The KN2600 must have a different Sound Memory configuration to the KN7000. The KN7000 Sound Memory retains it's content even through long power-down periods so I believe it uses Flash Memory. I doubt if the KN2600 uses a battery to support its volatile memory content for short power-down periods - it is more likely to use a large value capacitor, which will slowly discharge, resulting in the loss of content after a short time.
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Willum
After silence, that which comes nearest to expressing the inexpressible is Music.
Aldous Huxley
( especially when the music is played on a KN7000....)