Grundig Satellit 700 Manual -

The original supercapacitor (C401, 0.1F 5.5V) fails after 20+ years. Symptoms: memory lost when power off for >1 minute.

Search for "Grundig Satellit 700 7001 Service Manual" on Archive.org. Users have uploaded high-resolution scans of the original operator’s manual. These are free to download and print.

The manual explains that the clock runs on an internal capacitor (not a battery in the early versions). If the radio has been off for 3 days, the clock resets. Here is the manual's procedure simplified:

The Grundig Satellit 700 is famous for leaking battery corrosion. The manual’s warnings are critical: