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.