HP Laserjet 5 problem

[leesgritt]

We have a HP Laserjet 5 in one of our offices that keeps giving the 79 service error. We can reset this so it will continue to work but the display on the printer just scrolls HP LASERJET 5 DEMONSTRATION MODE even though it prints fine. Does anyone know how I can get rid of this anoying message. I have a service manual that tells me what the 79 service error is but there are more digits at the end of the error that give the exact fault (I don't have the digits to hand, someone reset the printer before I got there) so does anyone know how I can find out what the extra code means without having to pay a small fortune to HP? Thanks for any help you people can give.

Regards,
Lee.

 

[Melapa]

Basically 79 errors are commands sent to a printer that is not understood on the printer ( most 49 errors on later models are the same thing ).

This can be caused by the firmware in the unit. To be honest it is not nessecary to know what the numbers are, but basically what is causing them: Basically the firmware has detected a failure within the formatter. This failure can be caused by defective MIO devices, communication ports, or cables.

Usually what we find is that this issue is caused by software, and that a cold reset on the printer will clear the error before jobs are sent to the printer.

If the error comes up immediately after a cold reset before re-connecting to a PC then the issue is mostly likely caused by the formatter in the printer

 

[hpwizzard]

A cold reset might get rid of this message.

1) Turn OFF the printer.
2) Hold the GO key down while powering ON the printer. The message COLD RESET is displayed. The COLD RESET does not take effect until the 00 READY message is displayed.
3) When the 00 READY message is displayed, the default settings have been returned to the factory defaults, and the printer is ready to accept new settings.

Beware that any cold reset will delete previous non factory settings on the printer including networksettings like an IP address.