Test Points And Led's - HP Designjet 3D Service Manual

Test Points and LED's

Test points and LED's are very useful for troubleshooting the system. The test
points and LED's are listed below with a brief description.
Figure 6: Test points and LEDs detail
Test Pt. Description
Component
UPS TP29
+5V REF TP24
Door Switch TP15
On/Off Switch TP14
Power Enable TP8
Model Toggle TP17
Chamber TP28
Thermocouple
Support TP20
Thermocouple
Model TP22
Thermocouple
HD Thermostat TP25
Head TC Alarm TP26
Support Toggle TP16
Chamber TC TP27
Alarm
Power fail signal from external UPS
Head T/C service reference
State of the door (open or closed)
State of power down switch
Enables power to circuitry (normally high)
Toggle travel complete
Voltage corresponds to chamber temperature
(10 mV=° C)
Voltage corresponds to support temperature
(10 mV=° C)
Voltage corresponds to model temperature
(10 mV=° C)
Chamber and head thermostat (snap
switches)
(+5 VDC if both switches closed)
Normal = tp17 lo, tp19 hi
ch thermostat fault=tp17 lo, tp19 lo.
High if head T/C not plugged in or open
Not used
High if chamber T/C not plugged in or open
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