User's Manual
HP Designjet T Series — Service Manual 2-35
Appendix A: How to troubleshoot SE 79:04
Solutions and workarounds
When a job consistently generates a 79:04 system error, it is either because 
of a issue in the printer’s firmware or because of a defect in the job itself 
(when it has been generated by 3rd party SW). In order to identify the 
cause and find out a solution, these issues should always be immediately 
escalated to the GBU through the GCC.
Also, there are a set of workarounds and short term solutions that can be 
te
sted in order to get the customer up and running in the shortest possible 
time:
1 Send the 
j
ob using a variety of different settings. Many times, the issue is 
caused by a combination of the job contents combined with some specific 
setting(s).
2 If 
the customer is sending the file directly to the printer, try using the HP 
dr
iver instead.
3 If the issue is occurring when printing t
hrough the HP PostScript driver from 
an application with PS passthrough, try changing the options in the 
application so that it prints PS as raster (the option is typically located in the 
“Advanced” options of the application’s printing dialog).
Data related SE79:04
HP Designjet printers have Hard Disks and non volatile memories that 
conta
in data bases and files that can be modified with user data. Some 
examples include:
 The printer’s queue
 The hard drive partitions that contain user jobs
 The data base that stores the printer settings
 The data base that stores accounting information
Some of this data is accessed by the printe
r at start up, and some others are 
accessed as needed.
If any of this fields contains corrupt data or data with characters or values 
that cannot be corr
ectly processed by the printer, a 79:04 system error may 
occur.
Possible symptoms
There are two different types of symptoms for data related 79:04 system 
err
ors:
1 When the corrupt data is accessed during start up:
a The printer will display a 79:04 during the start up process
b Switching the printer off and on again w
ill not solve the issue. The printer 
will continue displaying the 79:04 system error until the corrupt data has 
been cleared through a service procedure
2 W
hen the corrupt data is accessed during normal printer operation
a The printer will start up normally
b When the data is accessed (for example while printing, while navigating 
the 
queue or when changing some settings), the printer displays a 79:04 
system error










