Was there any lighting strike at your area?
Does the green led blink even for a second when u turn on the psu?
Is the new & old psu get warm after a while?
Btw, where did u get the new socket? Direct from Nvidia?

If replaced PSU is functioning then i'm afraid nothing can be done. Maybe can ask electronic technician try to inspect the electronic components inside.
There is one in garage sales>> https://forum.lowyat.net/topic/4437612/all

Where you bought the PSU? Could be not compatible if not for NSTV.

Need to confirm that the new PSU is working or not..
Fyi, u can use 3rd party forwarder like buyandship to ship from US to Malaysia, will cost less than RM25 now & Nvidia allows doing that under user's own risk.
I did that previously for my STV PSU replacement.

Another thing, do note that the 2019 PSU can be used with all Shield TV generation except the tube version bcoz the PSU is built-in while the 2015/2017 PSU can only be used with Shield TV 2015 & 2017 due to differences in power cut-off value but for testing purpose u can still use both version of PSU.
If 2015/2017 PSU is used with STV 2019, it will cause random reboots especially when STV 2019 is in standby mode.

Here is how to differentiate both PSU:-

The new & latest replacement Shield TV PSU will have the 'P' symbol which means the PSU is compatible for all Shield TV 2015/2017/2019(Pro).

How peculiar.

Literally same thing happened to my Shield Pro yesterday, in middle of a movie (was watching Jackie 2016). It just auto shut off and can no longer be turned on anymore.