharge.IT – Samsung phone batteries

What happens when you are trying to fix a Samsung phone but the battery is flat, and won’t charge in the phone – for various reasons? Of course, find an identical working phone – put the battery in and charge it on that phone.

A while ago, my brother gave me a Samsung Galaxy S2 to look at. The touch-screen wasn’t working, and also the battery was flat. I also have a S2 but his battery also wouldn’t charge in my phone, so I put that aside. I opened up his S2 and was able to locate the display cable, which I think also included the touch-screen – so when I removed that connector and plugged it back in, the touch-screen started working again, so he got the phone back minus the battery.

Some time later, he gave me a Samsung Galaxy S3 to look at. This one had just stopped and would not boot up. It powers up but then stays at the Samsung Galaxy SIII GT-I9300 screen. I wrote about it here.

I have the battery for the S3 here still, so I thought about charging it. If the phone doesn’t boot up, then it will not charge the battery – very unlike a laptop. While doing a few Google searches, I came across mention of a TP4056 chip that would charge Lithium batteries. On eBay, these are very cheap – so cheap, that I ordered a few, as in five. I have this idea of getting those Lithium cells, like the 16550’s and converting everything to use Lithium instead of NiCad etc.

Of course, not everything works from 3.7 Volts, so I also ordered a few DC-DC boost converters, which will take the 3.7V and get 9V or even 12V etc. Again, not everything wants 5V, so for some things, it might like 3.3V so I also got some DC-DC buck converters. Oh, wouldn’t it be nice to have boost-buck converters?

In converter nomenclature, boost means to get higher voltage, and buck is to get lower voltage – from the input voltage – got? A boost-buck converter would be able to take any input, within reason and produce any output – within certain limits of course. They are available, but not as cheap as the boost or buck converters. Anyway, I am getting off topic.

So, these TP4056 chargers came in eventually. They can take an input voltage and produce up to 4.2V to charge a lithium cell. The charger also has a mini-USB connector on it, so I plugged in my GPS charger that can output 5V at 1A and tried it out.

I made a little jig to fit the battery and some copper wire, sort-of spring loaded to connect to the battery terminals, then used a couple of jury-rig wire clips to connect the battery to the charger. The TP4056 is set to charge at 1A which should be fine, since most phone batteries are more than 1Ah in size.


Jury rigged lithium battery charging system

The S3 battery charged ok, even though it is a 3.8V Lithium-Ion battery. Now I have a fully charged S3 battery – what do I do with it, ok – later. I thought I would try the dead S2 battery, so I connected that one, and to my surprise – it started charging. I had previously tried to charge that battery with a specialized battery charger that could handle lithium batteries, but it had failed to charge.

Now, those of you who are know something about lithium batteries will say that this won’t fully charge a 3.8V battery. Of course, the end-point full charge of a 3.8V lithium battery will be about 4.35V whereas the 4.2V is for a 3.7V lithium battery – I certainly agree, however the difference in charge level is only small – perhaps 90+% of charge, and not 100%.

Let me tell you a little secret, which most of you know anyway. A lithium battery has a certain lifetime – defined as the number of full charge cycles. Let us say, for instance that it is 1000. Most of us, will need to charge the phone almost daily – which means that in about 3 years, if we left it to charge overnight, and in the morning – the phone was fully charged, that is a charge cycle. I didn’t finish, in about 3 years or so, the capacity of the battery will be diminished – it may start to happen in 2 years, and if you are lucky, in 3 years or so. By then of course, most people have already upgraded the phone.

So if everyone knows this, how is it a secret? The secret is – what if we don’t fully charge the battery? I.e. for a 3.7V battery that has a full charge voltage at 4.2V – what if we charged it only to 4.1V – and similarly for a 3.8V battery that has a full charge voltage at 4.35V, what if we only charged it to 4.2V? We actually wouldn’t be using up charge cycles – it’s like driving without the odometer clicking over. Theoretically, that battery would still be in top condition even after 10 years! The reason is business – we want you to replace the battery, so that we can sell batteries. We want you to replace the phone since it is getting old, and the new phone can run a lot more apps than the old one. It is just that simple.

Research.IT – Samsung Galaxy S III GT-I9300 not booting

My brother sent me his Samsung Galaxy S III, a 16GB GT-I9300 android phone – it wasn’t booting. Based on his report of the symptoms, I did some research on the internet and concluded that it was most likely a eMMC failure.

When I got the phone, the first thing I did was to plug in my charger. As expected a battery symbol comes up – not expected is that it doesn’t change, normally it will show a battery level going up as it indicates that it is charging.

I tried turning it on, the Samsung screen comes up, then stays there – doesn’t go away.

Ok, that isn’t good. Next I try to go to the Recovery Settings – press and hold volume up, menu and power. The screen will eventually go off, then the Samsung screen comes up then let go.

Now this seems to indicate that the phone is unable to access partitions in its memory.

/efs, /system, /cache, /data are separate partitions in its memory which is laid out as disk storage – if these are not accessible, the phone cannot boot and is essentially now just a brick. Further research on the internet shows up a lot of information that is contradictory in both nature and content. The only promising thing about the research is that I learnt more about this android smartphone environment. There were a few references to try to correct this by erasing the Nand flash memory, however doing so will require access to a pit file, a partition information table which is similar to a MBR in disk terms.

