Hi @tcg6000
We understand your urgency, and an RMA will take some days to complete on our end.
I can provide you with a part number, but you need to be aware of a couple things:
That part number, should you still wish to replace on your own is (here is a digikey link):
https://www.digikey.com/en/products/detail/littelfuse-inc/SMF4L17CA/10710004
If you review the specs, you'll note it starts to conduct ~19V, hence why @21V if it was sustained, effectively looked like a short circuit to the power supply, and the TVS was exposed to the condition long enough to short it out too... (at least that is my opinion)
I will follow-up internally on that free replacement power supply order today. I'll try to make sure it get's processed today or tomorrow.
Let us know what you decide, and if you do replace it, let us know if that fixed everything for you.
Thanks!
Vinny