HP 39gs Master Manual page 43

Hard reboot (with loss of memory)
To completely reset the calculator's memory back to factory settings press
1") When doing this, don't press them all at once; hold down the
press the first and then the last screen keys. Release them in the opposite order. Don't release
together - release , then
SK6
accident!
This type of reset will always cause complete loss of data. If you find that the screen fills with garbage, or if
the calculator's in-built diagnostic routine starts to run, then it is just that you have not released them in the
right order. Simply try again.
Calculator Tip
1.
2.
3.
Locked Calculator? Won't turn on? Turns on briefly and then immediately off?
Try the following:
Try a soft reboot using
•
• Try a paperclip in the hole in the back (gently).
Is it possible that the screen is blank because the contrast is turned to extremely light?
•
Try and
ON
Use and
ON
Change the batteries for new ones. Try this more than once because sometimes batteries are dead
•
right off the shelf if they've been in the shop too long. Try replacing the backup battery too. Make
SURE you've put the batteries in right way around. Putting them in reversed may seriously damage
the calculator.
, then . This is deliberately made complex so that it won't happen by
SK1 ON
If your calculator is really thoroughly locked up or won't turn on
then try the procedures listed below this tip.
My past experience with these calculators is that they do tend to
lock up occasionally, particularly if you load aplets and programs
from the web. I usually suggest to my students that they regularly
save their work to a PC and perform a hard reboot about once a
month, reloading the saved work onto the calcu
Pressing by mistake will
ON+SK4
result in the screen shown right.
This is a special diagnostic mode
that can be used by engineers to
test the calculator's components.
There is nothing wrong with
experimenting with it but it is of no use to the average user. To exit,
simply reboot normally by pressing
+ .
ON SK3
to make the screen darker. (Hold down
to lighten the screen.
ON+SK1+SK6
key and, while still holding it down,
ON
lator afterwards.
.
ON+SK3
and press
ON
43
. ( ="screen key
SK1
and
SK1 SK6
repeatedly.)