Gestetner G060 Service Manual page 502

SC TABLE
SC No. Item
SC 386 Development
gamma error K
SC 387 Development
gamma error Y
SC 388 Development
gamma error C
SC 389 Development
gamma error M
SC 390 Development
Bias output error
G570
Definition
• Unsuitable toner
Any of the following
conditions happens three
• Toner supply
consecutive times:
• When the development
• Laser exposure
gamma is out of the
following range:
0.3 ≤ γ ≥ 6.0
• Image transfer
• When Vk is out of the
following range:
-150V ≤ Vk ≥ 150V
• Development gamma
calculation error
• Loose connection
The high voltage supply
• Defective power pack
board (C/B) monitors the
circuit and detects abnormal
• Damaged cable
conditions such as a voltage
leak or no output condition. • Defective
If this happens, the high
voltage supply board sends
• Defective BCU
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.
Related
Possible Cause
SCs
density
mechanism problem
problem
problem
C/B output
development unit
4-20
Troubleshooting Procedure
1. Turn the main switch off and on .
2. Check the process control self-check
result (SP3-975). If the result is not
"1", fix the problem according to the
table in section 4.1.2.
3. Print a full color image by disabling
SC detection (SP5-809-1) and check
if the image quality is OK. If the image
quality is not OK, fix the problem.
Then, enable the SC detection again.
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.
Type
B
B
SM