Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

[GIFixed]

Dear all,
Thank you for your effort and for the good forum.

This is my first post. I have searched long time for this problems, but it seems no answer to my specific problem.

I have this laptop for a customer to check.

It is like in sleep mode and never gets out of it.
The power LED and keyboard backlight turns on shortly every about 5 seconds.
(It is like the video that was in one thread on badcaps forum - I cant find it now)

Only power off by pressing the power button for about 10 seconds. Pressing power button gets it to this sleep state again.

Could not find the write schematic and no board view. I have the NM-A74 schematic to get help from.

Details:


Lenovo Yoga 2 Pro
M/N 20266

Main board:
Kona_SVT
EBKN7 V-0

RIO board: Hannstar NS-A071 Rev 2.0
LIO board: Hannstar NS-A072 Rev 1.0


Charging seems OK
ADAPTER OK

Without charger - only battery:

Battery reseated
- S4/S5 state (DC)
- VCCRTC ? could not measure. RTC battery present.
- VIN: 7.2V
- +3VALW : 3.3V

Push power button gives:
S0 State with following voltages:
VIN: 7.2V
+3VALW : 3.3V
+5VAUX: 4.94V
+3VAUX: 0V
+1.2VSUS: 0V and momentary 1.2V every 5 seconds
CPU_CORE: 0V and momentary 1.xV every 5 seconds
MAINON: 0V and momentary about 2.5-3V every 5 seconds

If I press power button for about 10 seconds it turns off - ONLY on battery. It does NOT turn OFF if charger is connected.


When charger is connected it automatically gets “turned ON” but in this “Sleep” state. MAINON trying to turn on every 5 seconds

CPU does not get warm
No fan spin at all.
SMBUS signals shows 3.3V. Does not seem to be shorted.


When charging, coil PL7 gets hot.

Help needed. Thanks

[piernov]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

Any history?
Since it's power cycling up to CPU VCore I'd try to flash the BIOS first.

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

We dont know what the customer did before it got to this state.

Do we have the bios for this machine?

I need to buy rom/BIOS flasher. Which one do you recommend. It has to be used for PCs and Apple, etc.

[Duranitron]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

me too experienced these problem but with acer brand laptop. what i did is disable all the sleep and all pertaining to hibernation in power option in battery power option as temporary measure. it work well but of course i want to know the real problem to solve it permanently.

what i did is update the bios to the latest version it did nothing to the problem.
replaced with new memory still no avail.
reformat the whole system with new windows, still when it sleep you need to turn off the system to make it wakeup.
tweak the cmos bios option still no avail.
visual check the mobo searching for burnt or ic, mosfet with holes
check all the power 1.35v memory voltage for ddr3L 5volts, 3.3volts, 19volts, etc

until i tweak the power option in battery icon disabling all the sleep and hibernation mode. it works!!!, only problem is you don't save battery power. i contacted acer tech support only to find out. it is the nature of that acer model to do that darn thing!

i want to know the real problem and what to replace or where to check to repair it permanently. ACER tech support give up on me

[mcplslg123]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

I would have replaced LID Switch first.

[piernov]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

This is a different problem, please don't hijack other people thread. Open you own.

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

Any history?
Since it's power cycling up to CPU VCore I'd try to flash the BIOS first.

I have ordered BIOS flasher TL866 II Plus.

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

I would have replaced LID Switch first.

Where is this LID switch located?
I have no boardview.

[KvnTM]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

I had a few issues regarding the normal Yoga 2 maybe I can help you a little.
Have you checked the ram voltage? On my Yoga 2 the ram voltage was missing and it kept bootlooping every 5 or so seconds.

I know the Yoga 2 Pro is different but on mine the lid switch was located on the USB/SD Daughterboard connected by a ribbon. Just disconnecting it was disabling the lid switch to an permanent "open" state. But I highly doubt that this is your problem because if the lid is closed it won't react to the power button at all.

Could also be very well a bios issue but take a look at ram first.

I would suggest a CH341A based flash programmer. They are dirt cheap and work very well.

EDIT:
I read that it doesn't occur if a charger is present. Likely something else beside bios and ram. Does the laptop turn on/sleep normal with charger?

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

Attached an image from the schematic. I have marked the voltages who are ON with green, and those flickering with red.

[KvnTM]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

Attached an image from the schematic. I have marked the voltages who are ON with green, and those flickering with red.

