Having tried an LM317 with small heatsink, in place of the failed U6 (1.2V regulator) which quickly became seriously hot (90+ degrees C). I looked at alternatives.

Most FPGA boards appear to use switching regulators, there are some very low cost ones on eBay using an LM2596 Buck Converter. The one I bought is eBay item 283630220212. I mounted it half an inch above the board using a couple of short stiff copper wires. Beware they come set for max output Voltage, test it off board first with a bench power supply. The minimum Voltage from mine is 1.22V (pot turned fully anti clockwise.

Running 7 Skimmer “slices”, the LM2596 reads 47 deg C on my ir thermometer. The air temperature in the shack is 28C. That is with the board in open air, but even in the QS1R case it shouldn’t be an issue.

I cannot detect any QRM from the board, either using SDRMAX V to listen, without an antenna, or with an antenna, nor can I detect any noises from it on the shack radios when “Skimming”.

Looks like a cheap and simple fix.

73 Dave, G4AON