The meter is a Fluke 73 series II -- nothing extraordinary there. According to the service manual for the meter, the error is 0.4% +/- one digit for DC voltage, and 2% +/- 2 digits for AC voltage from 45 Hz to 500 Hz (lowest range) or 1 kHz (other ranges). It's a 3 1/2 digit meter.
I'm not suggesting that the meter is exceptionally accurate, but rather that my oscilloscope is not, and in my experience (and to my understanding) oscilloscopes in general are likewise limited in their accuracy. You may observe I said nothing about the accuracy of your oscilloscope in particular. The 7704A is an old-school analog mainframe scope with plug-in amplifiers and timebases, and according to its service manual should be calibrated (the mainframe) to approximately 1% for the vertical amplifiers. I don't have the actual specifications on its accuracy. I do know that I would struggle to observe out much better than 2% error from the graticule on the CRT. In its current state, it's nowhere near properly calibrated, but that's immaterial here...I'm assuming it were operating in top-notch form. (Being an older analog scope, there are no nifty aids like cursors with readouts. It does have on-screen display of the vertical and horizontal gain settings, generated with some analog magic.)
Many DSOs are based around 8-bit A/D converters, which sets an absolute limit to their accuracy of about 0.5% at full scale simply due to quantization errors. High-resolution DSOs may indeed be more accurate than run-of-the-mill decent multimeters, assuming the rest of their signal chain is up to snuff. (What's the precision of a typical 10x scope probe? A basic Tektronix passive 10x probe (TPP0200) lists the input impedance +/- 1.5%....
Oscilloscopes are, of course, very versatile and useful tools, and can measure and show things that are absolutely impossible to do with a multimeter. But, by and large, they are not really suited for highly precise measurements.
I did just dusted off my scope and plugged it in and turned it on for the first time in awhile, and it promptly blew the line input fuse. :( I guess I have some troubleshooting to do in my copious free time.
