Front Panel Pots - Lexicon MPX G2 Service Manual

MPX G2 Service Manual
Encoder:
The Encoder Test verifies the operation of the Encoder including direction and its 36 positions. It's designed
so if there is a bad position on the Encoder, the display will never indicate a "Passed" message. This is
achieved by having the accumulator value reset to 0 if a switch position is bad or if the Encoder is turned in
the opposite direction during the test. Therefore, the accumulator will never see the expected value of 36 so
the program wouldn't be able to perform the next task.
When the Encoder is being tested, the top half of the display will indicate the Encoder direction. The test
requires the CW direction to be tested first.
When the ENCODER is being turned CW the display reads:
Accumulator Value -------------5
In this example, the Encoder was turned 5 positions CW.
After the ENCODER is turn 1 revolution CW (covering all 36 positions) the display reads:
The bottom half of the display (CCW Test) indicates the CCW test is ready to be executed. When the
ENCODER is being turned CCW, the display will read
Accumulator Value -----------3
In this example, the Encoder was turned 3 positions CCW.
After the ENCODER is turn 1 revolution CCW (covering all 36 positions) the display will then read:
Pressing and holding the NO< button for about ½ second will exit the test.

Front Panel Pots

This test verifies the functionality of the Low, Mid, High and Output pots on the Front Panel of the MPX G2.
They are connected to Digipots (digitally read potentiometers) on the main board. Therefore, they are read
digitally. The Low pot is connected to U42, the Mid pot is connected to U44, the High pot is connected to
U43 and the Output pot is connected to U3.
Note: Prior to running this test, turn the pots fully CW.
At the Functions Tests menu turn the Encoder until the display reads the following:
Next press the STORE button and release, the display will read the following approximately 2 seconds after
the release of the STORE button.
5-8
Right Insert
Removed
Encoder <> CW
CW Test
Encoder <> CW
0 CCW Test
Encoder <> CCW
CCW Test
Encoder <> CCW
Encoder Passed
Diags: Tests
< Pot
Tone Pot test
Turn a pot