HP-42S without FIX notation. Very strange.. or not?


Hello guys,
I recently purchased one HP-42S on e. ... Y. I have believed to make a deal... but the calculator returns an error at self-test (FAIL 00004) and not show the numbers in FIX notation but only in SCI and ENG mode. Can somebody tell me something to understand if it can be repaired? Randy, what do you think?
Thank you very much.



Turn it on.

Press and hold down the E+ and XEQ keys. Press and release the ON key. Release the E+ and XEQ keys. You should see "Memory Clear".

If the behavior is not correct after a reset, the only solution would be a replacement logic board :(


Thanks Randy, is exactly what I feared after running the same reset. Sob, :(


Lucky for you, of all the 42s parts to replace, the logic board is the easiest. (...as well as being nearly bomb-proof). As Randy pointed out to me a while ago, the keyboard is the weak link; you still have a bit of luck on your side.
If your wallet can handle it, I would recommend buying another 42s and keep the one you have right now as the replacement keyboard/(LCD).
In 22 years with my 42s, I have replaced the LCD once and relocated the logic board to a new shell twice. (Maybe I am too heavy handed with the keys though).


Hi Dallas,
thank you very much for your valuable advice.

Kinds regards from Italy



No worries. I have to wonder; with all the new calculators that HP is creating with the similar keyboard lay-out as the 42s, if an updated version of the 42s is around the corner.

I still suspect that, similar to the 35s' issues, we will all be clutching our 42s' until we are comfortable with any bugs/idiosyncrasies of a possible new unit.

Possibly Related Threads…
Thread Author Replies Views Last Post
  Strange HP 25 Problem (Repair) Onur Ilkorur 5 2,862 12-06-2013, 05:13 PM
Last Post: Onur Ilkorur
  Strange Battery Icon during updaate of Prime Firmware. Harold A Climer 7 3,485 12-05-2013, 04:40 PM
Last Post: Michael de Estrada
  HP Prime: Converting number to Sci notation and back BruceTTT 1 1,535 11-12-2013, 02:11 AM
Last Post: Phil Wipf
  HP PRIME : strange behavior when trying user key capability Damien 12 3,921 11-03-2013, 11:02 AM
Last Post: Joe Horn
  HP Prime function APP - Strange limitation ! :o( dg1969 2 1,567 10-04-2013, 12:10 PM
Last Post: dg1969
  HP41CX: Strange serial #... Stephan Matthys 1 1,152 09-13-2013, 01:38 PM
Last Post: Stephan Matthys
  SCIOVR and ENGOVR in FIX mode Andrew Nikitin 5 1,807 07-02-2013, 04:46 AM
Last Post: Victor Koechli
  [WP34s] strange behaviour at number entry Dieter 12 3,641 06-06-2013, 05:36 PM
Last Post: Harald
  Strange battery leak Cristian Arezzini 0 946 06-03-2013, 09:49 AM
Last Post: Cristian Arezzini
  Strange video Peter Niessen 9 2,803 04-07-2013, 08:33 AM
Last Post: Csaba Tizedes (Hungary)

Forum Jump: