I have a Fluke 8050A bench multimeter. All ranges are absolutely spot-on except the AC ones, which are pitiful. I tried to perform the calibration procedure in the service manual, but among the test levels it wants, it calls for 19V 10kHz and 100V 10kHz. I used approx. 18V for the lower one (my function generator wouldn't go any higher), and I have absolutely no way to get 100VAC at such a frequency. Did my best to adjust that range using mains voltage but it doesn't seem to have done much good. The two trimmers affect each other, so not being able to properly adjust the higher range has an impact on the lower one as well - and they're trim capacitors, not resistors, so the frequency does indeed make a difference. Does anyone have any ideas, short of building a nearly ±150V amplifier, to get the AC ranges at least decently usable?