Z790 Taichi Lite POST Problem

Hi

I recently ran into the problem with Z790 Taichi Lite motherboard - it doesn't pass power on self test.
LED display on motherboard flashes through the sequence of codes in the loop.
Codes appeared on the motherboard LEDs are 00 C0 12 28 7F 19.
PC the motherboard is used in wasn't run a couple of months. Intel gen 13700K was there and few months ago i applied August BIOS update to solve the problem with Intel processors of gen 13 and 14.
No exposure to high temperature or excessive humidity whatsoever.
No overclocking, no gaming. It wasn't in use more than 48 hours totally.

Most of the LED codes shown above are not described in the Taichi Lite Z790 user manual.

Appreciate for any ideas that could help to resolve the issue.

The codes are supposed to cycle, each code represents a step in the POST process.
The only code that matters is the final code before the loop repeats or the code
that gets stuck on the display (depending on the situation). This last code tells
you what part of the POST process failed. Looking up that code should help identify
and resolve your problem.

All the codes should be listed either on ASRock's website or your product manual.
Some are listed as ranges: 00 - 19 for example or 31 - 3b where in 3(x) x can
be any integer from 1 to b (1-9 then a then b)

https://www.asrock.com/support/index.asp?cat=Debug

Try clearing CMOS, you could just have some bad BIOS settings saved. If a regular
clear isn't doing the trick try this:
https://forum.asrock.com/forum_posts.asp?TID=630&title=how-to-clear-cmos-via-battery-removal

If your last code is 00 that means no CPU detected, I doubt it however as code
00 is the very first code in the POST process, no other codes would show if this
one is failing. You should also check your power connections to the motherboard
and reseat the CPU if you still can't get the system to POST. While the CPU is out
double check for bent pins and dirt/debris in the socket or on the CPU contacts.

Good luck.

Unfortunately CPU reseat didn't help.
After power up the code sequence is as - 00 7F 19 00 C0 15 00 12 28
Appreciate if someone can help with codes which are not described in the Taichi Lite Z790 user manual.

I am afraid that CPU can be faulty due to known issue with GEN 13/14 Intel Core i7i9 proc.
Therefore the proper detection of problem needs to be done before Intel will be contacted for CPU replace (extended warranty).
CMOS reset is ongoing and followed by PSU tests.

Also, if you have not tried already, power on the system and leave it on for 10mins
at least. It could just be RAM training taking a long time, it can happen sometimes
but should revert to quick POST times once complete.