HP 48g Graphing Calculator - Manual (Page 446)

6. If the problem still exists, perform a memory reset. You may lose
data during a memory reset, so do this only if you must:
a. Press and hold IHD-
b. Press and hold the “A” and “F” keys (the keys with A and F
next to them).
c. Release all three keys.
The calculator will beep and display the message Try To RecoMer
Memory? at the top of the display. Press YES to recover as
much memory as possible.
If these steps fail to restore operation, the calculator requires service.
If the calculator responds to keystrokes, but you suspect it’s
malfunctioning;
1. Run the self-test described in the next section.
■ If the calculator fails the self-test, it requires service.
■ If the calculator passes the self-test, you may have made a
mistake operating the calculator. Reread appropriate portions of
the manual and check “Answers to Common Questions” on page
A-1.
2. Contact the Calculator Support department. The address and
phone number are listed on the inside back cover.
Self-Test
^ If the display turns on, but the calculator does not seem to be
operating properly, run the diagnostic self-test.
To run the self-test:
1. Turn on the calculator.
2. Press and hold (ON ).
3. Press and release the “E” key (the key with E next to it).
4. Release fON).
The diagnostic self-test tests the internal ROM and RAM,
and generates various patterns in the displajc The test repeats
continuously until you perform a system halt.
A-10 Support, Batteries, and Service