HP42S Changing Back to Clear

[DanM]

I've temporarily returned from the land of the lurkers to report that I finally got around to installing the clear HP-42S back which I got from Chuck McCord at HHC 2018 (San Jose) onto my user-model 42.

Take all the shots at me that you would like to regarding doing this to both a mostly-original calculator and an absolutely pristine clear back from the HP-Corvallis way-back machine... it's done already and since you've now seen it, you have to live with the knowledge. :-)

The calculator is my "backup" 42, which I traded something for many years ago. My original 1-owner 42 remains untouched by projects like this. A previous owner of this "backup" both melted off the SN, and melted in their initials or something into it.

I convinced myself that a clear-back 42 is more worthwhile to me than a regular 42 and a clear back. Also I magically changed this one to "Made in USA" from "SINGAPORE".

Enough of that.

I followed Paul Brogger's guidelines to open up the calculator. ( https://www.hpmuseum.org/cgi-sys/cgiwrap...i?read=199 ) The 4 hidden heat stakes troubled me a little bit, but after application of enough force (a lot of force!) they eventually broke off and the back came off. I did move the beeper to the clear back, but I did not move the metal plate, because I wanted to see the calculator PCB. And I'm not quite sure what that does to the operation, but I think I may have trouble passing a RF-interference test now. But operation seems OK. The Clear USA back has slightly different fastening method than the original issue SINGAPORE one, and it appears that it will hold onto the body reasonably well and be reasonably easy to take off if I want to do so.

Thanks, Chuck!