Yeah it is power cycling.
Please measure +1.35VSUS.
Can be measured at PL9, PJ39 or TPF106

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

@KvnTM

The +1.35VSUS is indeed +1.2VSUS/5A on the power diagram (from the schematic). It is misspilled.
Beside it I wrote in red (maybe too small) "PJ39".

It is recycling like all the others in red.


It is hard to finde TPFxxx, or any component designations on board. It is black board. Only Diodes, coils ICs - no discrete components. That is what is doing it very hard to diagnose.

All the green power voltages are either direct from VIN or enabled by AUXON.

All other red marked voltages are enabled by either SUSON or MAINON.

Both SUSON and MAINON are power cycling.

+3VAUX is present, but almost all logic are powered from +3V rail, which is power cycling.


If I connect all cables and duaghterboards or I separate the main board, I get same result.

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

Maybe Iam wring, but what I understand from the schematic, it is the IT8586 whom is generating the SUSON and MAINON signals?

[KvnTM]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

@KvnTM

The +1.35VSUS is indeed +1.2VSUS/5A on the power diagram (from the schematic). It is misspilled.
Beside it I wrote in red (maybe too small) "PJ39".

It is recycling like all the others in red.


It is hard to finde TPFxxx, or any component designations on board. It is black board. Only Diodes, coils ICs - no discrete components. That is what is doing it very hard to diagnose.

All the green power voltages are either direct from VIN or enabled by AUXON.

All other red marked voltages are enabled by either SUSON or MAINON.

Both SUSON and MAINON are power cycling.

+3VAUX is present, but almost all logic are powered from +3V rail, which is power cycling.


If I connect all cables and duaghterboards or I separate the main board, I get same result.

OK.
Reflash your bios chip.

If all power rails are fine and have the expected voltage then it is most likely your bios. You mentioned that you can only shut it down by holding the power button for some seconds while on charger. correct? This is also a symptom of a corrupted/missing bios. Could be something else like a dead cpu but I highly doubt that.

MAINON and SUSON are outputs of the EC. It will power cycle the board if it can't read the bios rom or if it is corrupted.
Either you have a bad EC or a bad Bios. Everything else should be fine.

Off Topic:
If you think this is a hard board to work on then you haven't seen a macbook logic board. Matte black pcb with absolutely no silkscreen/designators at all. Also soldering on them is a pain. You will rip a pad just by blowing at it. I always love to have non macbook boards.

[KvnTM]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

Maybe Iam wring, but what I understand from the schematic, it is the IT8586 whom is generating the SUSON and MAINON signals?

Correct. Dont try to pull them high by injecting voltage or do something else with MAINON and SUSON. Killing your EC (IT8586VG) would be bad news since it is a BGA Chip and would be a pain to replace.

I've already had a dead EC but it is really rare from what I experienced. Most of the time the bios flash is just corrupted. Maybe the owner did a bios flash and decided to restart it or flashed a wrong bios? Who knows... Always think of the dumbest thing people could do to it. If it doesn't have water or other physical damage it's most likely some software (bios) related thing.

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

You mentioned that you can only shut it down by holding the power button for some seconds while on charger. correct?

No, it is when only on battery I can turn it off by holding the power button for some seconds.
It does not turn off, when charger is connected, regardless of battery.



Well, I worked a little bit with macbook boards, but only with a shcematic AND boardview.

I will try to get the BIOS dump from this site. But when flashing BIOS from donor board, it does corrupt the windows key, wright?

It is my first time to flash a BIOS by hardware.

I am new to real diagnosis of laptop boards. I am in a no-pay intership and trying my best to learn this, so I can get a job.

Many thanks for your help.

By the way, I have read on internet, these yoga laptops (and maybe others) get their BIOS corrupted by windows update.

[KvnTM]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

No, it is when only on battery I can turn it off by holding the power button for some seconds.
It does not turn off, when charger is connected, regardless of battery.



Well, I worked a little bit with macbook boards, but only with a shcematic AND boardview.

I will try to get the BIOS dump from this site. But when flashing BIOS from donor board, it does corrupt the windows key, wright?

It is my first time to flash a BIOS by hardware.

I am new to real diagnosis of laptop boards. I am in a no-pay intership and trying my best to learn this, so I can get a job.

Many thanks for your help.

By the way, I have read on internet, these yoga laptops (and maybe others) get their BIOS corrupted by windows update.

