Is it a mistake, or are they interchangeable? (Algemeen)

door gertjanrhe , Gooi, 03.04.2022, 12:55 (965 dagen geleden) @ edison

can be it was used at a repair shop and by mistake the wrong box was used to restore the tube after a test was done.

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De techniek was in de jaren 40 veel verder dan menigeen zich bewust is