Philips 47PFL7403D/10

[Davi.p]

Re: Philips 47PFL7403D/10

You never talked about D107, on the auxiliary out of T101, if it is good then i would carefully disassemble T101 to find a short, you're probably been able to reassemble it in case of no shorts.

[vazaki]

Re: Philips 47PFL7403D/10

Thank you Dav

D107 is good.

I can't find T101. Can you help me please?

[tvtimmy]

Re: Philips 47PFL7403D/10

T101 is the transformer you pulled.

[vazaki]

Re: Philips 47PFL7403D/10

I ahve already desolded the T101 tranformer.

The secondary tested with blue ring tester and seems bad. With multimeter the value is 0ohms

I believe this is the problem

Do you know where can I find such part?

[Davi.p]

Re: Philips 47PFL7403D/10

I don't tell to desolder... i say disassemble it... remove the kapton tape, unroll the wire until you find the short... but if you thrust you meter then i don't know where to find replacement, never bought one.. if you have time to spend, you can buy an enameled wire and reconstruct it..

[vazaki]

Re: Philips 47PFL7403D/10

Thanks David!

I haven't done such thing before. Is it easy?

[Davi.p]

Re: Philips 47PFL7403D/10

i dont know, never done..., obviously you have to count orginal rounds...

[abba81]

Re: Philips 47PFL7403D/10

Did you resolve the problem?

[Davi.p]

Re: Philips 47PFL7403D/10

original turns... ehm, not "rounds"..

[lookimback]

Re: Philips 47PFL7403D/10

I'm working on a 42" but that portion of the circuit (RCD snubber) looks identical. I have 2 boards with the exact same failed IC. I have a third which works. All three test 0.1 ohms on the secondary of T101. The 2 bad ones had U101 (FSQ510)with it's drain pin blown off. I can't find any shorted components around it. D106A is open, as it should be, but I'm wondering if it's break down threshold has changed.

[kripton2035]

Re: Philips 47PFL7403D/10

Hi here,
same power supply board here, clicking and no power.
Philips 47PFL7403D/10
power supplyQ PLHC-T801A (UD)
already replaced R5 that was burned, and U101 that was exploded.
no more burning of these two, but still relay clicking.
can anyone publish here the schematic of this power supply ?

I found that ZD101 seems shorted (or PC101 ?) will investigate that option.
thanks.

[kripton2035]

Re: Philips 47PFL7403D/10

in fact, it's not zd101, it's the replaced U101 that has pin 3 (feedback) shorted to ground...
I must replace it again, but what else can it be ?
TR101 has inductances on all windings
all diodes verified good, zener seems ok too (no short)

[budm]

Re: Philips 47PFL7403D/10

The feedback is connected to very low Ohm resistor to GND to sense the current through the power MOSFET.

[kripton2035]

Re: Philips 47PFL7403D/10

thanks.
again, can anyone share the schematic of this power supply PLHC-T801A ?
I found dozens of phillips service manuals, with many schematics, but never the power supply !
I'm pretty sure I found the service manual of the real TV I try to repair thanks to the pictures,
(phillips is pretty good at loosing the technician in an ocean of manuals...).
I found some schematics of phillips 47" power supplies, but never one corresponding to the one I need.
TIA.

[JoseRafael]

Re: Philips 47PFL7403D/10

Dear Budm, do you have the correct schematic for this board??

Is this the same board?
http://www.shopjimmy.com/philips-272...pply-unit.htm#
Philips 272217100571 (2300KEG033A-F) Power Supply Unit.
MFR Part Number 1: Philips 272217100571
Board Number(s): 2300KEG033A-F, PLHL-T722A 2722, 171 00571
Substitute Parts: 272217152611, 272217100571 Repair Kit

R5 is used to supply B+ (rectifiers D101A~D) to run the standby SMSP IC U101, once the TV is power sup, the B+ will be then supplied by the main power supply through D160, 160A., once the main power supply relays are on then R5 is no longer in use, if B+ through D160,160A is not present and the main board will try to pull full current from STBY supply, then R5 will burn up, that R5 is used just enough to supply enough current to run the main board through R5, once full power is required, R5 is no longer used in the circuit due to reverse bias of D101A~D.
So something is drawing too much current through R5 and causes it to burn up, U101 is one of the load.
The RCD snubber for the U101 is OK? The rectifiers D111 in the cold side is OK? D101A~D, D160, 160A OK?

[zape]

Re: Philips 47PFL7403D/10

The feedback is connected to very low Ohm resistor to GND to sense the current through the power MOSFET.

but not throug the pin3. This is what I found here on the forums about FSQ510: "The voltage on Pin 3 (Vfb) should be close to 2.8V when the PSU is operating normally and 4.7V when in overload protection."
The relay tries to turn on but it is not provided enough voltage to turn on.
pin3 of U101 seem to be shorted to ground, and that's the reason why IC is not working correctly and does not provide enough voltage to switch on the relay

[zape]

Re: Philips 47PFL7403D/10

in fact, it's not zd101, it's the replaced U101 that has pin 3 (feedback) shorted to ground...
I must replace it again, but what else can it be ?

Did you figure it out?
I observe the same symptoms

[R_J]

Re: Philips 47PFL7403D/10

On a FSQ510, pin 2 is ground, pin 3 is VFB and has a small cap. to ground, it also connects to the optocoupler which may also have a zener diode across it, the zener or opto may be shorted

[zape]

Re: Philips 47PFL7403D/10

On a FSQ510, pin 2 is ground, pin 3 is VFB and has a small cap. to ground, it also connects to the optocoupler which may also have a zener diode across it, the zener or opto may be shorted

I checked it with pin3 desoldered.
Two ICs already died like that.

[kripton2035]

Re: Philips 47PFL7403D/10

Did you figure it out?
I observe the same symptoms

sorry, we found a replacement power supply, and leaved it like that (without schematic ... ) I still have this board with the same symptoms: relay clicking.
would still like to fix it ...