Sony DCR-TRV38E Service Manual page 199

Usable cassettes
When the Cassette Memory function does not work
Reinsert a cassette. The gold-plated connector of mini DV cassettes may be dirty or
dusty.
Cleaning gold-plated connector
If the gold-plated connector on the cassette is dirty or dusty, the remaining tape
indicator sometimes does not appear correctly, and you may not be able to operate
functions using Cassette Memory.
Clean up the gold-plated connector with a cotton-wool swab, about every 10 times
ejection of a cassette. [b]
[b]
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