Xerox Phaser 790 Service Manual page 155

009-326 Rotary Motor RAP
One of the following situations occurred:
• The Rotary Sensor did not detect the Rotary Frame Assy. in the home position within 6
seconds from the signal, Rotary Motor On.
• During a print job, the speed of rotation deviated by more than the allowable amount.
Initial Actions
Ensure that the Rotary Frame Assembly can be rotated manually. Ensure that there are no
obstructions before attempting to test the motor under power.
Procedure
Remove the rear cover. Monitor the Rotary Motor as the power-on selftest executes. The
Developer Frame rotates.
Y N
The Rotary Motor energized.
Y N
There is +24 VDC from J 246 pin 3 to J 246 pin 1 on the Rotary Motor PWB.
Y N
There is +24 VDC from J 33 pin 7 to J 33 pin 8 on the Low Voltage Power
Supply.
Y N
Go to the 001-703 RAP.
Go to Flag 1. Check for an open circuit.
There is +5 VDC from pin 5 to pin 4 on J 245.
Y N
Go to Flag 4. Check for an open circuit. If the wires are OK, replace the MCU
PWB(PL 11.2).
Switch off the power. Connect the DVM from pin 2 to pin 4 on J 245. Switch on the
power. Monitor the voltage as the power-on selftest executes. The voltage is +5
VDC when power is switched on, and drops to less than 1 VDC for approxi-
mately 5 seconds.
Y N
Go to Flag 6. Check for an open circuit or a short circuit to ground. If the wire is
OK, replace the MCU PWB (PL 11.2).
Switch off the power. Connect the DVM from pin 3 to pin 4 on J 245. Switch on the
power. Monitor the voltage as the power-on selftest executes. The voltage is +5
VDC when power is switched on, and drops to between +2 and +3 VDC for
approximately 5 seconds.
Y N
Go to Flag 5. Check for an open circuit or a short circuit to ground. If the wire is
OK, replace the MCU PWB (PL 11.2).
Switch off the power. Connect the DVM from pin 1 to pin 4 on J 245. Switch on the
power. Monitor the voltage as the power-on selftest executes. The voltage is +5
VDC when power is switched on, and drops to less than 1 VDC for approxi-
mately 5 seconds.
A B
Initial Issue
Phaser 790/DocuColor 2006
A B
Y N
Go to Flag 7. Check for an open circuit or a short circuit to ground. If the wire is
OK, replace the MCU PWB (PL 11.2).
Replace the Rotary Motor PWB (PL 10.1). If the problem persists, replace the Rotary
Motor (PL 10.1).
Check the gears on the Rotary Motor (PL 10.1) and the Rotary Frame (PL 6.1) for dam-
age or contamination. Clean, repair, or replace as required.
Remove the Top Cover. Connect the DVM from J 58 pin 2 to frame ground. Rotate the Rotary
Frame until the actuator on the rear of the frame is blocking the Rotary Sensor (PL 7.2). +5
VDC is measured.
Y N
Disconnect P 58 from the Rotary Sensor. There is +5 VDC from J 58 pin 2 on the
Rotary Sensor Harness to frame ground.
Y N
Go to Flag 4. Check for a short circuit to frame ground. If the wire is OK, replace the
MCU PWB (PL 11.2).
Replace the Rotary Sensor (PL 6.1).
Rotate the Rotary Frame until the actuator is no longer blocking the Rotary Sensor. Less than
1 VDC is measured.
Y N
There is +5 VDC from J 58 pin 1 to J 58 pin 3 on the Rotary Sensor.
Y N
Go to Flag 2. Check for an open circuit. If the wires are OK, replace the MCU PWB
(PL 11.2).
There is less than 1 VDC from P58 pin 2 to P58 pin 3.
Y N
Replace the Rotary Sensor (PL 6.1).
Go to Flag 3. Check for an open circuit. If the wire is OK, replace the MCU PWB (PL
11.2).
Check for obstructions between the Base Frame and the Rotary Frame.
Examine the Front and Rear Bearings for the Rotary Frame (PL 6.1) for wear or contamination
that may inhibit rotation. Clean or replace as required.
If the problem persists, replace the Rotary Motor PWB (PL 10.1). If the problem remains unre-
solved, replace the Rotary Motor (PL 10.1).
If the problem remains unresolved, or if erratic or intermittent operation is observed, go to Fig-
ure 1 and check the harnesses shown for loose or damaged connectors. If the wires are OK,
replace the MCU PWB (PL 11.2).
10/00
2-141
Status Indicator RAPs
009-326