WARNING: Invoking some of the tests described below may result in the clearing of data memory or mode settings.

The 3405 has two different self-test functions - a simple display test, and a much more complete keyboard and display test.

Simple Display Test. The simple display self-test for the 3405 is invoked by pressing the Rcl key and then the X (multiply) key. Thirteen and the model number are displayed, similar to this: "¹³ 3405". Pressing the X key again will display "^BLD 68.00". Pressing the X key a third time finally displays the display test pattern, with all segments and mode indicators energized. Repeatedly pressing the X will cycle through the previously described displays. Pressing any other key returns the calculator to normal operation. Press On/C to clear the display register.

Complete Keyboard and Display Test. With the calculator turned off, press and hold the the 0 (zero) key; then press the On/C key. Thirteen, the model number, and a key number are displayed: "¹³ 3405 1-1". The key number of "1-1" indicates that the first key of the first (top) row, the Off key, should be pressed. Continue the keyboard test by pressing On/C key (key number 1-2), then the Tax key (key number 2-1). Continue pressing the keys in order from left to right, top to bottom. When the last key is pressed, "¹³ PASS" is displayed. Press the + (plus) key 8 more times to display 7 different display patterns and finally the all segments and mode indicators test pattern. Press + a ninth time which will again display the all segments and mode indicators test pattern. Press any key to exit the self-test.

The keyboard test can be skipped by pressing the + (plus) key at the beginning of the keyboard test. Then continue through the display test as described above. Alternatively, after pressing +, press any other key (other than Off), to execute an automated display test, which will cycle once through test patterns, and ending with all segments and mode indicators energized. Press any key to exit the self-test.

The keyboard test can be exited at any time (after the Off key is first pressed) by pressing the Off key.

Full Reset of the Calculator. The owners manual documents a way of doing a full reset of the calculator, which restores all mode settings to their factory defaults, and clears the data memories. With the calculator off, press and hold the X (multiply) key, then press the On/C key. The message "^ALL rESEt" (all reset) is momentarily displayed.

WARNING: Invoking the test described below will result in the clearing of data memory.

The 8515 has two different self-test functions - a simple display test, and a much more complicated keyboard and display test.

Simple Display Test. The simple display self-test for the 8515 is invoked by pressing the percent key twice. All segments and indicators in the display are energized. Pressing the percent key again displays "PC 3.01" (a version number?). Pressing percent again puts the number 52 (I have no idea what if any significance this number has) in the display register.

Complete Keyboard and Display Test. The more complicated test is invoked by pressing the reset button, located in the upper right corner of the keyboard, with the tip of a pencil or other pointed tool. Then press the percent key twice to begin the keyboard test. The prompt "test 1-1" is displayed to indicate that the first key in the upper left corner should be pressed. Press the keys in order from left to right, top to bottom. When the last key is pressed, "PASS" is displayed. Press the percent key again to begin the display test. The calculator will automatically step through nine different display patterns in approximately six seconds, ending with all segments and indicators energized. Press any key to exit the self test.

The Calculated Industries web site documents how to access the simple display test for a handful of their calculators.