Heating failure #1, problem solved for now

My replicator 1 dual ctc clone had a number of problems from day 1, missing screws, and SD card, after tightening up all screws, and checking the power supply was set to UK voltage, I switched it on, there was a loud bang, the power supply had blown, after checking the wiring, I noticed that the mains wires were connected wrong, the supplier sent a new power supply, and supplied a link to the software. After all that, it printed well for about a month, then came the "Heater failure #1 error", I checked all the connections, they were all ok, after several emails to supplier, they sent me some new k-type thermocouples, this did not solve the problem, I replaced the 24v 40w heaters also, but the error was still there, more emails to supplier, and more of the same replies from them asking for photo of error, I decided to investigate the Main board. I noticed after the thermocouple socket was 2 MAX6675 temperature chips, these must be where the problem lies, after many more emails to the supplier, and not getting anywhere, I decided to replace the MAX6675 chips, once I put the board back in, and connected up the wires, the printer now works fine. I now have enough knowledge to maintain the printer, funny though, I wanted to buy one, and not build one.