Haven't used this meter in a while so decided to turn it on. The display comes on and I can change the Time/ASA numbers. However, instead of an f-stop it only displays "E" -- even outside. Is the battery low or is the meter kaput?
Try a new battery. Batteries deplete themselves over time, and you risk leakage. If it still doesn't work, you'll likely need a repair, although with the age of the meter, it's unlikely there are parts available.
the first rule of relative long-term "storage"* on any battery powered device is remove battery.
- power drain prevention
- contact corrosion prevention
