HP 40gs Self Test
If the display can be turned on, but the calculator does not seem to be operating properly, do the following diagnostic self test. WARNING: Invoking the test described below may result in the clearing of data memory, program memory, and mode settings of your HP 40 gs.
Automatic Continuous HP 40 gs Self Test
Hold down the [On] key, then press the 5th softkey (top row keys just below the screen)at the same time.
This will perform a continuous internal / display the test will cycle through CPU, display, IROM, and IRAM tests. ‘Copyright message’ is briefly displayed before starting over.
This cycling test is cancelled by simultaneously pressing the [ON] key and the 3th softkey (the third key on the top row).
Manual HP 40 gs Self Test
Individual tests can be performed by simultaneously pressing the ON key and the 4th softkey (the fourth key on the top row).
The HP 40 gs will display the Version Number and Build Number. Followed by the menu options to individual test: 1. LCD; 2. KEY; 3. FLASH; 4. SRAM; 5. USB; 6. RS 232; 7. BUZZER; A. AUTOTEST.
Simultaneously press ON and 3th softkey (the third key on the top row) to exit the individual test mode.