HP LaserJet P4510 Service Manual - Page 255

Power-on defect or blank display, Table 7-2

Page 255 highlights

3. Make sure that the fan runs briefly, which indicates that the power supply is operational. 4. Make sure that the control-panel display wire-harness is connected to connector J70 of the DC controller PCA. 5. Make sure that the formatter is seated and operating correctly. 6. Remove any HP Jetdirect or other EIO cards, and then try to turn the product on again. NOTE: If the control-panel display is blank, but the main cooling fan runs briefly after the product power is turned on, try printing an engine test page to determine whether the problem is with the control-panel display, formatter, or other components. See Engine test on page 244. If the main cooling fan is not operating, replace the power-supply assembly. See High voltage power supply on page 206. NOTE: It is important to have the control panel functional as soon as possible in the troubleshooting process so that the control-panel display can be used to help locate errors. If problems with the power-on check persist, refer to table Table 7-2 Power-on defect or blank display on page 241. Table 7-2 Power-on defect or blank display Problem Action The power cord is not plugged into the wall receptacle and connected to the product. The correct voltage (power) is not available. The power switch is off. Make sure that the power cord is firmly plugged into the wall receptacle and connected to the product. Measure the voltage at the outlet. If necessary, plug the power cord into another circuit outlet. Set the switch to the on position. You should hear the switch toggle. If the front rightside cover has been removed recently, make sure that the rod connecting the powersupply switch moves as you toggle the switch. See the reinstall note in Reinstall the right cover on page 162. If the product still does not turn on, the power switch might be defective. 1. Remove the power supply. 2. Measure the resistance between the two terminals of the power switch (SW1) by applying the tester probes to the terminals. The resistance must be low (under 1 K/ohm) when the power is turned on, and high (over 6 K/ohm) when the switch is turned off. The overcurrent/overvoltage detection circuit is activated. 3. Replace the power-supply assembly, if necessary. Wait for more than two minutes before turning the product back on. A fuse is blown. 1. Check the fuses (FU1 and FU2) on the power supply. 2. Replace the power-supply assembly if necessary. The main cooling fan (located on the left An operational fan indicates the following conditions: side near the rear of the product) does not turn on when the product is started. ● The AC power is present in the product. ● The DC power supply is functional (24 V, 5 V, and 3.3 V are being generated). ● The DC controller microprocessor is functional. ENWW Troubleshooting process 241

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3.
Make sure that the fan runs briefly, which indicates that the power supply is operational.
4.
Make sure that the control-panel display wire-harness is connected to connector J70 of the DC
controller PCA.
5.
Make sure that the formatter is seated and operating correctly.
6.
Remove any HP Jetdirect or other EIO cards, and then try to turn the product on again.
NOTE:
If the control-panel display is blank, but the main cooling fan runs briefly after the product power
is turned on, try printing an engine test page to determine whether the problem is with the control-panel
display, formatter, or other components. See
Engine test
on page
244
.
If the main cooling fan is not operating, replace the power-supply assembly. See
High voltage power
supply
on page
206
.
NOTE:
It is important to have the control panel functional as soon as possible in the troubleshooting
process so that the control-panel display can be used to help locate errors.
If problems with the power-on check persist, refer to table
Table
7
-
2
Power-on defect or blank display
on page
241
.
Table 7-2
Power-on defect or blank display
Problem
Action
The power cord is not plugged into the
wall receptacle and connected to the
product.
Make sure that the power cord is firmly plugged into the wall receptacle and
connected to the product.
The correct voltage (power) is not
available.
Measure the voltage at the outlet. If necessary, plug the power cord into another
circuit outlet.
The power switch is off.
Set the switch to the
on
position. You should hear the switch toggle. If the front right-
side cover has been removed recently, make sure that the rod connecting the power-
supply switch moves as you toggle the switch. See the reinstall note in
Reinstall the
right cover
on page
162
.
If the product still does not turn on, the power switch might be defective.
1.
Remove the power supply.
2.
Measure the resistance between the two terminals of the power switch (SW1)
by applying the tester probes to the terminals. The resistance must be low
(under 1 K/ohm) when the power is turned on, and high (over 6 K/ohm) when
the switch is turned off.
3.
Replace the power-supply assembly, if necessary.
The overcurrent/overvoltage detection
circuit is activated.
Wait for more than two minutes before turning the product back on.
A fuse is blown.
1.
Check the fuses (FU1 and FU2) on the power supply.
2.
Replace the power-supply assembly if necessary.
The main cooling fan (located on the left
side near the rear of the product) does
not turn on when the product is started.
An operational fan indicates the following conditions:
The AC power is present in the product.
The DC power supply is functional (24 V, 5 V, and 3.3 V are being generated).
The DC controller microprocessor is functional.
ENWW
Troubleshooting process
241