OM-1/1N meter needle will move without batteries. It is a totally mechanical movement, controlled by strings and pulleys. At asa 400 (which is a cam position) the needle will center at (approx.) 1/2 second at f1.8. No battery, meter switched off etc. If you meter does drop to the bottom when you turn the switch off, then at least the coil is working. Yours does sound like it's 6-8 stops off. Could be corroded battery wire, bad meter switch, bad meter ground or ....bad meter coil. Even with bad coil though, the needle can center, it is not to be confused with a correct meter reading. I can overhaul that for you if you're interested. John