hp 33s - Keyboard Self Test
The HP 33S has built-in internal,display and keyboard test functions. The keystrokes to access the self-test functions are similar to that for the pioneer models.
The more thorough internal / display / keyboard test is performed by simultaneously pressing the [ C ] key and the [ yx ] key (First row, middle key). Press any key eight times to step through the various display test patterns. A quick copyright notice (‘© HP DEV CO. L. P.’) will be displayed, then ‘KBD 01’ will be displayed to indicate the start of the keyboard test. In order, press each key from left to right on each row, from the top row (starting with the ex key) to the bottom row. Then continue by pressing the keys in the silver chevron below the display in the following order: ENG, cursor-up, MODES, cursor-left, cursor-right, SOLVE, cursor-down, and DISPLAY. The calculator will display ‘33S-OK’ when the keyboard test is successfully completed. If a key is pressed out of order or there is a keyboard problem, an error message will be displayed. The self-test is exited by simultaneously pressing the LN and ON keys.
WARNING: Invoking the tests described below may result in the clearing of data memory, program memory, and mode settings. Also seen the annunciator note below.