Hello,
Currently, I have a non-working Polyend Seq. From what I understand, the previous owner tried to power it with a 12V power supply instead of the original 5V. It appears that U2 (a TPS211xA chip) has blown. The issue is that the chip is badly damaged, and I can’t read the full marking to determine the exact model (e.g., TPS2112A, TPS2113A, etc.).
Could anyone help me identify exact part number for U2 ?
Hi and welcome to the community!
The best bet is to write to the support directly at support@polyend.com
They have the schematics and can help you out, perhaps you can even send it in for repair.
Thanks, but i already tried that and didn’t get any response. I can repair it myself. I just need to confirm the part number.
Response can be a little delayed, its 4 days holiday in poland till monday.
If u2 is fried changes are good that the microcontroller is dead too.
You most likely need a replacement board.
Yes, perhaps it is more complicated than I thought. Thank you once again. I will wait until Monday and hope to receive a response.
I‘ve got an answer for you from Polyend. 
It‘s a TPS2113APWR
Crossing my fingers 
, that this is the extent of the damage that you will have to fix 
Thank you !! I hope everything else is still alive (except for the IC8 inverter on a grid board). Were there any additional comments about what to expect in a situation like this (12v instead of 5v), is there a high possibility of permanent damage to the brains of the unit ?
Your welcome 
, no i have not received any additional info that i could relay to you.
But that doesn’t mean i can’t ask for more down the line
If the IC8 is also damaged, it could be an indicator that the overvoltage applied to the TPS2 may have moved beyond itself (eventhough that things has some fault protection features) into whatever else comes after it.
With that in mind, i would say the chances of something else being damaged are probably high. I mean more than double the expected voltage was applied to the poor device 
.
I’m gonna stay positive and hope i’m wrong . Good luck and let us know how it goes
Yeah, the overvoltage moved beyond U2. What happened is after U2 failed, it shorted its pin 8 (IN1) to pin 7 (OUT), allowing 12V to travel downstream. However, after U2, there’s IC4 (a 3.3V voltage regulator), so that main line should be fine. The issue is that pin 7 also connects to another unregulated 5V power line, which likely saw 12V during the overvoltage event. This line splits into two paths: one goes to the Grid Board where IC8 failed and shorted to ground, and the other goes to IC3 (marked NF9 85Z). I have no idea what IC3 actually does, but it appears undamaged.