heat treat oven

Hi everyone. I recently bought at auction a 1962 heat treat oven (wasn't cheap). Paid $500 for it. It's really heavy and looks very well built. The temp display stopped working and wasn't reliable even while it worked. I'm wondering if I should just replace the thermo couple with a type S or K...

I just got back a quote and after shipping the evenheat KF18 I was looking at would $1000. I'm looking to buy a kiln to heat treat stainless steels and air hardening tool steels. I would like to keep it around $800 and hopefully something in 220v, if possible. I'm in Georgia but I wouldn't mind...