Gestetner G060, Service Manual

Page: 502 / 1106

SC TABLE
G570 4-20 SM
SC No. Item Definition Possible Cause
Related
SCs
Troubleshooting Procedure Type
SC 386 Development
gamma error K
SC 387 Development
gamma error Y
SC 388 Development
gamma error C
SC 389 Development
gamma error M
Any of the following
conditions happens three
consecutive times:
•
When the development
gamma is out of the
following range:
0.3
≤ γ ≥
6.0
•
When Vk is out of the
following range:
-150V
≤
Vk
≥
150V
•
Development gamma
calculation error
•
Unsuitable toner
density
•
Toner supply
mechanism problem
•
Laser exposure
problem
•
Image transfer
problem
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.
B
SC 390 Development
Bias output error The high voltage supply
board (C/B) monitors the
circuit and 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.
•
Loose connection
•
Defective power pack
C/B output
•
Damaged cable
•
Defective
development unit
•
Defective BCU
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.
B