HP LaserJet 5Si user guide
Page 160
... call your card supplier, or authorized HP dealer or service representative. If the error appears again, record the numbers following the error message and call your HP-authorized service provider. Switch the printer OFF and then back ON. 79 SERVICE (xxxx) CALL SERVICE An internal controller error occurred. xxxx indicates the error type. EN Maintenance and Troubleshooting...
... call your card supplier, or authorized HP dealer or service representative. If the error appears again, record the numbers following the error message and call your HP-authorized service provider. Switch the printer OFF and then back ON. 79 SERVICE (xxxx) CALL SERVICE An internal controller error occurred. xxxx indicates the error type. EN Maintenance and Troubleshooting...