MX-1800N (serv.man16). Section 8 - Self Diagnostics Trouble Codes - Sharp Copying Equipment Service Manual (repair manual). Page 22

MX-1800N  SELF DIAG AND TROUBLE CODE  8 – 22

 

 

 

 

 

 

 

 

 

 

Trouble content

It is judged that the LSU polygon motor lock signal 
is not outputted, and the lock signal is checked 
after 7 sec from starting rotation of the polygon 
motor and it is judged that the polygon motor does 
not rotate properly.

Section

LSU

Case 1

Cause

Disconnection of the LSU connector or the LSU 
inside harness, or breakage

Check and 
remedy

Check connection of the harness and the 
connector.
If the trouble cannot be removed, replace the 
LSUcnt PWB or the LSU.

Case 2

Cause

Polygon motor trouble, LSU PWB trouble

Check and 
remedy

Use SIM61-1 to check the operation of the polygon 
motor.
If the trouble cannot be removed, replace the 
LSUcnt PWB or the LSU.

Trouble content

No full wave signal is detected.

Section

PCU

Case 1

Cause

Harness trouble

Check and 
remedy

Check connection of the harness and the 
connector.

Case 2

Cause

Power unit trouble

Check and 
remedy

Replace the power unit.

Case 3

Cause

PCU PWB trouble

Check and 
remedy

Replace the PCU PWB.

Trouble content

The full wave signal is judged as frequency 
abnormality. (The detection frequency is judged as 
65Hz or above or 45Hz or less.)

Section

PCU

Case 1

Cause

Harness trouble

Check and 
remedy

Check the harness and the connector connection.

Case 2

Cause

Power unit trouble

Check and 
remedy

Replace the power unit.

Case 3

Cause

PCU PWB trouble

Check and 
remedy

Replace the PCU PWB.

Trouble content

Communication establishment error/Framing/
Parity/Protocol error

Section

MFP

Case 1

Cause

Connector connection trouble between the mother 
board PWB and the MFPcnt PWB.
MFPcnt PWB mother board connector pin 
breakage

Check and 
remedy

Check the connector connection between the 
mother board PWB and the MFPcnt PWB. Check 
grounding of the machine. 

Case 2

Cause

Mother PWB trouble

Check and 
remedy

Replace the mother PWB.

Case 3

Cause

Mother PWB jumper error

Check and 
remedy

Set the mother PWB jumper to the Default side.

Trouble content

The personal counter is not installed.

Section

MFP

Case 1

Cause

The personal counter is not installed.

Check and 
remedy

Install the personal counter.

Trouble content

Backup SRAM battery voltage fall

Section

MFP

Case 1

Cause

1)

Battery life

2)

Battery circuit abnormality

Check and 
remedy

Check that the battery voltage is about 2.5V or 
above.

Trouble content

EEPROM device read/write error

Section

MFP

Case 1

Cause

EEPROM device trouble

Check and 
remedy

Replace the EEPROM device.

Case 2

Cause

EEPROM device contact failure

Check and 
remedy

Check that EEPROM device is properly inserted.

Case 3

Cause

Device access error due to electrical noises

Check and 
remedy

Replace the MFPcnt PWB.

Trouble content

A HDD or Flash memory for user authentication 
different from that used before turn off the power is 
installed.

Section

MFP

Case 1

Cause

HDD replacement or Flash memory replacement

Check and 
remedy

Initialize the authentication information with SIM16, 
and import the backup data (exported data) if any.

Trouble content

User index information (basic data of user 
authentication) check sum error on the SRAM

Section

MFP

Case 1

Cause

1)

SRAM trouble

2)

Hang-up of the control circuit due to electrical 
noises

3)

MFPcnt PWB SRAM access circuit trouble

Check and 
remedy

Use SIM16 to cancel U2 trouble.

Trouble content

Counter information check sum error on the 
EEPROM

Section

MFP

Case 1

Cause

1)

EEPROM device trouble

2)

EEPROM device contact failure

3)

Device access error due to electrical noises

Check and 
remedy

Use SIM16 to cancel U2 trouble.