HP 71B cases and the Black Cloud of Death

[Valentin Albillo]

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Hi,

(10-03-2018 05:28 PM)megarat Wrote:  I recently picked up an HP 71B, [...] The device was shipped in its original case, and when I removed the device, it was covered with a fine soot-like black powder. [...] My guess is that the interiors of these cases are disintegrating [..] Is this a common issue with 71B cases?

Your guess is correct and yes, it's a common issue with 71B cases after several decades, exactly the same thing happened to me (twice). I did the following:

1) Thoroughly cleaned the 71B itself with a blower and a fine brush until no traces of the black powder remained. That includes under each and every key, under the edges of the display's bezel, and within any ports, the batteries, or the card reader bay.

2) Then I washed the case inside and out under a powerful water jet while rubbing the inside with my fingers until the water came out clean.

3) That step completed I left the case submerged in clean mineral water for 24 hours, then used a hair drier to get it perfectly dry.

Now simply shake the case vigorously over a white sheet of paper and inspect it for any further traces of the black powder. If some tiny specs do still appear either shake the case again until no further specs are visible on the sheet or if they're still noticeable repeat from step (2), usually there's no need.

Finally, I didn't use a plastic bag, if there are no further traces of the powder there's simply no need for it. After many years the affected cases have caused no further problems.

V.
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