HTC 10 BOLT EVO Teardown - Battery replacement

[lvt]

So after 2 years of heavy use, my HTC 10 Evo's battery could only hold 75% of its original capacity. It's a very good phone so I decided to give it a new battery so I can keep it for another 1 or 2 years, knowing that the operation would be very difficult and the phone might lost its water-resistance feature.

I don't have a heatgun but after 2 years the glue seem to start losing its strength, and the HTC 10 is notorious for being hot under heavy activities so I let it dowload a very big file for a while until it becomes warm so that one of the screen's edges can be slightly lifted with a sucker. Next, a guitar pick is used to separate the screen from the phone.

Despite the age, the industrial glue used on the phone is still very hard to cut, I spent nearly an hour on the job, moving forwards centimeter by centimeter until the screen comes out completely.

But it's not done yet, the battery is hidden behind a very strong mid-frame, HTC is one of rare manufacturers who still use a mid-frame design on their phones. The mid-frame fits the phone so well that even with all screws removed, the whole assembly remains very solid. I would say you don't even need screws on this phone at all.

 

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So this is the screen assembly, a Super LCD-3 panel with very high pixels density (1440 x 2560)

You can see the fingerprint scanner cable attached to the digitizer cable.

 

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I spent another hour to clean the rest of glue on the main frame, this glue seems to resist to alcohol so the only way is to use a screwdrive blade to remove the glue residue.

Now comes another hard part of the job: removing the mid-frame.

And catastrophe happens...

 

[lvt]

When I were trying to pry the mid-frame out, one if the capacitive buttons is stuck in the way and has been sheared off...

It was an catastrophe because the capacitive buttons's cables are directly "welded" to the charging board, if one of them is broken, you need a whole new charging board.

 

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So I ordered a new charging board.

There are radio wires running from that charging board to the mainboard, there will be more jobs ahead.

To be continued...

 

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So while wating for the new charging board to arrival, I replaced the old battery with a new one and made some charging tests. The new battery has been made by the same time with the old battery and has almost no power left.

Removing the battery wasn't without some pains due to a large piece of strong double-sided adhesive, once pried out, the Li-po battery is a bit deformed.

Always completely discharge Li-on or Li-Po batteries before remove them using pry tools.

 

[lvt]

More closed view of the inside.

As we could see, this HTC 10 has a pretty clean design of the components, not messy like the M8 a couple of years ago.

The CPU and other chips are covered by a heat conducting tape and the heat is transfered to the metal case via a large copper heatsink. That's why the phone's back is sometimes very hot. It's like the whole case is a giant heatsink.

 

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Two days later the new charging board comes, so it's time to say good buy to this old part.

 

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While visually examining the new charging board, a detail made me perplexed...

This charging board has an IC (circled in red) that doesn't exist on the old board!!!

Everything is identical, except this tiny IC.

What is it?

Will this board work with my phone?

 

[lvt]

As noone could give me an answer, I don't have other choice than putting the new board in to see...

In fact, this part comes with just the board and the USB-C port, I have to reuse all cables and plastic brakets from the old board, the transfer lasts an hour due to the glue.

I only have the most basic set of tools, many important tools are missing so I did my best to accomplish all those tasks without creating further damages.

 

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All parts are assembled back and the unit is ready for test.

I have to put the mid-frame back because without it the CPU would overheat.

 

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First try, I plugged the charging cable in, the LED didn't come on... a moment of panic...

I examined the new board's USB-C port and I don't see the copper connectors in its usual aspect, this part must have sit in stock for a long time.

I put some drops of alcohol in the port and cleaned it with tiny cotton buds, praying that it's not the new board's fault.

Second try, the charging LED comes almost immediately, I'm relieved.

 

[lvt]

I temporarily connected the LCD to the phone for further tests, after all tests passed, I used two layers of the 3M 9448a double-sided tape to install the LCD back in place. 2mm width is the right choice for this phone. Applying the tape to rounded corners is not an easy task as the tape is very sticky and thin.

When the tape is ready, I installed the LCD cables, securing them with screws and the metal holder and press the LCD in place. Operation finished.

I think the 3M 9448a is the best choice because it's strong more than enough for the job, and it make the next battery change a lot easier.

The phone is not IP67 rated anymore, but I'm confident that it will survive light rain and water splash without problem.

Thanks for reading, please let me know if you have any information about the small IC that I mentioned above.