OK, you have a new battery.
First things first...does the charging system works properly? You are at the mileage where the brushes on the voltage regulator may be worn out. You will find this on the back of the alternator, mounted with two screws.

Beyond that, ther could be lots of things to drain the battery, from the antenna motor to a relay that stays energized. You need a multimeter or test light to try and find it.

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