HP 3150 EN - Manual (Page 181)

EN Functional checks 179
Heating element check
1 Paper passes between the heating element and a soft pressure
roller to fuse toner to the paper. To verify that the heating element
is functioning correctly:
2 Unplug the HP LaserJet 3100/3150 product for at least ten
minutes.
3 Verify that the thermistor connector (see Figure 46) is seated into
both the printer chassis and J206 of the ECU.
4 Remove the heating element connector (see Figure 45) from the
ECU. To measure the continuity of the heating element, measure
the resistance between pins one and two of the cable.
Note Normal resistance is 30 ohms +/- 10 ohms.
5 If no resistance is measured, replace the heating element.
6 Remove the thermistor connector (see Figure 46) and measure
the resistance between pins one and two.
Note Normal resistance is 440K ohms +/- 30K ohms at 68° F (20° C).
7 If no resistance is measured, replace the heating element.