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How I found a hardware glitch on my Lenovo MiiX 2 10 tablet

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The article deals with problems with the power / battery for this tablet of this kind:
during the normal operation of the tablet, events begin to occur

  1. During operation, the battery indicator stops changing
  2. When you lock the screen on the curtain in the lower right corner, the battery indicator disappears
  3. In the task manager, the "Battery" device is no longer displayed
  4. Over time, the tablet "suddenly" turns off. After connecting the charger, the red LED blinks on the power button, indicating that the battery is completely empty
  5. After charging and loading, the tablet continues to fail

As it turned out, the reason for this is a hardware problem with this Lenovo tablet model.

So, I bought a Lenovo MiiX 2 10 tablet. For a while everything was fine, it worked, the OS was updated, etc. Then the failures described in the above list started. They occurred every 5-20 days. Updating / replacing drivers did not help. Since the tablet uses Windows (8.1), a simple answer came up: Windows and M $ are to blame, of course. And yes, after reinstalling (restoring) Windows, the tablet worked well. For a while I thought the issue was resolved. But reinstalling Windows once a week somehow bothered, and I gave it for warranty repairs to Lenovo official service. After a couple of weeks I got it back. The workshop (service) told me that they replaced the motherboard + screen + battery. As for the screen, it seemed like it was true - the touch screen has been very dull lately before the repair, and after that it got better. However, the crashes continued,and the warranty is over.

I continued to use the tablet - a good thing, replacing with something else was too expensive. And here, after the next reinstallation of Windows, the tablet “fixed” - it ceased to be strange with food. Rejoicing, I was about to write an article about how smart I was how I solved this difficult task, beyond the official service. But from my own experience, I knew that it was very easy to fly over in such a matter, and therefore I restored all the previous conditions under which there were problems with food. And the failures came back ...

Yeah, sometimes they come back


There are questions:

  1. Why did glitches disappear?
  2. Why did they come back?
  3. What is going on / censored / here?

Usually, in such cases, I remember the song of the Four Neblondinka “ What the hell ?! What's happening? ".

Ok, start to figure it out.

Using scientific methods, acting by the method of exclusion (subtraction (“deduction,” as mentally limited translators translate)) began to compare two states: “when it didn’t work” versus “when it worked”. A simple search led to an amazing discovery: it worked with a new access point, did not work - with the old one. The studies were lengthy, and managed to update the equipment during the experiments.

In general, how does this happen ?! Well it happens.

The points were different: the old one on {802.11n, 2.4 GHz}, the new one on {802.11ac, 2.4 + 5 GHz}.

The tablet supports {802.11n, 2.4 + 5 GHz}.

Further studies gave: the tablet worked well at 5 GHz, failed at 2.4 GHz, regardless of access points.

For verification, I bought a USB Wi-Fi network card at {802.11ac, 2.4 + 5 GHz}. In any case, the tablet worked well with her.

Again: how does this happen ?! Well it happens.

Realizing about what was going on, I began to dig further. Then I noticed that in case of failures in the “Windows Device Manager”, a certain “ HID Device»A warning icon appears. From the name of the device, nothing is clear. But there is a "hacker" trick: in the "Device Properties" on the "Information" tab, you can see some lines that describe it. I was interested in the line "Path to the device instance" containing "ITE8568". After searching, I found that the ITE8568 is very similar to the (possible) power controller for tablets and low-power laptops, the ITE IT8568 (Power IC Chip Chipset).

The reason for the failures


When using a tablet with a Wi-Fi network through the built-in adapter at a frequency of 2.4 GHz, the “ITE IT8568” power chip crashes and freezes.

What to do next


You can work around glitches without using a Wi-Fi network at all, or using an external Wi-Fi adapter by connecting it via USB. But working with the tablet is becoming too uncomfortable. With USB Type A, you can use a small Wi-Fi adapter, but the tablet has only microUSB, and the current gives only up to 0.5 A, which is not enough for 802.11ac (or a 4G cellular modem).

You can use an external Wi-Fi adapter only at 5 GHz, but then

  1. Wi-Fi range decreases
  2. Unable to use 2.4 GHz access points
  3. It is impossible to connect with many smartphones and cellular modems operating at a frequency of 2.4 GHz without 5 GHz, of which there are many, including I have.

Therefore, I prefer to return the deal.

Contact Lenovo


I bought a Lenovo MiiX 2 10 tablet that never worked properly, but crashed. I found the cause of the failures, and this is a hardware error. I understand that everyone has mistakes, so (so far) I don’t really swear. But you need to fix it. I propose to discuss possible solutions to this issue. One of them is returning to the initial state as much as possible: I give you the failed tablet, you return the money I paid.

This can be supplemented by claims for compensation for non-pecuniary damage, expenses for research, losses from failures and other things - I hope that the readers of Habr will tell me what can be obtained. Because if the thing happened and is happening in Russia, then you probably should not count on large compensation.

It would be possible to solve the problem by replacing it with a newer model, but I had to abandon Windows 10 because of a change in the Microsoft company policy regarding user data (let's call it that), and it’s not far from the end of support for Windows 8.1. T.ch. I had to switch to Linux (and a bit to FreeBSD).

March 10, 2020 Update - clarifying your goals:


I wrote this article so that any user of this tablet can find out what can be done in case of a malfunction. For an organization to start doing something, it usually needs to be given an incentive. For reference: the word "stimulus" comes from the Latin word stimulus - "the stick of an elephant drover or a sharp metal tip on a pole that drives a buffalo (bull) harnessed to a wagon."

Why it is possible to discuss falling "Boeings" and the quality of light bulbs on Habr, but it is impossible - technical details of errors in the tablet, which some users definitely have? Why not force a company to produce quality things? What mistakes should the company make to be able to discuss it here? What equipment should fail - laptops, servers, planes?

Another reason: I am preparing for the trial. How the lawsuit is filed: you come to court, you get to the court secretary, and he / she first of all asks you: “Have you talked with the other side?” It usually doesn't make sense to start a trial right away, as the parties can agree. Lenovo has a blog on Habr, I sent them a notification through the Habr servicelenovo- now I'm waiting for an answer.

I hope that, based on the results of my work, any owner of this tablet will be able to solve their problem of crashes and freezes due to the error described in the article - free repair even after the warranty period, replacement with a working model or refund. This is the action of a knowledgeable person and a responsible citizen. If someone does not defend his rights, then in fact someone does not have any rights - he himself (she) refused them (-as).

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