HP 4 Plus Manual

							Jam LocationChecks 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 spring force of the Lower Cassette is set correctly.
Registration Area
Jams
(Sensed by PS1.) 1.  If paper is damaged at the Registration Sensor (PS1),
check that the Transfer Charge Roller is properly seated.
Lower Cassette
Paper Jams
(Sensed by PS1.) 1. The LC Tray (Tray 3) is not fully seated into the printer. Seat
the LC Tray firmly into the printer.
2. The Lower Cassette feed pressure (spring force) adjustment is incorrect. Set the spring force as shown in
Chapter 3.
Fuser Assembly
Jams
(Sensed by PS3.) 1. Check that the Fuser Pressure Roller Levers are down
(LJ4 and 4 Plus Only).
2. Check that the Exit Sensor Arm (PS3) is free throughout its travel and that the Exit Sensor Arm is installed correctly.
False Paper Jams
Paper Jam occurs
when the last
sheet of paper is
fed from the tray. 1. PS1, PS3, or PS5 are damaged or mechanically broken.
2. The sensor wires are damaged or disconnected.
3.
4.
The rear door is open.
Paper out sensors in the paper tray or envelope feeder
may be defective, or the sensor flags may be broken or
missing.  PS2 is the sensor for the PC Tray (Tray 2), PS4 is
the sensor for the MP Tray (Tray 1), PS6 is the sensor for
the LC Tray (Tray 3), and PS7 is the sensor for the
Envelope Feeder. 
Table 7-7Paper Jam Troubleshooting Checklist
Troubleshooting 7-21 
						

							PS1 (Input/Registration Sensor) Check
1Power ON the printer with the top cover open .  Wait for the
12 PR\fNTER OPEN  (or CLOSE PR\fNTER COVER ) message.
2Engage PS1 by taping it down.
aFor the LaserJet 5, install the toner cartridge.
3Close the top cover.  The  02 W\bRM\fNG UP message should
display.
4After the fuser warms up, the main motor should turn on.
5The  13 P\bPER J\bM  message appears if the sensor is working
correctly.  
6If the  13 P\bPER J\bM  message does not appear, check that PS1
was fully engaged, then replace PS1.
7Remove the tape from PS1, install the Toner Cartridge and
close the top cover.
8The display should change from  02 W\bRM\fNG UP to 00 RE\bDY .
If the  13 P\bPER J\bM  message persists, replace PS1.
Figure 7-4 PS1 Input/Registration Sensor
7-22 Troubleshooting 
						

							PS3 (Exit Sensor) Check
1Open the rear door (cover) of the printer.
2The display should read 13 P\bPER J\bM (or REMOVE P\bPER J\bM )
immediately after the door is opened.
3Close the rear cover.  The display should change from
02 W\bRM\fNG UP  to 00 RE\bDY .  
aIf the 00 RE\bDY  message does not appear, check that the
rear door is not damaged, and the the door closes and
latches properly.
bIf the  P\bPER J\bM  message does not appear, replace PS3.
Pickup Motor Functional Test (M2)      
There is not a good method with which to access the test points
around the Pickup Motor (M2) circuit.  Therefore, when
troubleshooting Pickup Motor failures, perform the following in
the order listed (see Figures 7-11 and 7-12 for component
location).
1Reseat J601 and J602 on the Paper Control PCA. 
2Reseat J201 on the DC Controller. Reseat J703 on the Sensor
PCA.
3Verify that the Paper Control PCA and the Sensor PCA are
firmly seated into one another.
4Replace the Pickup Motor.
5Replace the Paper Control PCA.
6Replace the Sensor PCA.
Troubleshooting 7-23 
						

							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 associated with the Lower Cassette
Assembly, perform the following in the order given.  Test the
repair after each replacement.
1Reseat all connectors in Lower Cassette.
2Replace the Lower Cassette Pickup Motor.
3Replace the Paper Control PCA.
4Replace the DC Controller.
7-24 Troubleshooting 
						

							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 C\bRT
(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 damage.  If the contacts
are dirty or damaged, clean the contacts after the repair.
3Replace the High Voltage Power Supply.  
4Check and reseat the HVPS cable.
5Replace the DC Controller.
16 Toner Low Message 
The TONER LOW  message results as the level of toner in the
cartridge cavity falls past the minimum level.  The level is sensed
by a mechanism similar to an antenna, which detects the AC
Developer Bias Voltage applied to the developer mixture.  If the 
TONER LOW  message cannot be cleared by shaking or replacing the
Toner Cartridge, perform the steps listed for troubleshooting the
14 NO EP C\bRT  message.
Troubleshooting 7-25 
						

