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Homebrew Equipment A place to show, design and discuss the weird and wonderful electronic creations from the hands of individual members. |
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15th Apr 2019, 7:56 pm | #81 |
Hexode
Join Date: Aug 2010
Location: Malvern, Worcestershire, UK.
Posts: 347
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Re: Chinese 1A2 Super Regenerative FM radio kit
My working theory is that cardboard cases and wraps within boxes have a high acidity content and the makers never planned for storage stretching into decades.
Often a new old stock valve is unwrapped to reveal one or more typically corroded pins,the uk material being DUMET from memory and I suspect this green corrosion to be a type of Galvanic corrosion resulting from moist/damp storage conditions but I am not a metallurgist or an electrochemist so cannot be more precise. The later Mullard Cradlepacks could allow the valve pins to contact the possibly damp cardboard top flap above causing said corrosion. Mike |