Friday, July 8, 2016

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