Roland AC-90 Service Notes page 17

Jul. 2007
6. Signal-level Test (Testing in PCB State)
The Test mode is used in the signal-level inspection testing.
1. Foot-switch Connections
Connect two FS-5U foot switches to [Foot SW 1] using a PCS-31 foot-
switch cable.
The settings and connections for the FS-5U foot switch are as shown
below.
• Set the [POLARITY] switch on the FS-5U foot switches to the setting
opposite that of the jack.
• Foot-switch connection cable connection
The PCS-31 foot-switch connection cable is a stereo to standard x 2
adapter cable.
On the standard plug, "white" is [TIP] and "red" is [RING].
Connect the standard plugs to the respective FS-5U foot switches.
You can connect the white and red sides to either FS-5U unit.
2. Panel Settings
[PICKUP] switch:PIEZO
[SELECT] switch:LINE
All other switches:OFF
All VR (volume) controls:MIN
* The unit will not enter the Test mode unless the settings described above are
made correctly.
3. Entering the Test Mode
With the settings in the 2's state, hold the [TIP] (white) foot switch hold
down and switch on the power.
• Depressing the foot switch twice within 4 seconds after powerup makes
the unit enter the Test mode.
• Immediately after the unit enters the Test mode, the following LEDs flash
several times.
GUITAR channel [CHORUS] LED
MIC/LINE channel [CHORUS] LED
[ANTI-FEEDBACK] LED
[MUTE] LED
• After that, the [ANTI-FEEDBACK] and [MUTE] LEDs light up as a
display to identify the AC-90.
* The LEDs are used to confirm whether inspection tests are passed or failed, so
verify that the following LEDs are able to flash.
GUITAR channel [CHORUS] LED
MIC/LINE channel [CHORUS] LED
[ANTI-FEEDBACK] LED
[MUTE] LED
• When holding down [TIP] (white) FOOOT SWITCH once, the LEDs start
toflash to indicate its software version.
During indicating the version, when holding down [RING](red) foot
switchonce, GUITAR[CHORUS] LEDs light up, and then the unit
entersSingal-level Test Mode.
4. Oscillator Signal Levels
During GUITAR channel input: (mono phones input)
1 kHz sine wave of -10 dBu
During MIC/LINE channel input:(using DI-1 )
1 kHz sine wave of -10.6 dBu
• DI-1 use: Signal-level adjustment at balance input and DI-1 input
• DI-1 settings: POWER=AUTO, ATT = 0 dB, ø = NOR, GND = NOR
* 0 dBu = 0.775 Vrms
5. AC-90 Settings
• Panel Settings
[PICKUP] switch: PIEZO
[SELECT] switch: LINE
All other switches: OFF
MASTER volume: MAX
All other volume knobs: MIN
• Verify that the specified levels are output at the points indicated on the
"Circuit Diagram (Main Board: Analog, XLR Board)" (p. 26).
• When you have finished inspection at all test point, switch off the power.
This completes the inspection-test procedure.
AC-90
17