Make a backup of your bios first before overwriting it!
And desolder the flash chip. Do not flash it in circuit. This could kill your EC. The board has protection resistors on the SPI data lines but I wouldn't try it since on many EC's the SPI bus runs at a lower voltage than 3.3V. Your programmer probably runs on 3.3V.

It's pretty rare that Windows corrupts your Bios but who knows. Windows usually has no access to write the Bios rom. But many wonderful things can happen. I had an Asus Laptop which killed itself for no reason at all. Reflashed the Bios and it was fixed.

Your Windows key will be gone. That is correct. And you have to clean the ME region of the Bios dump or it will take 10 or 20 Seconds to POST. Be aware of that when you flash it and turn it on. Just let it sit for a Minute if it stays turned on.
If the Lenovo Logo doesn't appear after a Minute max you probably have a wrong Bios dump. But would be great news if it stays on at least.

There is probably some Tutorial here on how to clean the ME region or someone else could probably help you out on that.

There is a really simple path to follow:
Look for water/physical damage
Check all power rails.

Measure resistance on failed power rail. Resistance too low or shorted to gnd? Probably a shorted cap somewhere. Inject the expected Voltage with current limit and look what gets hot. Replace part that gets hot. Repeat.

Resistance on power rail seems ok? Probably a failed buck/boost converter chip or some signal is missing. Look at Datasheet of the part and check every signal it needs to turn on.

All power rails present and turns on with no display and cold CPU? Check Bios

If you can rule out power rails and bios it probably is some chip which can be annoying to pinpoint.

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

Make a backup of your bios first before overwriting it!
And desolder the flash chip. Do not flash it in circuit. This could kill your EC. The board has protection resistors on the SPI data lines but I wouldn't try it since on many EC's the SPI bus runs at a lower voltage than 3.3V. Your programmer probably runs on 3.3V.

It's pretty rare that Windows corrupts your Bios but who knows. Windows usually has no access to write the Bios rom. But many wonderful things can happen. I had an Asus Laptop which killed itself for no reason at all. Reflashed the Bios and it was fixed.

Your Windows key will be gone. That is correct. And you have to clean the ME region of the Bios dump or it will take 10 or 20 Seconds to POST. Be aware of that when you flash it and turn it on. Just let it sit for a Minute if it stays turned on.
If the Lenovo Logo doesn't appear after a Minute max you probably have a wrong Bios dump. But would be great news if it stays on at least.

There is probably some Tutorial here on how to clean the ME region or someone else could probably help you out on that.

There is a really simple path to follow:
Look for water/physical damage
Check all power rails.

Measure resistance on failed power rail. Resistance too low or shorted to gnd? Probably a shorted cap somewhere. Inject the expected Voltage with current limit and look what gets hot. Replace part that gets hot. Repeat.

Resistance on power rail seems ok? Probably a failed buck/boost converter chip or some signal is missing. Look at Datasheet of the part and check every signal it needs to turn on.

All power rails present and turns on with no display and cold CPU? Check Bios

If you can rule out power rails and bios it probably is some chip which can be annoying to pinpoint.

There is no sign of water nor physical damage.
I have measured all power rails and could not find any short to GND.

I was afraid of injecting power on power rails not to blow the EC, CPU and anything other. At work we have the HP Agilent power supply with current limiting as in attached picture.

[KvnTM]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

There is no sign of water nor physical damage.
I have measured all power rails and could not find any short to GND.

I was afraid of injecting power on power rails not to blow the EC, CPU and anything other. At work we have the HP Agilent power supply with current limiting as in attached picture.

There is no need to inject voltage into the board at this point since all power rails seem to be ok. Could be some current sensing circuit but I doubt that. Injecting power only makes sense if a power rail is shorted and you can't find the bad component. This is not the case here.

The Yoga is just power cycling. I guess a reflash of the bios will do the trick.
The EC should be fine since it does do something. A dead EC would usually prevent the board from starting at all since the power button is connected to it. Do you have access to an oscilloscope? You could monitor the SPI data lines on the bios chip.

[GIFixed]

Re: Lenovo Yoga 2 Pro 20266 Stuck in sleep mode

Unfortunately, we dont have an oscilloscope. But I personally have this logic analyzer, but never used it:

https://www.ebay.com/itm/USB-SALEAE-...a9987303219201

Is it usable?