The resistors and resistor values are different between those two PCBs. I had a few of the older S3 and they were easier to mod because you just had to pencil in 50% of its current Ohm. But the later ones had higher values and you had to pencil in a smaller amount and took alot of play and plug. You need to pencil it in, measure with Ohm meter and plug it in and measure the voltage. Was a big pain.

But you can use regular computer case fans and its CRAZY SILENT at 400Gh/s using 300 Watts. So a good heater.