Vectronics PMT-228 User Manual

Page 12

PMT-228 Instruction Manual

Professor Morse

Self Test
A Self Test is included to perform testing of the display, the buttons, the non-
volatile memory (EEPROM) circuitry and integrity, and the audio circuitry. At
any time, turn off the power to stop the Self Test; however, power should NOT
be turned off during steps involving the non-volatile memory as it could corrupt
the memory.

This test is initialized by:
1. Turn off the power to the Professor Morse.
2. Press

and

hold

only the Select button while turning the power on. The Self

Test starts by displaying the copyright message

"POCKET MORSE CODE

confirming the display is working properly. Release the button before the
message is finished.

3. It then automatically tests the logic line Vpp (shown on the schematic).
4. Each button is automatically tested for shorts to ground.
5. Next, it prompts to press each button in the sequence of Next, Previous and

then Select to test them for proper connections.

6. The non-volatile memory circuitry is then automatically tested. Notice this

step resets the Professor Morse to its factory default settings.

7. The non-volatile memory integrity is automatically tested.
8. When all is okay, a repetitive message

"PASS"

is displayed and sent to the

speaker. However, if something is wrong a repetitive message such as

"EEPROM FAIL"

is sent and displayed.

9. Turn off the power after confirming the audio has good quality.

Failure Message Meanings:

•

VPP

FAIL

Logic line Vpp is not pulled low by a resistor.

•

FAIL

Next button is shorted or improperly connected.

•

FAIL

Previous button is shorted or improperly connected.

•

SELECT

FAIL

Select button is shorted or improperly connected.

•

EEPROM

FAIL

Non-volatile memory circuitry is improperly connected.

•

MEMORY

FAIL

Non-volatile memory is bad.