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7 Posts

02-28-2016

Atlanta

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T470 Power Bridge & Boot Hang Issue

2017-06-14, 15:19 PM

Received a new T470 a couple of weeks ago, but having issues when running off battery (internal + 3 cell):

 

1. Power Bridge failure: sometimes if I unplug machine and run off batteries, then remove the external battery, the machine shuts off immediately rather than switching to the internal battery. This occurs 1/2 or 1/3 of the time.

 

2. When booting machine (if machine is unplugged, running on battery): sometimes it hangs indefinitely at Lenovo splash screen (i.e. with endlessly spinning icon). Only way out is to reset machine by punching reset button on the back. (Note: #2 occurs always after #1 occurs, and 1/2 or 1/3 of the time on a regular reboot).

 

3. However: boot hang never occurs if booting while machine is plugged in OR if external battery is removed (i.e. running with the internal battery only). Boot hang only occurs if booting off batteries and external battery is installed.

 

I called Tech Support, they sent a new internal battery, but that makes no difference. They also said it might be a faulty system board, but I ran full Lenovo HW diagnostics and all tests passed successfully including mother board test.

 

Also tried a complete factory reset (Windows 10 x64), loaded all latest updates & drivers incl. latet BIOS (1.30), which I reset to default values (F9). Problem still persists.

 

Anybody else experiencing these issues?

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1 Posts

07-08-2017

BG

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Re: T470 Power Bridge & Boot Hang Issue

2017-07-08, 15:58 PM

Hi,

I have the same problem with my brand new T570.

When external battery is plugged in AND power is disconnected, the laptop occasionally hangs on boot screen and ALWAYS hangs when trying to resume from sleep.

There are no such issues If the external battery is unplugged or if main power supply is connected.

 

 

I checked for battery firmware update but there was none.

Could it be a faulty external battery? Any other ideas on how to diagnose this?

 

PS: 

Still not contacted Lenovo support, plan to do so in a few days.

 

 

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1 Posts

07-10-2017

US

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Re: T470 Power Bridge & Boot Hang Issue

2017-07-10, 18:42 PM

I am having the same.  T470 with smaller external battery running Ubuntu.  

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7 Posts

02-28-2016

Atlanta

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Re: T470 Power Bridge & Boot Hang Issue

2017-07-12, 17:12 PM

I think I was finally able to resolve the issue, which appears to be software-related, not hardware - in fact it may be BIOS-related.  I contacted Lenovo Support several times, and they graciously offered to return/exchange for a brand new unit.  But before doing that, I tried the following steps which appear to fix the issue, at least in my case:

 

1.  Roll back the BIOS to v1.28 (obtain v1.28 from Lenovo's Driver Downloads).  My machine was running v1.30, it seems there may be an incompatibility somewhere between v1.30 and the latest Windows 10 x64, or latest drivers, etc.  (Note:  to rollback BIOS, you will first need to enable rollback in the BIOS itself - by default BIOS rollback is disabled).

 

2.  Reset Bios v1.28 to the "default settings" by hitting F9 then save/exit the BIOS.

 

3.  Do a full Windows Restore/Reset:  I did a full factory restore (i.e. Start / Search for "reset", and select full reset (don't save any files).  Then run Windows Update until no more updates are available.

 

4.  Update all drivers using Lenovo Companion EXCEPT the BIOS:  leave it at v1.28.

 

After doing all of the above, my first issue regarding Power Bridge not working went away entirely:  power bridge now works always.  However, the second issue (the boot hang issue) appeared the 1st or 2nd time I tried to reboot from battery, but when it hung, I pressed and held down the power button until the machine shut down, then I rebooted (from battery, not AC power cord), and the problem has not occured since.  It's been smooth sailing since that time.

 

One more thing I noticed:  It may be that the boot hang issue is also related to the BIOS "Wake on LAN" setting.  Even while using BIOS v1.28, and even after I reset the BIOS settings as noted above, if I then disable the Wake On LAN settings in the BIOS (i.e. disable both the "AC Power" and "Dock" Wake on LAN setttings) then the boot hang issue appears again.  But if I then reset the BIOS again to set the Wake On Lan settings to their defaults (via F9), then the boot hang issue goes away.  In fact, it seems I can cause the boot hang issue to occur or not occur by toggling those Wake on LAN settings in BIOS between "disabled" vs. "enabled" (their default value).

 

Anyway, I hope this helps, best regards.  Please let us know if discover anything else regarding this issue.

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7 Posts

02-28-2016

Atlanta

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Re: T470 Power Bridge & Boot Hang Issue

2017-08-03, 14:07 PM

One more thing about this issue:  recently, Lenovo issued updated BIOS v1.31, which has a fix for the following issue:

 

"Fixed an issue where system might not boot to Windwos in battery mode when WakeOnLan setting in BIOS Setup is disabled."

 

I applied this BIOS update, then reset BIOS settings via F9.  So far I have not had the boot hang issue.  Hope this helps.

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6511 Posts

10-29-2009

NC

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Re: T470 Power Bridge & Boot Hang Issue

2017-08-03, 16:17 PM

Yes, there was a problem with the WakeOnLAN BIOS setting.  It could cause hang while booting on battery.  It was originally discussed here:  https://forums.lenovo.com/t5/ThinkPad-T400-T500-and-newer-T/ThinkPad-T470s-BIOS-bug-WOL-and-Thunderbolt-3/m-p/3707059

 

 

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