Well, it's vintage, anyway. I took out my HP 5307A counter yesterday and discovered that it has decided to go insane. While the CHECK function correctly registers a display of 1's as it should, external frequency measurements are complete nonsense. 60 Hz, for example, shows up as 112 Hz. A quick check of power supply voltages shows they're all within about 5% of nominal value; there doesn't seem to be more than a couple of mv. of ripple. The 10 MHz oscillator is right at 10 MHz. Any ideas or suggestions? It'd be nice to have "old reliable" back again. Cheers, Chuck