HP LaserJet Pro MFP M329dw

Power-on troubleshooting overview

During normal operation, a cooling fan begins to spin briefly after the printer power is turned on. Place a hand over the fan intake vents located on the right-side cover. When the fan is correctly operating, air passing into the printer is felt. Lean close to the printer to hear the fan operating. If the fan is operating, the dc side of the power supply is functioning.

After the fan is operating, the main motor turns on (unless the top cover is open, a jam condition is sensed, or the paper-path sensors are damaged). Visually and audibly determine that the main motor is turned on.

If the fan and main motor are operating correctly, the next troubleshooting step is to isolate print engine, formatter, and control panel problems. Perform an engine test. If the formatter is damaged, it might interfere with the engine test. If the engine-test page does not print, try removing the formatter, and then performing the engine test again. If the engine test is then successful, the problem is almost certainly with the formatter, the control panel, or the cable that connects them.

Perform an engine test

With the printer on and in the Ready state.

Simplex models

1. Open and close front door.
2. Open and close front door again within 1.5 seconds.
3. Repeat step 1 and step 2 four times and one sheet of the test pattern prints on the front of the page.

Duplex models

1. 1. Open and close front door.
2. Open and close front door again within 1.5 seconds
3. Repeat step 1 and step 2 five times and one sheet of the test pattern prints on both front and back of the page.

Troubleshooting power on problems

1. Verify that power is available to the printer. If the printer is plugged into a surge protector or uninterruptible power supply (UPS), remove it, and then plug the printer directly into a known operating wall receptacle (make sure that the wall receptacle provides the correct voltage and current for the printer). Unplug any other devices on the same circuit that the printer is using.
2. Try another known operating wall receptacle and a different power cord.
3. Listen for startup noises (fans and motors) and illuminated lights on the control panel.
   NOTE: Operational fans, motors, and control-panel lights indicate the following:
   • AC power is present at the printer.
   • The low-voltage power supply (LVPS) is providing either or both 24 Vdc and 5 Vdc voltages.
   • The DC controller microprocessor is functioning.
4. If startup noises are not heard, check the following:
   a. Turn the printer off, and then remove the power from the formatter.
   b. Turn the printer on, and then listen for startup noises. If normal startup noises are heard, go to step 5.
   NOTE: The control panel will be blank with the formatter removed.
   c. If normal startup noises and lights are still not present, replace the LVPS.
   d. If after replacing the LVPS normal startup noises are still not heard, replace the DC controller.
   NOTE: If the error persists after replacing these assemblies, escalate the problem to the Global Business Unit (GBU).
5. Try printing an engine test page.
   NOTE: The test page can only use Tray 2 as the paper source, so make sure that paper is loaded in Tray 2.
   ▪ With the printer on and in the Ready state, open and then close the front door four times (for a simplex print out on both simplex and duplex models) or five times (for a duplex print on duplex models). The printer prints the engine test page.
   If the engine test page prints, the print engine is operating normally (a failed engine test print page does not necessarily indicate that the print engine or DC controller is defective).
   NOTE: If the engine test page does not print, turn the printer off, remove the power from the formatter, and then try the engine test again. If the page prints, the problem might be the formatter.