3-16
Workstation 5 Field Service Guide
Workstation 5 Troubleshooting
Checking the Power Supply and System Board Voltages
1. Start with the +12V output from the power supply at J16.
o
If +12V is not available, remove the AC Power Cable and check the
power supply fuse located near the AC input connector.
o
If the fuse is OK, but the power supply produces no output, check the
AC input cabling through the AC input connector mounted to the
chassis.
o
If +12V is not available, replace the Power Supply.
2. If +12V is available, check
VCC5SB
at the (IN)put pin of adjustable
regulator U42.
VCC5SB
is generated by regulator #1 in U38. This regulator
is configured to run as long as +12V is available.
3. If
VCC5SB
is available, check
VCC3SB
at the (OUT)put pin of adjustable
regulator U42.
4. If
VCC5SB
is available, check
VCORESB
at the junction of D21 and TC36.
VCORESB
powers the LX800 Processor and TFT Controller.
5. If
VCC3SB
is available, check
VCC1.8SB
at U28-Out.
If the Standby voltages are present, but the board will not start when you press
the power button, see the next page.