Replacement board for Gigabyte z170x-ud5

[engraverofbeams]

I have a Gigabyte z170x-ud5 th board which will no longer boot unless I unplug the power cord at the back and wait for several minutes. Have cleared CMOS, updated BIOS, reseated everything, unplugged unneeded peripherials, etc. Think it's time for a new board, but want to keep all other components (i7-6700, ATX case, DDR 4 memory). Don't care about SLI, Thunderbolt, lighting. Do need an on-baord M.2 slot. Quality of build most important to me. Any suggestions for a new board?

 

[engraverofbeams]

Also, Any thoughts regarding troubleshooting the problem would be appreciated! In a nutshell:
On power on it only shows blinking cursor upper left hand side. Won't allow entry in to BIOS. If i try to boot from a DVD or press <del> or <end> I get nothing at all, not even blinking cursor. Have reset CMOS, updated BIOS, to no avail. If i unplug power cord and let the machine sit for several minutes i can almost always get it to boot. Once booted, that machine runs like a dream! Haven't been able to get solution from Gigabyte tech support.
Gigabyte z170x-ud5 th, i7-6700 @4.0, 32 Gigs DDR 4RAM, Windows 10, booting from Samsung 960 Pro

 

[Calvin7]

GIGABYTE GA-Z270X-Ultra Gaming (rev. 1.0)
https://www.newegg.com/Product/Product.aspx?Item=N82E16813128968&Tpk=N82E16813128968

What are you using for power supply and GPU?

 

[engraverofbeams]

Ps = EVGA 550 G2
Video = Zotac VGA ZT-71115-20l
I should have mentioned that this build is exactly 2 years old and has worked fine until now. I have made no changes software-wise or hardware-wise recently. It's a mystery. Feels like the problem is getting progressively worse.

 

[engraverofbeams]

Thanks, Calvin7! That looks like a good replacement. I'm going to RMA the board and hope Gigabyte sends a suitable replacement. If they don't, or it takes too long, I'll prob.get the board you mentioned. Do you think I'll perceive a difference between the Z170x series and the Z270x series?
Also, it never occurred to me that the PSU might be an issue. I know there is a logic circuit that is reset when no power is available, and that's why it mostly boots ok when the cord is unplugged and then replugged. But i assumed that was a circuit on the motherboard. If you think there's a real chance the PSU might be at fault I'll swap it out.
Thanks for your help.