Press and hold the RESET/BYPASS and FUNCTION buttons on power up.
The letter 'd' will appear in the display.
If you press the TAP button, you will enter the diagnostics menu.
Turn the right hand knob/encoder to select a test. The number of the selected test will appear on the display.
Once the desired test is selected (see the table below), press TAP to run the test.
Once the test has completed, the results are displayed as follows:
The number displayed is an error code. A 0 usually means there was no error.
The following table outlines the diagnostics available in the JamMan.
|0||0||Encoder Test||Supposed to test the encoders but I'm not sure how it works|
|1||1||Switch Test||This displays the number for the current button pressed.|
|2||2||SRAM Test||Tests the SRAM associated with the host processor|
|3||3||Lexichip WCS Test||Checks the program memory in the Lexichip|
|4||4||Interrupt Test||Tests the interrupt (precision timing test)|
|5||5||ROM Test||Checks the contents of the ROM.|
|6||6||DRAM Test||Tests the audio RAM. This test takes a while to run. Be patient.|
|7||7||Burn In Loop||This test runs a bunch of the previous tests continually. This is useful for detecting intermittant problems. If a test fails, the loop stops.|
|8||8||ATE Loop||This is used by Lexicon to perform production testing of the JamMan.|
|9||9||Exit Diags||This jumps you back to the main operating system without power cycling the system.|
|10||A||Read Error Log||Lists the previous errors.|
|11||B||MIDI Test||Wrap around test.|
|12||C||MIDI Tool||A scope loop that constantly sends and receives data to the MIDI UART.|
|13||D||Sinewave Generator||Generate a sinewave|
|14||E||Display History||Displays the last tests run (I think)|
|15||F||MIDI Channel||Selects the MIDI channel used by the system in the normal operating mode.|
When the switch test is run, a number is displayed when a front panel or foot switch is pressed. The buttons are mapped as follows:
|0||No button pressed|
|4||RESET/BYP footswitch (ring)|
|5||TAP footswitch (tip)|
|6||FUNCTION footswitch (ring)|
|7||SELECT footswitch (tip)|
Press the RESET/BYPASS and FUNCTION buttons together to exit the test.
This test checks the DRAM which is used to store audio data. Loopers-Delight has a nice page describing this test:
This test writes the string "Does this thing actually work??" followed by 0xAA and 0x55 to the MIDI OUT port and check that each character is received at the MIDI IN port. If an error is detected, a '-' is displayed followed by an error number. The following table describes each error:
|1||The UART transmit buffer is not empty going into the test (should have been emptied on init)|
|2||The UART receive buffer is not empty (at the top of the test loop).|
|3||Sent a byte but the UART is still showing data in its transmit buffer.|
|4||The UART did not receive the byte (receive buffer is empty when it shouldn't be).|
|5||Received data did not match the sent data|
This is a debugging tool that constantly outputs MIDI clock messages.
Disable MIDI Clock
When the FUNCTION button is pressed with the MIDI Tool running, the MIDI clock is disabled on the JamMan (receiving it).
This is a built in little utility that digitally generates a sinewave at the JamMan's output. This is useful for testing the DA converters but can also be handy for testing other gear (using the JamMan as a test tone generator). 1kHz and 440Hz tones are available.
Because there was no place in the normal user interface to allow selection of the system's MIDI channel, we ended up burying it in the diagnostics (ick!). If you want the JamMan to respond to a MIDI channel besides channel 1, you have to go into diagnostics and change it each time the system powers up (huge pain in the ass). Once you've set the channel, you select and execute test 9 which exits you back to the normal operating system with the new MIDI channel.
If at all possible, use the default channel on the JamMan since it won't remember the new channel you select anyway. Most other devices save the MIDI channel.