HP 19C Spring loaded Thingy?

[[kby]]

(06-16-2020 01:28 PM)rprosperi Wrote:  …I don't think my unit is a frankencalc (e.g. with base from earlier unit) as the hook mounting seems to affect both case halves…

This isn’t definitive. The plastic molding of the lower case is not affected as the pivot the security tab attaches to in the case is the pillar that the screw on that side enters from the lower case (under the rubber foot) to hold the lower and upper cases together. This is not altered. The upper case, on the other hand, is modified to include the small cutout for the security tab. Unfortunately, the serial number is on the lower case half (which contains the tab, but it can be removed; see below) and the actual case mod is on the upper case half.

Now, to make matters more complicated, I’ve found the method by which the actual security tab and its associated spring (which, in my very limited experience of only two machines, are identical in all cases) is not always the same.The actual security tab and its spring fits loosely on the post (so that it can freely rotate), but I have seen this secured vertically on the post by (1) a very tightly friction-fit washer or (2) a proper, but not tightly fitting brass eyelet (vaguely funnel shaped; if you can image a funnel in which the wider top part is flat rather than sloped, so in profile it looks kind of “T” shaped) that is high enough to keep the tab properly aligned when the case is fit together. The second case is very easy to transplant between lower cases. The first is possible as well, but is much riskier and seems to leave scratches on the post if removed or added (but maybe there’s a clever way to do it which won’t).

In my anecdotal observational experience, “S” models seem more likely to have the tab than “A” models, but it is not 100% on either side and may be just a fluke of small numbers of cases.

[Edit: I've been thinking again and realizing my description of the attachments wasn't quite right. There is a washer involved probably in both cases, but the one that I thought was friction fit was described wrong. It wasn't the washer that was tightly friction fit, it was a very thick (maybe ~0.5–1mm?) external C-clip that kept things held down. I can't remember for sure (and I don't want to take apart the machine) whether the other implementation had a washer, but it is likely that it did.]