PN50C450B1DXZA - HOW
TO ACTIVATE POWER and LOGIC BOARD TEST PATTERNS WITHOUT MAIN BOARD
HOW TO ACTIVATE POWER and LOGIC
BOARD TEST PATTERNS WITHOUT MAIN BOARD
> Remove the power cord to panel.
> Short highest 2 pins # on logic
board test jig (can be 4 pin or 6 pin)
> Remove power connector at main
board; Keeping connection to SMPS.
> Short “Power On” Pin to circuit
ground on Power connector to SMPS.
> Connect Power cord to Panel.
Power Supply
Trouble Shooting Notes
Do not
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 shutting down. (You
have enough time to check key voltages)
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.
Over Current
Protection
For the SMPS Power Supply
For the SMPS Power Supply
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.
SAMPLE VIEW – READINGS &
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 short
connector removed for correct Vs voltage verification. (It may only come up
briefly but to full level). Again be careful not to reconnect Power Connectors
until Vs falls below 10V.
If Va is low or missing, disconnect Supply Feed 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).
If Vsc is low or missing and Vs was OK, the failure is with the Y-Board since the Y-Board generate the
Vsc voltage from the Vs supplied by the SMPS.
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 Vs supplied by the SMPS. Note: in some rare cases the Ve may be generated by
the Y-Board feed to the XBoard.)
Other SMPS
Voltages
Check Low Voltage feeds to the Main Board and other supplied Assemblies.
Check Low Voltage feeds to the Main Board and other supplied Assemblies.
Click on the Pictures to Zoom In.
