Philips QFU2 1E Chassis LCD TV SMPS circuits troubleshooting

Power Supply Unit
For 32", 37", and 55" sets, power supply units should be repaired on component level. All other power supplies are a black box for Service. When any of these power supplies is defective, a new board must be ordered and the defective one must be returned, unless the main fuse of the board is broken. Always replace a defective fuse with one with the correct specifications. This part is available in the regular market.
Replace safety components, indicated by the symbol , only by components identical to the original ones. Any other component substitution (other than original type) may increase risk of fire or electrical shock hazard.

PLDC-P109B (32" sets) and PLDD-P109A (37" sets)

The output voltages to the chassis are:
* V STB (+3.3 V; stand-by mode)
* V SSB (+12.3 V; on-mode)
* V SND (+12.3 V; audio circuit).

Test instructions 32" & 37"

* check fuse (F101)

* standby check VSTB (C306), measure 3.3 V

* PFC voltage check (C644), measure 380 - 400 V; if no PFC applied, measure 311 @ 220 V

* multi-level check V SSB (C203), measure 12.3 V

* multi-level check V SND (C206), measure 12.3V

* reference voltage check (U401), measure 5.96 V (appr.).

PLDK-P107B (55" sets)

The output voltages to the chassis are:

* V STB (+3.3 V; stand-by mode)

* V SSB (+12.3 V; on-mode)

* V SND (+12.3 V; audio circuit).

Test instructions 55"

* check fuse (F101)

* standby check VSTB (C301), measure 3.3 V

* PFC voltage check (C646), measure 380 - 400 V; if no PFC applied, measure 311 @ 220 V

* multi-level check V SSB (C203), measure 12.3 V

* multi-level check V SND (C202), measure 12.3V

* reference voltage check (U401), measure 5.96 V (appr.).

A 272217190604 - 272217190605 PSL. Power Supply Unit with Integrated LED Driver Schematic

A 272217190609 PSU Circuit diagram

A 272217190611 PSU Circuit diagram

Comments

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