Gestetner B147 Service Manual page 223

SC No. Item
SC 390 Development The high voltage supply board
Bias output (C/B) monitors the circuit and
error detects abnormal conditions
such as a voltage leak or no
output condition. If this
happens, the high voltage
supply board sends an error
signal (High to Low at CN204-
A18) to the BCU.
The BCU monitors this signal
every 2 ms and generates this
SC code when the error
condition occurs 250
consecutive times.
SC Charge AC: The high voltage supply board
391-01 output error sends the feedback signal
391-01: K (CN228-2 to 5; MCYK). The
391-02: Y BCU monitors these feedback
391-03: M signals every 8 ms. If the
391-04: C average of the sampled data is
not within the control target 20
consecutive times, this SC
code is generated.
SM
Definition Possible Cause
• Loose connection
• Defective power pack
C/B output
• Damaged cable
• Defective
development unit
• Defective BCU
• Power pack
disconnected
• Charge receptacle or
terminal
• Defective PCU bias
input terminal
• Incorrect power pack
B/C output
• Damaged cable
• Defective BCU
• PCU not found
Related
Troubleshooting Procedure
SCs
1. Turn the main switch off and on.
2. Check if the harness and cables are
properly connected.
3. Disconnect the high voltage supply
cables from the bias terminals on the
high voltage supply board C/B.
Measure the DC voltage using a
multi-meter.
• Replace the high voltage supply
board if no voltage is supplied.
4. If the result is OK at step 2, check if
the high voltage supply cable or
development unit is grounded.
• Replace the high voltage supply
cable if it damages.
• Replace the development unit if it
damages.
5. Check the PWM signals are sent to
the high voltage supplied board from
the BCU. Replace the BCU or
harness between the BCU and high
voltage supply board if the voltage is
0.
1. Turn the main switch off and on.
2. Check the connector.
3. Check that the PCU is correctly
installed.
4. Check the PCU charge voltage input
(the spring/conducting shaft) or
replace the PCU.
5. Replace the power pack B/C.
6. Replace the cable.
7. Replace the BCU.
4-21
SC TABLE
Type
D
D
B147/B149/B190