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Power Supply Trouble Shooting Notes:
2010/2011 models
Will not be run with the “X” or “Y” main disconnected. The SMPS will
shut down immediately. However if a meter is first connected to the
test point when power is applied it will read the correct voltage briefly
before shut- ting down.(You have enough time to check key
voltages)
CAUTION: Do not reconnect any connectors to SMPS or Y/X Boards
until power has been turned off long enough for Vs to drop below 10V
or damage will occur to X or Y Boards.
SMPS Over Current Protection
If a short circuit occurs on either the VS or VA voltage lines, the SMPS
stops operating, but should not fail. When the short circuit is removed
from the source line, the Power Supply will operate normally again.
Many SMPS Supplies are replaced needlessly!
If Vsc is low or missing and Vs is OK, the failure is with the Y-Board
since the Y-Board generates the Vsc voltage from the supplied Vs.
If Ve is low or missing and Vs is OK, the failure is with the X-Board since the
Ve is generated by the X-Board from the supplied Vs. (Please note: In some
rare cases the Ve is generated by the Y-Board fed to the X-Board.)
Other SMPS Voltages:
Check Low Voltage feeds to the Main Board and other supplied Assemblies.
Sample
“VITAL SIGNS”
When troubleshooting, It’s very important to first check Vs, Va, Vsc & Ve
If Vs is missing (0V), disconnect power and check for short. Use ohm
meter to measure resistance while disconnecting Y-Board & X-Board
supply feeds one at a time.
Turn Power On and Test SMPS with shorted connector removed for
correct Vs voltage verification. (It may only come up briefly but to full
level). Be careful not to reconnect power connectors until Vs falls below
10V.
If Va is low or missing, disconnect power connectors to Address Boards
and Check to see if SMPS Supply is restored. (Note Va feed normally
passes through the Y-Drive to the Address Boards (Logic Buffer Boards).
.
Fast Track Troubleshooting Manual
PN58C6400TFXZA