I haven't had a chance to look for an OS restore yet, but I will. I still plan to image the hard drive, possibly regardless if I find a CD or not.
The more important question is how to deal with the two blown input amplifiers. If the two channels won't calibrate correctly for high impedance, it seems logical to fix the channels, not use them, or use them knowing the measurements will be wrong.
I'm willing to gamble on buying used ones, but spending money on having them replaced with possible fake/junk ones is the larger issue.
Does anyone know which other pieces of equipment these were used in, or any reputable places to buy them?