Parasitic battery drain. Help!

Would really appreciate any advice regarding this frustrating problem. I have an 85 928S that drains the battery over a 2 week period. Battery is new, tests fine and is fully charged. Voltmeter shows .5mA draw at rest. Two weeks takes the battery from fully charged to around 5 volts. It seems as though something is turning on intermittently? I have read other posts and I guess a battery tender would be a solution but I would really like to solve the mystery and correct the problem. Thanks for any/all advice.

Here is a prior post by Brad with instructions for chasing current draws

928mac;335 wrote: The way to check is to disable the passenger side door switch by unplugging it so that you can pull fuses when you get a meter hooked up. set your meter on amps and plug the positive probe at the meter into its 10 amp hole. Disconnect the negative cable and hook the leads between the cable and the battery. read the draw and start pulling fuses until you find the circuit that kills the draw. That will give you a direction to go

That post is absolutely the best way to find a parasitic drain.

I have found that several of my drains were from the rear defrost relay. I have removed all those rear defrost relays from my cars and amazingly have no more battery drains. You might get lucky. YMMV

Thank you both for the quick replies and the good suggestions. I will remove the rear defrost relay immediately and proceed from there with my fingers crossed!

I found that the alarm was drawing quite a bit of current, especially with the hood open - the alarm is connected to the hood switch that also serves the underhood light. Since I tend to have the hood open when i am working on the car I leave a battery tender attached.

Thanks Martin. I will check that, too. Really appreciate all the suggestions. It's great that you all are willing to take the time to help! I'm optimistic now!