I have 2 HP-42S calculators with different displays. The older one (by serial number) has a display bezel which is nearly flush with the glass. The newer unit has a bezel which meets the glass at about a 60 degree angle. The newer display seems more readable to me. Both were manufactured in Singapore.
Does anyone know the serial number where the newer displays began? This would be helpful to me as I am considering purchase of an additional unit.
best regards,
Don
Don --
I can narrow it down for you a little. My eBay-purchased 42S is a "flat bezel" with serial #2939S33496 (late 1989).
Several of my co-workers have employer-provided "curved bezel" units with serial #'s from late 1990.
Those units exhibit the minor permutation/combination bug mentioned in MoHPC. My older unit does not. I believe that the ROM revision coincided with the changes to the face.
The new version started somewhere at the end of 30xxxx or at the beginning of the 31xxxx.... (have seen both variants with serials starting with 30, have never seen one with the old with a serial of 31 or above)
Best regards,
Erik Ehrling