+24B Vdc Functional Check - HP LaserJet II Serie Manual De Instrucciones

HP 33440/HP 33449 COMBINED SERVICE MANUAL
+24B Vdc Functional Check
For an explanation of the source of the +24B Vdc power, read the overview for the "12 PRINTER
OPEN" message on the previous page.
To verify if the + 24B Vdc power supply is functional, proceed as follows:
1. Remove the access cover(s) to the test connector (J21O, next to the Test Print Button).
2. Using a voltmeter with frame ground as a reference, monitor the voltage at J21O-11 while
manually activating the printer Top Cover Assembly closed microswitch (see Figure 7-6 and
Figure 7-7). The measured voltage should toggle from zero to +3.2 Vdc (*5%) as the switch is
activated. If the voltage is present yet the message persists, replace the DC Controller PCA.
If the voltige is not present, + 24B Vdc (*5%) can be measured at J212-13 (bottom cover must
be removed) while activating the Top Cover Assembly closed microswitch (see Figure 7-6).
If + 24B is not presen~ replace the DC Power Supply Assembly. If + 24B is present but + 3.2 V
is not the DC Controller PCA is defective.
~ Insefi N on-MetalliC
Object into Opening
to tilvate Microswitch
Figure 7-6.
Defeating the Top Cover Assembly Microswitch
w
'2'0
I
I
I +3.2V
+24~
-5V
+5V
Figure 7-7. J210 Test
connector
Test Point
7-28