
To check the Low Voltage Power Supply
1 Disconnect the power cord, then set the oscilloscope on its side.
2 Connect the negative lead of the multimeter to a ground point on the
oscilloscope. Connect the power cord and turn on the oscilloscope.
3 Measure the power supply voltages at E10 through E15 on the system
board.
Power Supply Voltage Tolerances
Supply Voltage Tolerance
+5.1 V ±153 mV (+4.947 V to +5.253 V)
–5.25 V ±158 mV (–5.092 V to –5.408 V)
+15.75 V +1.260 V, –787 mV (+14.963 V to +17.010 V)
− 15.75 V ±787 mV (−14.963 V to −16.537V)
Low Voltage Power Supply voltage test points
If the +5.1 V measurement is out of tolerance, adjust the +5.1 V adjustment
on the power supply; if the –5.25 V measurement is out of tolerance, adjust
the –5.25 V adjustment on the power supply (see figure 4-2). The ±15.75 V
supplies are not adjustable and are dependent upon the +5.1 V supply.
Blown fuse
If the fuse is blown in the power supply, the power supply is defective. Replace
the power supply.
Figure 4-7
Service
Troubleshooting the Oscilloscope
4–40
Comentários a estes Manuais