Even finding a pit file was difficult. I was able to find a zip file on the internet that contained not one, but three pit files. Trawling through more forums, I was able to find out some critical information – the pit files are for 16GB, 32GB and 64GB phone versions, so now I was able to identify the correct one to use, the 16GB one – of course.

Another forum page suggested that we try Nand erase then Re-partition, others say never do this. Other pages suggested that it was possible to fix it by doing this and then installing the stock firmware. In preparation, I downloaded both the android 4.1.2 and 4.3 stock firmwares for this phone which was from HK. I also downloaded Odin 3.07 and 3.09 – some sites say to use 3.07, others to use the later one – I also got 3.10 just in case.

Ok, now to put the phone into downloading mode.

Now we press and hold volume down, menu and power.

Then connect the phone to the computer after making sure that the Samsung USB drivers had been installed.

Now run Odin 3.07, load the pit file, select Re-Partition and Nand Erase All, load the PDA firmware which is the phone firmware for 4.1.2


Now the time to click Start… and… Fail – ok, not unexpected.


What it means is that the Nand flash memory is basically not accessible, cannot be erased, or written which means that my original conclusion was valid – the eMMC is dead. The only way to fix this is to replace the memory chip.

I also did try with different Odin versions, as other forum pages suggest, but the result was still the same. One possibility is that the memory chip being a bga chip might have suffered a fate similar to graphics chips in laptops – perhaps one thing that I could do is to heat it up with my smd rework station, the same way that I did on the Dell laptop – maybe that might fix it if the memory chip hasn’t actually failed, so something to try…

Retell.IT – 2011 – Samsung HT-TZ315 Home Theatre System

Going through my repair books, I came across an interesting repair that I did in June 2011. It is now time to ““. I had purchased a Samsung HT-TZ315 Home Theatre System a few years earlier – it was a good price, and performed well, however I noted at the time that the display was a little dim. I didn’t think much of it at the time since everything was working fine. Fast forward to June 2011 – one day, we went to use the home theatre and the blue power light came on, but nothing from the display. The display just would not light up – but we managed to use the remote control shortcut buttons to prove that the home theatre system was indeed working – just nothing being displayed.

Ok, most faults like this are usually power supply related – I thought. The display panel uses a VFD, a Vacuum Fluorescent Display, so most likely the power to the VFD on the front panel must not be working. I removed the home theatre from the tv cabinet, disconnecting all five speaker cables, plus the optical and hdmi cable etc. After opening the box, I looked at the power supply and fortunately, the voltages are screen printed on the pcb – fantastic.


I used my multimeter to check the voltages on each pin concentrating on the vfd power – and all pins had voltage on them. Although the vfd pins were not quite +4.3V and -4.3V but were +3.2V and -30.1V – I thought that it might be fine.

I also checked the ESR of the capacitors and mostly were ok, with a few that I consider a little borderline. I proceeded to obtain replacements for those that I did not have in stock, then replaced them. After doing this, I retest the home theatre and still no display – sound was working, volume was working, just no display. From a search on the internet, it seems that problems like this require replacing the front panel pcb – AH41-01100A. From what I could find, the only replacements at a reasonable price was from the UK at around 40 pounds, ouch – not cheap when converted to AUD.

Ok, why not check the front panel pcb, maybe there is a broken track somewhere – a long shot because a broken track usually means something burning out, which is usually accompanied by other problems that would be visible. Anyway, removing the front panel pcb was eventually accomplished – need to remove a few other cables in order to get it out.

Tracing the power connections around, I eventually got to the VFD and interestingly, could not measure the VFD voltage – so there was a broken track or a dry joint.  I used a 10x magnifier and went through all of the pins attached to the power connector and where they go to, no dry joints seen. Turning it over, I could trace connectivity from the power sockets to all of the pins – what gives. After scratching my head a while, and turning the board over and over, I eventually noticed something that was slightly unusual. Two pins on the VFD were a little bent – ok, most pins should be straight since these are inserted in the factory during manufacture, but two pins, which coincidentally were connecting to one of the power circuits – the -VFD pin. When I put the multimeter probe on the pin, of course I push down, and it makes contact.


What seems to have happened is that because the pins were slightly bent when the VFD was inserted during manufacture, over time, together with transport, the solder pads on these two pins had lifted from the circuit board. Looking from the bottom, all the joints look fine, but using a 10x magnifier, I could see a gap between the soldered pin and the circuit board. I took a photo of it to show that I was not dreaming.


Here is a magnified image, you can see the right two pins have a slight dark area under the solder, this is the gap – compare with the other pins on the left where the solder pad merges well with the board. Resoldering the two pins, and reconnecting the front panel pcb – and voila! I get a display and had saved ordering a replacement board from the UK. It is also brighter than it had been originally.  The lifting solder pad had produced a dry joint that was high in resistance, but enough so that it would pass inspection since it was lit, but eventually the resistance increased due to the pad continuing to lift, until it went open circuit.

Now, three and a half years later, this same home theatre system is still working well.  You may also think, how could this happen.  These home theatre system can get reasonably hot when driving all the speakers.  This heating and cooling cycling will cause metals and plastics to expand and contract at different rates – because the pins were bent, it acts like a little spring that pushes and pulls each time the system in on and off, eventually the solder pad lifted enough that no power was going to the VFD.  The forces involved are very small, but over a period of time, like 2-3 years, it all adds up.  In addition, with a sub-woofer in close proximity, this may also cause the display to vibrate, and this would just make it worse.