Philips 42PF3320/10 plasma white flashing

[IMBack!]

Hi I have a Philips Philips 42 SD v4 plasma tv 2005 vintage, i dont know its history.

Its fault is as follows

At first:

1. tv turns on flickers at aprox 1hz allmost white then black (see video).
2. all rails are pressend and voltages are correct but there is alot of ripple (see picture 1 and picture 2) during the blink "on" phase on all rails, even the 5v and 3.3v logic rails.
3. This ripple dissapears when the Y sustain is detached.

Than sunndenly while measureing the voltages with just the x sustain attached somithing happend, sound made by the unit changed, a ployfuse on the power supply triggerd. No short was created by me.

Now:

1. If the X sustain is attached ve, vs go to 0v polyfuse triggers
2. if x sustain is dettached everything is like before.

what now?

Addtitionally attached is a table with the measured voltages in different stages.

[IMBack!]

Re: Philips 42 SD v4 plasma tv

Actually the ripple is quite bad when every thing is unplugged from the power bord. Ho mutch ripple is acepatable on vs?

[IMBack!]

Re: Philips 42 SD v4 plasma tv

Is some piece of information missing? the service manual identifys the tv as "42SD v4"

the marketing name is 42PF3320/10

the pannel and all major boards are samsung in origin.

[IMBack!]

Re: Philips 42 SD v4 plasma tv

Well the x-board hat a blown fet. its in order again. dosent solve the other issue thogh

[IMBack!]

Re: Philips 42 SD v4 plasma tv

I have switched the IPMS's on the y board with those on the X-board. the problem has not changed.

If the logic flex cable to the Yboard is disconnected the voltages stabilze and a ysutain wave can be seen on the test points on the buffer boards. otherwise the ybaord cycels

also a buzzing sound from the y board can always be heard

[IMBack!]

Re: Philips 42 SD v4 plasma tv

attached images:

1. Both y testpoints on buffer, shown on scope.
2. Y board
3-4. Y buffer.

[IMBack!]

Re: Philips 42 SD v4 plasma tv

I tryed to measure Vsch. But i cant find it.

The attached picture shows the Y-sustain connectors to the buffer.

All the red highlighted pins are connected together. All the Yellow highlighted pins are also connected together.

There is no voltage or waveform of any kind between the yellow and red pins nor is there any voltage betwen the blue pin and the other pins.

all pins have a aprox +-200v square(ish) wave on them to ground.

shloud Vsch be found between the red an the yellow pins? if no where is it found? If Vsch shloud be there what fault on the y-board might cause it to be missing?

[IMBack!]

Re: Philips 42PF3320/10 plasma white flashing

anyone?

[tw2005]

Re: Philips 42PF3320/10 plasma white flashing

can't help with the fault finding but there's a test pad marked VSCH to the left of R5135 and above D5020 near where that yellow transformer and large electrolytic cap is as you have the photo of the ymain orientated .

[tw2005]

Re: Philips 42PF3320/10 plasma white flashing

what's going on with D5005 (unmounted from the heatsink) and the other D5004 with the screw half hanging out?

[tw2005]

Re: Philips 42 SD v4 plasma tv

I have switched the IPMS's on the y board with those on the X-board. the problem has not changed.

If the logic flex cable to the Yboard is disconnected the voltages stabilze and a ysutain wave can be seen on the test points on the buffer boards. otherwise the ybaord cycels

also a buzzing sound from the y board can always be heard

IPMSs? I dont see any IPMs if your talking integrated power modules?

[IMBack!]

Re: Philips 42PF3320/10 plasma white flashing

ipms i ment d5005 and d5004. i need to resolder those they don't align with the heatsink. but they aren't getting very hot in the 1 minute test cycles im doing (tested with temp probe).

[IMBack!]

Re: Philips 42PF3320/10 plasma white flashing

Found somthing.

5v VCC is conneced to the yellow highlighted pin, but only 0.38v are present.

The regulator in red is responisble for VCC. It works, i powerd it up with a lab power supplya and a 0.5a load. According to its datasheet it needs 8-12V on the input pin. Its getting 0.5v.

Im tying to find where the input pin is connected to, the last point i can trace it to is highlighted in green. its a 4 layer board and i dont know where it goes after that. any hints?

[IMBack!]

Re: Philips 42PF3320/10 plasma white flashing

can't help with the fault finding but there's a test pad marked VSCH to the left of R5135 and above D5020 near where that yellow transformer and large electrolytic cap is as you have the photo of the ymain orientated .

Vsch is bang on at 140v so thats not it, thanks for the test point. you have good eyes.

I also made a mutch clearer picture of the ysus board.

[IMBack!]

Re: Philips 42PF3320/10 plasma white flashing

well looks like the regulator U5012 (highlighted red) is suplying the 5v reg. its input lead and ground are shorted (highlighted yellow) but its fine out of circut. it seams to be directly connected to the transformer t5001.. its a dc-dc regulator this makes no sense

I think t5001 might be bad, how do find a replace ment? what dose w3-13t mean?

[vicvc]

Re: Philips 42PF3320/10 plasma white flashing

u5012 is a 15v reg not 5.c5040(elec) to gnd(to the left on your pic).d5019 and r5134 to t5001

[IMBack!]

Re: Philips 42PF3320/10 plasma white flashing

oh crap. while trying to remove the tansformer, to see the traces underneath, i broke 2 leads . I cant find a datasheet or anything on the transformer, it looks like this board is a gohner.

u5012 is a 15v reg not 5.c5040(elec) to gnd(to the left on your pic).d5019 and r5134 to t5001

yes i know i was refering to that the 15v output of u5012 drives u5010 witch supplys the missing 5v rail to the buffer.