Philips 42PFL9603H chassis Q529.1E LA wont power on

[jbfr_54]

Hi All,
I have a problem of powering this set. When pluging main's cord, the light guide (center bottom LED) flashes during a few seconds then nothing else happens.
The red standby light is off and te remote does not operate. Pushing the Power button on side keyboard does the same. Still no Stdby LED !
I verified all the power supplies from the PSU and inside the SSB board, they seem to be OK (using voltmeter and oscilloscope).
When I electrically touch around DC/DC converters of the SSB board, using the Power button allows sometimes the set to Start and run normally. I discovered that possibility accidentally ! In that case, the set being working normally, if I turn it off to standby using the RC, the set stops and the red LED is ON indicating Standby status. In such case I can restart and stop the set using the RC without any fail as many time as I wish.

From the working status or the Stdby status, if I unplug the main's cord, the set recovers normally when the cord is plugged back.

If, from the Standby status (red LED ON) I push the Power key, the sets shuts off the standby status to go to POWER OFF status, red LED going off as expected.
At this point, I cannot restart the set as described at begining.
It seems that from the POWER OFF status, I cannot swith to STANDBY STATUS.

I updated to the latest firmware, check the option codes in the Service Menu, no change in behavior.

Any idea ?
Regards.
Jean

[jbfr_54]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Hi Guys,
No one has ever fixed this set or this type of problem ?
Please help !
Regards.
Jean

[jbfr_54]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Hi All,
Just in case someone gets interested in this case later !

I finally solved the problem which was due to a lack of power on the 3.3 v stdby supply. When hitting the Power switch, the 3.3v stby supply was droping down to 3.15v (3.4v during normal operation). This was detected by the 7HD0 IC (NCP303LSN30) thus generating an undue Reset-stdby signal which is supposed to happen only at mains plugging. The resest-stdby signal was forcing the controler to remain at the Off state instead of going to Standby status when pushing the power on button.
The 3.3vstandby power line is generated separately than the other supplies in the PSU. It's circuit is powered by the main line through two caps in parallel (100 + 22nF) labeled 2165 and 2179. Their values were 67 and 17 nFarad respectively. Replaced by a new MKP 0.12uF has solved the problem.

The tricky thing is that the 3.3vstdby supply was OK when set was either working or in standby and only droping when pushing the Power button.

Hope this ca help someone as I spent hours of intensive search for this problem.

Regards.
Jean

[majortom]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Hi All,
Just in case someone gets interested in this case later !

I finally solved the problem which was due to a lack of power on the 3.3 v stdby supply. When hitting the Power switch, the 3.3v stby supply was droping down to 3.15v (3.4v during normal operation). This was detected by the 7HD0 IC (NCP303LSN30) thus generating an undue Reset-stdby signal which is supposed to happen only at mains plugging. The resest-stdby signal was forcing the controler to remain at the Off state instead of going to Standby status when pushing the power on button.
The 3.3vstandby power line is generated separately than the other supplies in the PSU. It's circuit is powered by the main line through two caps in parallel (100 + 22nF) labeled 2165 and 2179. Their values were 67 and 17 nFarad respectively. Replaced by a new MKP 0.12uF has solved the problem.

The tricky thing is that the 3.3vstdby supply was OK when set was either working or in standby and only droping when pushing the Power button.

Hope this ca help someone as I spent hours of intensive search for this problem.

Regards.
Jean

would never have thought about it . many thanks

[acinfo64]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Thank you very much! It was exactly what I was looking for, thanks!

[jbfr_54]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Glad it helped !

[budm]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

There is similar bulletin on these caps.

[jbfr_54]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Well, if I had that on hand, it would have saved me a lot of search time ! Thanks for this added information.
Jean

[N-P-Rhodes]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Well this thread did the trick! Thanks guys! I followed the instructions in the .pdf above. The components cost me just around 5 DKK = £0.50 = $0.75. Postage was 12 times this amount! Removed the existing caps and replaced with the new ones. TV worked first time! Certainly cheaper than buying a new one. Thanks again everyone.

[chini7236]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Thank you very much! It was exactly what I was looking for, is the fault I had, thank you very much

[Gil]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Thank you very much!

[alekosrepair]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Another successful repair, thank you very much guys!

[Moost]

Re: Philips 42PFL9603H chassis Q529.1E LA wont power on

Thank you very much! As discribed in the posted PDF I replaced the capacitor 2165 from 22nF (it had only 18nF) to a 47nF and the capacitor 2179 (it had only 56nF) to a new 100nF.

Now the TV works perfectly again!