
3 Perform the keyboard test.
a Press the Keyboard softkey.
A pictorial diagram of the front panel will appear on the display.
b Press each key, and notice that when you press a key a corresponding
block on the display fills in.
c Rotate the knobs (except the intensity) and notice that an arrow
appears on the display that points in the direction you rotate the knob.
d Do all the keys and knobs work?
If yes, Press
Stop two or three times (the display indicates how
many times), then go to step 3. If not, replace the keyboard and
keyboard assembly.
4
Check the output level of the DAC.
a Press the DAC softkey.
b Connect a multimeter to the rear panel CALIBRATOR connector.
The multimeter should read 0 V ±500 µV.
c Press any key to continue.
The multimeter should read 5 V ±10 mV.
d Are the DAC voltages correct?
If yes, press any key to continue. If not, replace the system board.
e Connect a test oscilloscope to the rear-panel CALIBRATOR connector.
f The test oscilloscope should measure :
Vp-p = 900 mV ± 150 mV
Vavg = –450 mV ± 75 mV
Freq = 2.46 kHz ± 100 Hz (54615B/16B)
2.08 kHz ± 100 Hz (54616C)
g Are these readings correct?
If yes, press any key to continue. If not, replace the system board.
Service
Troubleshooting the Oscilloscope
4–42
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