[Philips TV] 47PFL5604H backlight/inverter

[otoluk]

I have got defective 47PFL5604H which has no backlight but it turns on and has audio output to speakers, LCD works. Connecting SDM service pin it flashes Fault code 17

Power Board: DETA DPS-298CP-2A (Philips S272217100701/S272217100702)

Error 17 (Invertor or Display Supply). 
Here the status of the “Power OK” is checked by software, 
no protection will occur during failure of the invertor or display supply (no picture), only error logging. 
LED blinking of LAYER 1 error = 3 in CSM, in SDM this gives LAYER 2 error = 17.

History: The TV previously had issues that in hot summer it sometimes didn't turn on. Finally it had blown mains fuse when turning on while TV fuse remain intact. Upon inspection large cap(Rubycon 450V 150uF ) C808 under heatshield seems to be leaking at side and visible black soot but no other damage. Other capacitors are quality Rubycon or Nichicon series. Interesting that NTC4(thermistor) is attached to PCB and not to heatsink.

Replacing large cap didn't help and still no backlight what else to check? Maybe NTC kicks some protection?

As rebuild kit for this board there is these parts included but would not like to change all blindly if it is not bad.

Repair kits include:
D907,D911
C961,C705,C709,C731,C734
C316?,C371?
D908?,IC901,Q801?

[Andrew F. Ali]

Re: [Philips TV] 47PFL5604H backlight/inverter

The parts the repair kit suggests to replace, if you don't want to change them blindly then test them and determine if you want to not change them. If you don't know how to test components and you do have them then by all means go ahead and change them out. You would need a DMM to test the diodes and transistor, an ESR meter to test the capacitors and the Data sheet to test the voltages on each pin of IC 901. However, testing the backlights to see if they are working would require some voltage readings from the supply feeding the backlights. I doubt it that you have software problem and when the information you have say 'display' they are referring to the backlights as well.

[dskall]

Re: [Philips TV] 47PFL5604H backlight/inverter

Do you hear any arcing or smell any ozone. You will probably need to open it up and inspect backlights.

[otoluk]

Re: [Philips TV] 47PFL5604H backlight/inverter

Forgot to mention that the TV was previously sent to Philips service for diagnostics and it was sent back as not repairable as power board is no more available but they tested backlights with different power board and they are ok.

Ok will check listed components first.
I noticed that some of the DPS-298CP-xx boards don't have thermistor so maybe it can be soldered out?! I read that NTC has high in-rush current which may trigger some protection and I do not see reasoning why it is placed on PCB.

[otoluk]

Re: [Philips TV] 47PFL5604H backlight/inverter

DPS-298CP-2 schematics

http://tel-spb.ru/files/Power_Philips_DPS-298CP-2.rar

Replaced C731/C709/C734/C705/C808 and it didn't help much. T901 inverter is clicking but no backlight.

The PFC will not be turned on unless power is turned on. That's normal. The power supply is built around IC901, an ICE3BS03. It gets its startup voltage on pin 5 via zener ZD907 (36V). Once power is started, the IC receives its power supply on pin 7 via Q916 and D906 from the transformer.
Adequate points of interest to agree.

[dskall]

Re: [Philips TV] 47PFL5604H backlight/inverter

Need good clear straight on pictures of back of tv with cover off and each board.

[R_J]

Re: [Philips TV] 47PFL5604H backlight/inverter

Do you have B+ on Q301a ? Also whats the voltage at pin 16 (vcc) of ic601

[otoluk]

Re: [Philips TV] 47PFL5604H backlight/inverter

Voltage on Q301a is ~16V AC and at pin 16 it is ~15.8V AC

Tested T901 transformer pins connections while off and they are ok.

Attaching picture of back of the board(little bit messy as resoldered some parts for testing)

[budm]

Re: [Philips TV] 47PFL5604H backlight/inverter

Ac???

[otoluk]

Re: [Philips TV] 47PFL5604H backlight/inverter

Didn't get any measurements in DC, it was zero for both pins. Q301pin is connected to transformer shouldn't it be AC?

I measured against screws at corners maybe that is not a good reference point.

[otoluk]

Re: [Philips TV] 47PFL5604H backlight/inverter

Ok, tested Q301A and Q301B they are shot. Also R344(1 ohm?) is open.

Will replace and check then.

Resistor is 5 band but can't verify it's value. Is it 1 or 0.1ohm?

