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HP-28S preservation
08-01-2016, 09:41 PM
Post: #1
HP-28S preservation
I just acquired an HP-28S that is in excellent physical condition, with manuals for < $100.

I just put in new batteries, and found it very difficult to insert the battery cover. After reading very old threads here I'm worried.

It is clear that there is pretty extreme stress on the cover. Is it normal for it to be noticeably pushed out beyond the case? It seems stable, but is not precisely flush with the edge of the case.

Is there anything I should do now, such as tape to relive the stress to prevent breaking later? The Wikipedia image https://en.wikipedia.org/wiki/File:HP_28.jpg shows tape over the case; I don't know if that is prophylactic or holding in the batteries for a trashed case. Someone on an old thread mentioned the unavailability of spare battery covers, but it looks to me like it would be the *case* that would crack form the metal door guides.

Finally, do I need to worry about problems with the hinges? I gather this breaking is fatal to the calculator. It won't see heavy use, and I intend to be careful anyway.

Thanks!
James
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08-01-2016, 10:28 PM
Post: #2
RE: HP-28S preservation
If your goal is preservation, don't put batteries in it, or at least don't put the cover on while it has batteries in it. Aluminum foil and tape are your friend.
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08-02-2016, 11:17 AM
Post: #3
RE: HP-28S preservation
I faintly remember seeing some kind of battery retainer that somebody had fashioned which looked like a bent wire hanger (it wasn't; it looked much nicer) that wrapped around the left side of the body, under the case, and around the outside of the batteries, holding them in without the outward pressure on the battery door slot. Did anything like that ever get produced in (relatively) large numbers?
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08-02-2016, 11:21 AM
Post: #4
RE: HP-28S preservation
I've got one of these battery door replacements for my original 28S which broke this way many years back.

I don't know how many were produced but it is perfect for the task.


Pauli
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08-02-2016, 11:53 AM (This post was last modified: 08-02-2016 11:57 AM by striegel.)
Post: #5
Stainless steel strap for 28S
(08-02-2016 11:17 AM)Dave Britten Wrote:  I faintly remember seeing some kind of battery retainer that somebody had fashioned which looked like a bent wire hanger (it wasn't; it looked much nicer) that wrapped around the left side of the body, under the case, and around the outside of the batteries, holding them in without the outward pressure on the battery door slot. Did anything like that ever get produced in (relatively) large numbers?
Yes, I've seen that.

But I don't know who was responsible for the original. It seems unlikely to have been produced in quantity.
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08-02-2016, 05:10 PM
Post: #6
RE: HP-28S preservation
(08-02-2016 11:53 AM)striegel Wrote:  
(08-02-2016 11:17 AM)Dave Britten Wrote:  I faintly remember seeing some kind of battery retainer that somebody had fashioned which looked like a bent wire hanger (it wasn't; it looked much nicer) that wrapped around the left side of the body, under the case, and around the outside of the batteries, holding them in without the outward pressure on the battery door slot. Did anything like that ever get produced in (relatively) large numbers?
Yes, I've seen that.

But I don't know who was responsible for the original. It seems unlikely to have been produced in quantity.

AJ made these several years ago. Last time this topic came up, he said he didn't have any left over, unfortunately.
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