Guys, does someone of you know why there are different labels on the left side of the HP-18C. Here are two different versions I just found during the last month in the bay....
(Sorry, updated the post as there was an error on my side)
Key observation - CHARY - an aftermarket vendor.
BEST!
SlideRule
Chary made overlays for many of the financial machines; probably the earliest was the 12C, however since that model was around so long, it's hard to tell. Overlays for the 12C could have been introduced 5 years before the 18C was launched, or 20+ years after the 18C was discontinued...
But I would guess that the 12C versions were first.
Thanks for sharing that Matthias, I've not seen 18C overlays before.