Electro 35 Battery Drain after POD replacement

Not sure what's going on - replaced the POD and light seals, everything worked great. Took it out yesterday for its first day of shooting, and today the battery test doesn't go on, nor the over/under. Any ideas on what to check?

Are you turning on the lock switch? I think I read that this 'turns off' the meter, even though you would suspect that it isn't running when you're not pressing down the shutter. But if you aren't locking it, that would be the first thing to change.