HP 71B cases and the Black Cloud of Death

[megarat]

Hey folks, I recently picked up an HP 71B, which is the second one I've owned. The device was shipped in its original case, and when I removed the device, it was covered with a fine soot-like black powder. It didn't seem to cause any harm to the 71B, but the case continues to shed this powder from within, even after shaking and blowing it out. This reminded me that the case of my other 71B had a similar issue, so I dug it out, and sure enough, the interior still sheds small amount of black powder, albeit in a much smaller quantity.

My guess is that the interiors of these cases are disintegrating, and while I plan to blow out their interiors with a shop-vac, I'm wondering if even using these cases is a good idea. Is this a common issue with 71B cases? If so, is there any risk of the particles clogging up the keys/internals? Are there any recommended solutions for alternative cases?

Thanks.

[burkhard]

(10-03-2018 05:28 PM)megarat Wrote:  Hey folks, I recently picked up an HP 71B, which is the second one I've owned. The device was shipped in its original case, and when I removed the device, it was covered with a fine soot-like black powder. It didn't seem to cause any harm to the 71B, but the case continues to shed this powder from within, even after shaking and blowing it out. This reminded me that the case of my other 71B had a similar issue, so I dug it out, and sure enough, the interior still sheds small amount of black powder, albeit in a much smaller quantity.

My guess is that the interiors of these cases are disintegrating, and while I plan to blow out their interiors with a shop-vac, I'm wondering if even using these cases is a good idea. Is this a common issue with 71B cases? If so, is there any risk of the particles clogging up the keys/internals? Are there any recommended solutions for alternative cases?

Thanks.

Yeah, if you only use it occasionally, I think I'd be tempted to keep the 71B inside a plastic bag inside the case rather than risk getting all that dust inside the machine. If I used it frequently, the baggie would get annoying, though. In that case, I'd probably buy another case for daily use, keeping the original for the collection only.

I do have a 71B, but hadn't noticed the black snow. I'll need to pull it out and check!

[Massimo Gnerucci]

(10-03-2018 05:28 PM)megarat Wrote:  Hey folks, I recently picked up an HP 71B, which is the second one I've owned. The device was shipped in its original case, and when I removed the device, it was covered with a fine soot-like black powder. It didn't seem to cause any harm to the 71B, but the case continues to shed this powder from within, even after shaking and blowing it out. This reminded me that the case of my other 71B had a similar issue, so I dug it out, and sure enough, the interior still sheds small amount of black powder, albeit in a much smaller quantity.

My guess is that the interiors of these cases are disintegrating, and while I plan to blow out their interiors with a shop-vac, I'm wondering if even using these cases is a good idea. Is this a common issue with 71B cases? If so, is there any risk of the particles clogging up the keys/internals? Are there any recommended solutions for alternative cases?

Thanks.

It often occurs also with 41C cases (similar, dimensions aside).
You can machine wash it (I did, with one of my 41 cases), low temp of course. This solves the problem once and for all.

[Craig Bladow]

(10-03-2018 05:43 PM)burkhard Wrote:  Yeah, if you only use it occasionally, I think I'd be tempted to keep the 71B inside a plastic bag inside the case rather than risk getting all that dust inside the machine.

This happened to me and I put the 71b in a plastic bag also.

[KeithB]

Since my zipper is broken, too, I just leave it on top of the case. 8^) I like keeping the case around because of the handy pocket for the Quick Reference Guides.

[Gerson W. Barbosa]

It may need only some washing:

Deteriorating pouch (case)

[Valentin Albillo]

.
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.
.

[Harald]

Both my 71Bs have the same problem. It is easily cured, as was already suggested, by puting the case into the washing maschine at low temperature.

[John Keith]

Seems to be a common problem. I have had a couple of camera cases with the same condition. Probably some synthetic material breaking down over time.

[Joe Horn]

The original HP-71B case had a thin layer of polyester foam padding between the leatherette outside and the lining inside. That foam is great when it's new, but over time it stiffens, then turns brittle, and eventually disintegrates into black powder. A similar phenomenon destroys loudspeakers whose cone is suspended in the frame of the speaker by a polyester foam "surround". The benefit of this design is that it's lightweight and cheap and very flexible. The downside is that ozone and time make it fall apart.

[rprosperi]

Using the washing machine works well, but if you have a compressor handy, you can more easily just blow the dust out; hold the case upside-down and using the nozzle, thoroughly 'spray' in all directions. For some reason, blowing the black crud out seems to work much better than using a vacuum cleaner.

Oddly, you may have more of it again (as the padding further breaks down I guess), but only after many (10+) more years of sitting unused. Once you get it all out via wash or blow-out, it's usually fine to store your 71B inside without collecting black crud; no need for a baggie/liner. But if it's just sitting in a collection, check it every few years.

Valentin made an important point - be sure to clean out (blow it out using canned air) the interior of the 4 front ports and the CR slot as well, the crud gets into all the corners.

The early 71B cases with the internal pocket seem to generate more crud than later models.

A very timely topic, as many 71B cases were given away from the HHC prize table, so several folks are about to become familiar with the black crud.

[Hans Holzach]

the foam of my two hp 71b-cases desintegrated as well. when i pressed hard on that black dust with my thumb, it became sticky. now i keep the calculators, which are both in perfect condition, in plastic bags. i did not like the idea of having some kind of tar-like substance on and in the 71s. i threw the cases in the trash.

regards,
hans