							1
245
6
3
Figure 7-5 Toner Cartridge Components
CalloutAssembly
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 Universal Tray Switch setting. Set the Universal
Tray and the Lower Cassette Tray paper size as shown in
Chapter 3.
•Wrong size paper in tray. Check that the Universal Tray,
and/or the Lower Cassette settings match the installed paper.
•An unstable or temporary loss of the Beam Detect pulse.   This
problem normally is accompanied by a partially printed page,
often with thin horizontal black lines, deformed characters, or
solid black areas. Loss of the Beam Detect pulse for more than
2 seconds results in a  51 ERROR condition.
•Paper reaching the Input Paper Sensor (PS1) before it is
expected. This is accompanied by a blank page. This normally
is due to paper feed problems.  
Proceed as directed in the following table.
Troubleshooting 7-27 
						

							Error MessageRecommended 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 Multifeed 1. 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 edge damage. Improperly cut edges can lock together causing multi-feeds.
4.
5.  Check that the pickup rollers and separation pad are
not worn. Replace the rollers and pad as a set if
necessary. Ensure that the corners of the paper are
tucked in the tray
’s retainers.
Check the paper tension adjustment on the optional
Lower Cassette, if attached. Refer to procedure in
Chapter 3.
41.4 ERROR
Vertical Sync Late (VS)
Signal Reseat the DC Controller and Formatter PCA Connections.
41.5 ERROR
Undetermined Cause Reseat the DC Controller and Formatter PCA connections.
See Figures 7-11 through 7-17 for connector locations. Table 7-9
41.X ERROR Checks
7-28 Troubleshooting 
						

							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 of around 183 ° C is maintained.
The main components of the Fuser Assembly are the fusing lamp
and its associated fusing and pressure rollers, a thermistor,
thermoprotector, and the AC controller/safety circuitry in the AC
Power Supply.  The fusing lamp is a specially designed 460 watt
(220V), or 500 watt (115V) halogen lamp that operates at line
voltage.  The thermistor is a resistor whose value changes with
temperature.  At room temperature the resistance value of the
thermistor should be between 180k ohms and 280k ohms.The
thermoprotector is a switch designed for over-temperature
protection, and opens when the temperature reaches 230 ° C.  The
thermoprotector will not reset when the fuser cools.  It may be
necessary to replace the thermoprotector or fuser assembly if the
thermoprotector opens.
The following conditions result in a fusing error:
1Unable to maintain a temperature above approximately 
180 ° C.
2A temperature above 230 ° C.
3A condition wherein a temperature of 165 ° C is NOT reached
within 90 seconds after power-up.
Note  If a 
50 SERV\fCE  error message is displayed, turn
the printer OFF for at least 10 minutes. Failure
to wait the full 10 minutes before  turning the
printer ON results in a continuation of the error
message and the shutting off of the fuser lamp
current during this time, though the source of the
error may have already been resolved.
Troubleshooting 7-29 
						

							NoteThe 50 SERV\fCE
 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 thermoswitch are
wired in series. To check if one or the
other is defective, perform the following:
Remove the Fuser Assembly from the
printer.
Use an ohmmeter and measure the
continuity between pins (see Figure
7-6, callout 1). It should read about 2
ohms (about 4 ohms for the 220 volt
fuser). If an open condition is detected,
either the fusing bulb or the
thermoswitch is defective. Replace the
defective component (refer to Chapter
6) or replace the complete Fuser
Assembly.
Is the Thermistor defective? 1.
2. Remove the Fuser Assembly and let it
cool to room temperature.
Use an ohmmeter and measure the
resistance between pins (see Figure
7-6, callout 2) It should read about 220
K ohms +/- 40 K ohms at ambient
room temperature. If the thermistor is
either open or shorted, replace the
thermistor (refer to Chapter 6) or the
complete Fuser Assembly.
Does the error persist? 1.
2. Verify all cabling is correct.
Replace the following components in
the order given:
  Power Supply Assembly
  DC Controller PCA
See Figure 7-11  for Fuser Assembly location and Chapter 6 for
removal and replacement, as necessary. Table 7-10
50 SERVICE Fuser Malfunction Checks
7-30 Troubleshooting