AL-840 (serv.man9). AL800 840 Service Manual-Troubleshooting - Sharp Copying Equipment Service Manual (repair manual). Page 15

No

C16

CASE 2

No

TROUBLE POSITION
CAUSE

Cabinet (operation unit) open/close detection switch actuator does not operate while the cabinet is
opened/closed.
1) Cabinet (operation unit) open/close trouble

REMEDY

(Check)
1) Cabinet (Operation unit)

(Remedy)
1) Cabinet (operation unit) replacement

(After work)

NOTE

SELF DIAG CODE MESSAGE

CH

No

C17

PHENOMENON

DISPLAY

CODE

MAIN CODE

CH

SUB CODE

LAMP

"CH" blink

TITLE

Developer cartridge detection trouble

DETAIL

1) Toner density sensor malfunction 
2) Toner density sensor signal recognition error

SECTION

Developer cartridge

ITEM

TYPE (MODE)

User

YES

Warning

YES

Service

YES

Trouble

YES

Other

Other

OPERATION MODE

All modes

Machine operation when the
message is displayed

Stop

NOTE

BASIC CAUSE 1

Toner density sensor signal level recognition error

CASE 1

No

TROUBLE POSITION
CAUSE

Toner density sensor signal recognition error
1) Toner density sensor trouble
2) Toner density sensor signal input circuit trouble

REMEDY

(Check)
1) Toner density sensor
2) Toner density sensor signal input circuit 

(Remedy)
1) Toner density sensor replacement
2) PCU PWB Replacement

(After work)
1) When the MCU PWB is replaced, perform simulations to input various set values and

adjustment values.

NOTE

SELF DIAG CODE MESSAGE

E1

No

C18

PHENOMENON

DISPLAY

CODE

MAIN CODE

P

SUB CODE

LAMP

"P" blink

TITLE

Paper misfeed

DETAIL

1) Paper entry detection (PIN) malfunction 
2) Paper entry detector (PIN) signal recognition error
3) Paper feed roller abnormal rotation

SECTION

Fusing, paper exit

ITEM

TYPE (MODE)

User

YES

Warning

YES

Service

YES

Trouble

YES

Other

Other

OPERATION MODE

All modes

Machine operation when the
message is displayed

Stop

NOTE

BASIC CAUSE 1

1) Paper entry detector (PIN) signal recognition error
2) Paper feed roller does not feed paper.

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