So I decided to build Grant Searle's simple 6502 machine, and started with the oscillator. Rather than getting a clean 1.8MHz clock, I had a not-quite-square wave that was somewhere between 40 - 50MHz, depending on tongue angle, regardless of load (into a 6502's clock input) or termination (tried 100 ohm and 10k pull up and pull down). I figured my crystal was a dud, so I dropped in a 32kHz watch crystal soldered onto some header pins and still had a 40 - 50MHz not-quite-square wave with a 32kHz modulation. Assuming I seriously screwed up, I began pulling out components until I got to the point where there was a resistor across the input and output of two gates. I no longer had a 40-50MHz not-quite-square wave. I had a 75 - 100MHz sine wave. I chalked it up to gremlins in the cheap breadboards I had at my disposal.
A few weeks go by. After watching eevblog #568, the thought hit me... what would happen if I soldered resistors directly across the leads and held the thing in the air? A few more weeks go by. I finally gave it a shot tonight. Grabbed a few 100 ohm 1206s, soldered them across the appropriate leads and sure enough, I have a 75 - 100MHz sine wave.
What is going on here? Is this expected? A bad 74hct04? Or most likely, did I miss some basic fundamentals?
edit: the oscillator originally started out as the one from
http://searle.hostei.com/grant/6502/Simple6502.html