Wacky Minolta Autometer IV?

I was testing a "new" Konica Autoreflex T3 camera's light meter yesterday against my Minolta Autometer IV. Nothing too scientific here - just reading the bright spot on my computer monitor. Well, the old camera said use f5.6 while the autometer said 2.8. Curious, I picked up my Canon AE-1 program and it too said use 5.6. So I took a digital image at the same setting, f 5.6, and it looked to be dead on accurate.

Is the Minolta meter out of whack, or is this a bad test for it? It had a fresh battery.

computer monitors do not provide a constant light source. The screen flickers. Some meters respond so fast that they may take the reading during the dimmer part of the screens redraw. Try reading outdoors under natural light, pointing the meters at a neutral colored thing like a grey wall or white wall. Colored objects will often read different with different meters due to differences in the spectral response of the meter cells.