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Philips LCD no DC voltage in output
Hi guys,
ANSWERS:
"@gianlucarbone this is long to post as a comment but definitely a good read to check a few more things. “Power Module Repair
In the absence of any signs of operability, when the PHILIPS 37PF5604H / 60 does not turn on and does not signal anything with the control lights on the panel, the PLHL-T845A power supply module is most likely faulty. When diagnosing and repairing the power supply, after replacing the swollen capacitors of the secondary rectifier filters (if any), you must first check the mains fuse. If it is broken, check the power switch FQPF3N80. K3561 and rectifier bridge diodes for avalanche (thermal) breakdown.
It should be borne in mind that in the repair practice it is extremely rare that key transistors of the N-FET type fail for no reason that should be looked for by checking other components, for example, a breakdown of the key can provoke faulty elements of the damper circuits, either dried electrolytic capacitors or dangling resistors of the primary circuit of the PSU, involved in the stabilization process. In this case, all the semiconductor elements of the strapping of the PWM regulator chip FSQ510 (7), dezh 1207A, prk FAN7530, which should be checked by replacement, are subject to verification. of any signs of operability, when the PHILIPS 37PF5604H / 60 does not turn on and does not signal anything with the control lights on the panel, the PLHL-T845A power supply module is most likely faulty. When diagnosing and repairing the power supply, after replacing the swollen capacitors of the secondary rectifier filters (if any), you must first check the mains fuse. If it is broken, check the power switch FQPF3N80. K3561 and rectifier bridge diodes for avalanche (thermal) breakdown.
It should be borne in mind that in the repair practice it is extremely rare that key transistors of the N-FET type fail for no reason that should be looked for by checking other components, for example, a breakdown of the key can provoke faulty elements of the damper circuits, either dried electrolytic capacitors or dangling resistors of the primary circuit of the PSU, involved in the stabilization process. In this case, all the semiconductor elements of the strapping of the PWM regulator chip FSQ510 (7), dezh 1207A, prk FAN7530, which should be checked by replacement, are subject to verification.
PLHL-T845A power supply unit using the PFC (Power Factor Correction) node - an active filter of the highest harmonics of the current consumption. In fact, this is a boost converter based on the FAN7530 PWM controller, which eliminates the charge current of the electrolytic capacitor of the rectifier filter directly from the network through open diodes, when its charging current is determined by its reactance.
As a result of the operation of the converter, the envelope of the high-frequency pulses of the input current of the converter will repeat the shape and phase of the input voltage. The health of the PFC node can be indirectly judged by the presence of an increased constant voltage (about + 380V) on the capacitor of the rectifier network in operating mode.
The appearance of the power supply
Main features of the PHILIPS 37PF5604H device:
Installed matrix (LCD panel) LC370WUE (SB) (A1) code 201.
To power the backlight, the PLHL-T845A inverter is used, controlled by the OZ9966GN PWM controller (24). As power elements of the inverter, keys of the FDD5N50 type are used.
The necessary supply voltages for all nodes of the PHILIPS 37PF5604H TV are generated by the PLHL-T845A power module or its analogs using FSQ510 (7), 1207A, FAN7530 (PFC) microchips and power switches of the FQPF3N80 type. K3561. from here
Update (05/25/2020)
@gianlucarbone this seems to really go down a rabbit hole. I sourced the service manual which appears to also have the schematics you need to double check. From following this thread my first suspect is the main board followed by the power board. See if the manual will help you out Q543.3E LA, 3122 785 18443, 100629"
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