Stereo drains battery when off

[djnolan]

Reposted to the technical forum sorry folks
I have tried two different after-market stereos in this 944s and both drain the battery within a few days. Both have been wired per the instructions with the yellow memory wire to the radio amp fuse (fuse 39) and the red power lead to accessory power for the radio (fuse ??) Both of these stereos are plain old four channel 45W units.

I put an analog ammeter across the battery to verify the current drain (wildly swinging between 200 - 800 ma) and when you pop the radio amp fuse (#39) the drain goes way down (60ma) and the battery holds a charge for weeks. Concluded it was the radio. The rate of drain is enough to completely discharge the battery in two days or less, so something must be done or the battery will soon be ruined.

So i tried wiring both radio leads (yellow and red) to the accessory power wire and the radio comes on when the key is on and works fine, doesn't drain the battery when the car is off, but the radio doesn't keep preset memory or remember the last station it was tuned to. Not a great solution but at least I have a radio now and my car starts in the morning.

So I sniffed around on a few car audio sites and found a few clues . Maybe some dip-switches need to be set differently on the radio to prevent this drain. Maybe the faceplate needs to be removed when the car is parked to prevent this drain.

So I go to download a manual for the flippin radio (Aiwa CDC MP3YU) to see if it provides any help. The site wants me to download all of this fancy pdf reader software and sign up with my CC. I didn't go far, as I don't need to be disinfecting my computer this weekend! The site is 3rd party and Aiwa doesn't even appear to maintain a web site.

So somebody has seen this problem before beside me and the previous owner, I hope.