[Mark1960]

I’ve read a few times in different fora that one method of recovering data from an eprom that has started to lose its memory due to old age is to vary the supply voltage. If this is correct then reading the eprom at 3v3 might not mean it would work correctly in its original 5v system.

Also if you read an eprom and find it doesn’t match the required content, how do you know if its because you read it at 3v3 instead of at 5v.

For fault finding its probably better to read devices as close to the correct spec as possible.