HP Laserjet 4 Manual

Jam Location Checks and Action Required
Input Area Jams
(Sensed by PS1.)1. Check that the Transfer Roller is fully seated and shows no
sign of wear.
2. Check that the Toner Cartridge is fully seated.
3. Check that the cassettes are not overfull and the media is
loaded correctly.
4. Ensure that the media meets specs. (media is not too
smooth or rough),  and it has been stored properly.
5. Ensure that the paper tray is fully seated  (especially if
printing from the Lower Cassette).
6. Ensure that the...

PS1 (Input/Registration Sensor) Check
1Power ON the printer with the top cover open.  Wait for the
12 PRINTER OPEN (or CLOSE PRINTER COVER) message.
2Engage PS1 by taping it down.
aFor the LaserJet 5, install the toner cartridge.
3Close the top cover.  The 02 WARMING UP message should
display.
4After the fuser warms up, the main motor should turn on.
5The 13 PAPER JAM message appears if the sensor is working
correctly.  
6If the 13 PAPER JAM message does not appear, check that PS1
was fully engaged, then...

PS3 (Exit Sensor) Check
1Open the rear door (cover) of the printer.
2The display should read 13 PAPER JAM (or REMOVE PAPER JAM)
immediately after the door is opened.
3Close the rear cover.  The display should change from
02 WARMING UP to 00 READY.  
aIf the 00 READY message does not appear, check that the
rear door is not damaged, and the the door closes and
latches properly.
bIf the PAPER JAM message does not appear, replace PS3.
Pickup Motor Functional Test (M2)      
There is not a good method with...

Lower Cassette Functional Check    
When troubleshooting a Lower Cassette failure, always prove the
failure by removing the Lower Cassette from the printer. Next,
test the printer’s ability to move and print media satisfactorily
without the Lower Cassette installed.
The Lower Cassette is a field-serviceable item. The procedures for
removing and replacing the Lower Cassette components are in
Chapter 6. Replacement parts for the Lower Cassette Assembly
are listed in Chapter 8.  
After the failure has been...

14 NO EP CART Message    
The printer detects the presence of the Toner Cartridge and the
level of toner present in the cartridge through the condition of the
ANTIN signal. The ANTIN signal becomes part of the serial data
stream used to communicate with the DC Controller (see Figure
7-5 for cartridge components).  Troubleshoot the 14 NO EP CART
(or INSTALL TONER CARTRIDGE) message as follows:
1Reseat the Toner Cartridge.  Try a new or known good Toner
Cartridge.
2Check the High Voltage Contacts for...

1
245
6
3
Figure 7-5 Toner Cartridge Components
Callout Assembly
1 Toner Low Voltage Contact
2 Developer Roller High Voltage Contact 
3
Developer Roller
4
Photoconductive Drum
5 Charge Roller High Voltage Contact 
6 Charge Roller Table 7-8
Toner Cartridge Components 
7-26 Troubleshooting 

41.X ERROR Message  
A 41.X ERROR (misprint) indicates that a temporary malfunction
has occurred with the print engine (NOT a Formatter error).
Occasional occurrences of this message can be expected. However,
persistent 41 ERROR messages indicate a problem requiring
attention.
The 41.X ERROR is usually accompanied by a blank, or partially
printed page. Pressing the [Continue] (or Go) key re-prints the
page, and continues the print job.
A 41 ERROR occurs due to the following conditions:
•Incorrect...

Error Message Recommended Action
41.1 ERROR
Noisy Vertical Sync (VS)Reseat all connectors on the DC Controller, the Laser
Drive PCA, the Scanner Connector and the Beam Detect
Connector.
41.2 ERROR
Beam Detect (BD)
weak or unstable.Reseat all connectors on the DC Controller. Also check the
Laser Scanning Assembly connections.
41.3 ERROR
Paper Multifeed1. Incorrect size selection on the cassette.
2. One of the cassettes is overfull. Remove the extra
paper from the overfull cassette.
3. Check the paper for...

50 SERVICE Error - Fuser Malfunction  
WarningThe Fuser Assembly is HOT. Allow the assembly
time to cool before servicing.
The purpose of the fusing system is to maintain a constant
temperature on the fuser roller.  A high intensity fusing lamp,
located inside the fuser roller, provides the high temperature
required for the fusing process.  While the printer is in standby
mode, a temperature of approximately 172° C is maintained on
the fuser roller.  While the printer is in printing mode, a
temperature...

NoteThe 50 SERVICE error message can be cleared
immediately by shorting the C202 leads on the
HP LaserJet 4/4M (or the C205 leads on the HP
LaserJet 4 Plus/4M Plus/5/5M/5N) on the DC
Controller. Remove the Formatter PCA to access
the DC Controller as shown in Chapter 6.
Checks Action
Is the Fuser Assembly correctly
seated?Reseat the Fuser Assembly. Allow
adequate time for the error message to
clear (10 minutes) and turn the printer
ON.
Is the Fuser Bulb/ Thermoswitch open?
1.
2.The fuser bulb and...