No worries. I have found over the years that all miners break to fast as all of them are run too fast.
I like bitmain because I can buy this controller.
https://epicblockchain.io/product/and down clock them a fraction.
It always seems to make the miner last longer.
some modified t21's
1 board pulled
and the remaining 2 boards clocked to 48th vs 63th.
I will turn 2 t21s into 3 modded t21s
190+190 = 380 hash
down to
96+96+96 = 288 hash
fans are quieter
and power is
3400+3400 = 6800 into 1800+1800+1800 = 5400
