Xerox 8850 Service Manual page 42

LL-24 Developer Fault RAP
This fault will occur when an over-current condition is detected on the Developer output. The
fault is to protect the media path from massive contamination from developer beads. If the
Developer voltage drops too low (less than -100 VDC), the developer beads will be pulled out
of the Developer Housing into the BTR, Detack Corotron, media path, etc. Also scratches,
dings, or other damage to the photoreceptor exposing the metal substrate will cause this fault.
The software is more sensitive to this fault, and if there is a xerographic fault, the LL-24 fault
code will often be declared before the LL-21 or LL-22 fault codes.
Initial Actions
• Check that the Printer firmware is 02.01.51-16 or higher is installed. If not upgrade the
Firmware to the latest version.
• Check that the Tag 6 High Voltage Power Supply is installed.
• Ensure the Developer Housing is fully seated and pushed fully towards the drive side.
• Check that the Developer seals are installed and in good condition. If not, install the
Developer Seal kit.
NOTE: Refer to BSD 9.8 and BSD 9.3 when using this RAP.
Procedure
Run [0921-1] and check the developer bias at the Developer Housing. The bias voltage is
approximately -240+/- 20 VDC.
Y N
Refer to GP 1 and check the High Voltage Power Supply DEV V. The voltage output is
present.
Y N
Check the Developer Bias On signal (A25P/J1-10) is low (less than 1.5 VDC). The
Developer Bias On is less than 1.5 VDC.
Y N
Check the wiring between A25 P/J1-10 and A2 P/J605-11 on the Main PWB
(A3). If the wiring is okay, replace the Main PWB (A3)
Replace the High Voltage Power Supply
Check the voltage between 24V RET J7 and A25P1/J1-15. The voltage is Low, less
than 1.5 VDC.
Y N
Replace the High Voltage Power Supply
Check the wiring from the HVPS to the Developer Housing for pinch points that might
cause an open or short circuit.
Look for an excessive amount of developer material (beads) in the Developer area, media
path, and corotrons.
Remove the Developer Housing and clean any contamination on the Housing and in the area
of the Housing.
Clean the Registration Feed Baffle.
Clean the BTR and BTR channel.
Status Indicator RAPs
LL-24
(PL 1.1)
(PL 1.3).
(PL 1.3).
Clean the Detack Corotron and channel. Check the corotron for bent or damaged pins and end
block for arcing damage (scorching) damage.
If the problem persists, escalate the call.
03/2003
2-8 8850/ 510DP