if found out that the wire wasnt good, so i replaced it. But the 4 hashbord heat the wire melt, so i found another hashboard and everything is fine. What is the second mode?
Where did you get a replacement wire? It will melt if you are using very thin wire or cables.
I'm a bit confused do you have stocks of hashboard as a replacement?
What exactly second mode are you talking about?
A mostly short circuit is the reason why wire and cables are melting without a multitester we do not know if the hashboard is shorted or not.
If I were you hire a professional Hashboard technician to repair your hashboard you can check this
https://www.zeusbtc.com/ASIC-Miner-Repair/You can also get an idea of how to repair hashboard at the bottom of that page.