[otoluk]

Re: [Philips TV] 47PFL5604H backlight/inverter

Replaced Q301A and Q301B (P10NK60ZFP) with P12NM50FP as didn't find exactly the same part. Also replaced R344 with 0.2ohm resistor.

Now when turning on it tries to strike few times and there is voltage spike of 40V on VCC and I hit overvoltage(>600v) beep on my multimeter on Q301A. Same overvoltage spikes I get on T301 input. Still backlight doesn't turn on. C731/C709/C734/C705/C808 are already replaced.

The burnt-out resistor indicates a short circuit of Q301a(type P6NK60ZFP), and resistor maybe goes defective when one of the capacitors C306A/C306B is no longer in order?

Error 17 (POK). The display is switched “on” with the
signal “Lamp On”. If the inverter starts (or 24V display is
OK) the POK line becomes “high”. If the POK line is not
“high”, the set backlight will be switched “off” and “on” again
for 3 times (start-up). If the set POK line becomes “high”
after the retries, no error is logged; if the POK stays “low”,
error is logged: LAYER 1 error = “3”, LAYER 2 error = “17”.
No protection is required, the start-up goes on.

[R_J]

Re: [Philips TV] 47PFL5604H backlight/inverter

R344 acts like a fuse between the B+ and B+++ It went open because Q301A & B shorted, IF they shorted from drain to the Gate, D303/312 or R333/338 could be bad OR the IC601 could have been damaged.
The vcc on pin 16 of ic601 should not exceed +20 volts if it is a DDA002C. It looks like it gets the VCC-on from IC4 (which I dont know what it is) if it's a regulator of some sort it could be bad?

[otoluk]

Re: [Philips TV] 47PFL5604H backlight/inverter

IC4 is DDA005
Its counterpart is DDA005 = M29150 Link

[torentino]

Sorry for late thema resurrection. Anybody has values of element around IC901 3BS3LJ. Had a full explosion of nearby elements, specially R926, r927, C918, D908 and q901.

[torentino]

Sorry for late thema resurrection. Anybody has values of element around IC901 3BS3LJ. Had a full explosion of nearby elements, specially R926, r927, C918, D908 and q901.

OK, find it by myself:
R926-22R
R927-1K
c918-220pF 50V
R903-0,18R
R901-0,1R
Q901-2SK4101
R926-22R
R923-100R

[otoluk]

Re: [Philips TV] 47PFL5604H backlight/inverter

Where did you find element values?

I am looking also for D303 and D908 values. D303 has marking "5D" that is all i know.

[xiribitu]

Re: [Philips TV] 47PFL5604H backlight/inverter

Replaced Q301A and Q301B (P10NK60ZFP) with P12NM50FP as didn't find exactly the same part. Also replaced R344 with 0.2ohm resistor.

Hi, my TV has the same syptoms, everything works but no backlight. Replaced those parts you mentioned (shorted fets and opened resistor) but still no luck.
Did you find what's causing the problem?

[felix]

Re: [Philips TV] 47PFL5604H backlight/inverter

Hello,

I have same TV but it doesn't power on, not even standby led.

I have measured the SB260 Diodes (D907 & D911) but they are ok (0.210V on DMM diode test, out of circuit).

The only thing i managed to find is the Optoisolator PC902, which input is connected to "FAULT" pin 17 of IC702 (DDA003A) and input pins 1&2 of DDA005.

PC902 is NEC-PS2561B-1-A, and i do not get any sign from pins 1&2 (internal led Anode and Cathode) when measuring with DMM in diode mode.

Can anyone enlighten me ? What has happened there ?

I believe that DDA003A is responsible for inverter UCP and BL dimming ? Counld my problem be caused by that ?

I have no other shorted element, but i haven't measured the caps ESR out of circuit. Is there any problem with the specific PSU and the caps in the past?

Thank you in advance !

[felix]

Re: [Philips TV] 47PFL5604H backlight/inverter

I took some measurements with the PSU connected on AC.

On CN4 Connector i get no 3.3VSB.

IC901 (3BS3LJ)
Pin 7 (VCC) cycles between 11 and 17volts
Pin 4 (HV) is stable at 270 Volts

IC4 (DDA005)
Pin 2 (IN) starts from 21.6 Volts and falling with steady step (measured up to 20 Volts)
Pin 4 (OUT) is 0

On R916 close to IC901 i also get 11-17 Volts cycling.


Without AC connected :

On D908 close to IC901 i measure 0.062V in DMM diode mode, in both directions.
On D903 i measure 0.175V, the same with above.

Is IC4 my problem, since there is no VCC-ON voltage ?


Thank you in advance