Have I a partially failed Intel Z170-K mobo chipset? No USB 2.0/3.0.

Windows 7 Pro 64-bit
Motherboard: ASUS Z170-K
RAM: 2x 8GB Corsair Vengeance LPX - DDR4
Processor: Intel® Core™ i7-6700K CPU @ 4.00GHz
BIOS Date: 05/16/18 20:09:02 Version 3805
Chipset: Intel® 100 Series/C230 Series Chipset Family
System drive: Samsung SSD 850 EVO 500GB ATA Device + 6 other storage drives
Graphics: ASUS NVIDIA GeForce GT 730 Passive
PSU: 460W Seasonic Platinum SS-460FL2 Fanless SILENT

After returning from holiday, when PC was completely depowered for 9 days, saw message saying no keyboard detected when switching on.

It turns out none of the USB 2.0 or 3.0 ports are functioning. I was saved by the 2x ASmedia USB 3.1 ports which were functioning and was able to connect USB peripherals by two USB 2.0 hubs. There have been no changes other than being left without mains power for just over a week.

Apart from the non-working USB 2.0/3.0 ports the PC does not shut down correctly. Windows ‘Shutdown’ unloads running software and turns off the monitor but the power light remains on and the fans/CPU are still running. I have to hold down the on/off switch to power off the PC.

In addition ‘Restart’ behaves differently. Previously the power light remained on and the PC continued seamlessly through to the rebooting sequence. Now the PC shuts down and powers off briefly for about 4 seconds before restarting.

Although USB devices are not recognised, and there are no popup error messages, the 5v supplies at the USB ports are still there. USB devices can still be charged but there is no data connection.

I tried restoring the system drive from an AOMEI Backupper image created immediately prior to my holiday departure but the problem persisted.

All PSU voltages are normal and everything else works flawlessly with the exception of these USB ports.

I’ve tried reseating all the connectors on the motherboard and also run a memory diagnostic which checks out OK.

In Device Manager the 'Intel USB 3.0 eXtensible Host Controller’ has a yellow warning triangle. I’ve uninstalled the device and driver but, on reinstalling, receive a message stating ‘Windows encountered a problem installing the driver software for your device’ – ‘This device cannot start (Code 10). I have found more recent drivers from ASUS but they do not fix the problem.

I’ve tried reinstalling the driver in ‘Safe Mode’ to no avail.

I have also found and installed more recent MEI chipset drivers to no avail.

sfc /scannow shows no errors.

In the BIOS I have tried loading ‘Optimised defaults’ to no avail.

When depowered I have cleared the CMOS data by shorting out the ‘Clear RTC RAM’ pins while temporarily removing and checking the 3v button battery.

I have updated the Z170-K BIOS to one released in May this year but nothing has helped.

The only online description I have found near identical to my problem was at Formula | No USB Ports Working which was resolved by a replacement motherboard. My board is now over 2.5 years old so an RMA request is no longer appropriate.

I'm 90% certain it is a motherboard failure but I would like advice on this particularly if there anything else you can suggest by way of a diagnosis? Any help would be much appreciated. I have sourced a used ASUS Z170-K board just in case it is needed.

I have an ASUS ROG Z170 motherboard. From the description it would appear to be either the motherboard chipset drivers, a BIOS failure or motherboard.

First thought reinstall the Intel Motherboard chipset drivers. Many devices will not be detected or installed if the chipset drivers are corrupted.

My motherboard has dual BIOS. If the chipset drivers do not fix it and yours has dual BIOS try the other BIOS and see if that helps.

Nothing else, that I can offer. Contacting ASUS is the best next step. Good luck.

ASUS Customer Support have agreed with my conclusion the motherboard is faulty. I have also discovered it is just 2 months inside the 3-year warranty period. It is to go back to them via the distribution channel.

Replacement boards are not available as it is now discontinued but I have been able to source an identical used board. I'll await what ASUS offer by way of compensation.

And thank you for the help offered.

2 months inside the 3-year warranty period

That is fortunate.

I think it is only Gigabyte that put an extra bios chip on all their boards. Useful feature and surprising the other manufacturers haven't followed. Maybe the others only have them on their high price range.