Philips 42PFL3605H/12 Power on and off cycle

[g3org3]

Hi Guys,

I need your help with my TV. So far I replaced Caps on both boards(even when tested good - used atlas ESR), Checked PSU transformers with blue ring tester, Check all diodes, resistors and mosfets with Atlas DCA pro, But I cannot find anything wrong with this PSU. When I plug the power and turn the TV on it will stay on for about 1 min then it will shut itself off and then after about 30 seconds it will turn on and then shut off again. Checked regulators on main board also fine. I think it's the PSU since I am getting a buzzing sound where the inverter is.....Any ideas and help will be very much appreciated. This is my 1st post so please correct me if I did something wrong.

[comptek]

Re: Philips 42PFL3605H/12 Power on and off cycle

check lamp connections "DO NOT HAVE IT RUNNING WHILST DOING THIS"
could be one of the lamps failed

[g3org3]

Re: Philips 42PFL3605H/12 Power on and off cycle

both lamps do come on. When the power is on for the 1 minute the picture on the screen is fine. Is there any other test I can do on the lamps?

[g3org3]

Re: Philips 42PFL3605H/12 Power on and off cycle

Uploading better quality pics

[g3org3]

Re: Philips 42PFL3605H/12 Power on and off cycle

Any ideas?

[thoma]

Re: Philips 42PFL3605H/12 Power on and off cycle

It is a TPM 5.1 Chassis
There are a lot of problems with D921 in SMPS RECTIFIER SR515
-
08 X0 5A 150V DO
-
201AD

When the tv goes to stand by or is rebooting On the SSB replace item U753!

Thats all I know hope it will help!
regards thoma!

[g3org3]

Re: Philips 42PFL3605H/12 Power on and off cycle

thoma thank you very much for the input.. both on order, will update

[g3org3]

Re: Philips 42PFL3605H/12 Power on and off cycle

Hi Guys,

Replaced both D921 ans D922 ,replaced U753 on SSB and still no lack.

Added a 0.1uF across IC804 and that stopped the buzzing on the T802 (inverter).

I am attaching the service manual maybe someone can see something i cant?

voltages are ok 5-> 5.3
12->12.03
24->25.6

If i turn the TV on and then power it off from the power button i do have the 5v with no issues. any help will be very much appreciated

[budm]

Re: Philips 42PFL3605H/12 Power on and off cycle

Hi Guys,

Replaced both D921 ans D922 ,replaced U753 on SSB and still no lack.

Added a 0.1uF across IC804 and that stopped the buzzing on the T802 (inverter).

I am attaching the service manual maybe someone can see something i cant?

voltages are ok 5-> 5.3
12->12.03
24->25.6

If i turn the TV on and then power it off from the power button i do have the 5v with no issues. any help will be very much appreciated

I am a little confused, you indicated that the TV power cycle itself, are you saying that the 5VSTBY is steady but the switched 12V/24V (which are turned on the by PS-ON signal from the main board) disappear?
I extract the power supply-inverter section from the service manual.

[g3org3]

Re: Philips 42PFL3605H/12 Power on and off cycle

the 5VSTBY is steady only when I shut the TV off. When the TV shuts it self off it's not there, all voltages are gone, then after about 2 mins the power is back and the TV turns on itself...

[budm]

Re: Philips 42PFL3605H/12 Power on and off cycle

the 5VSTBY is steady only when I shut the TV off. When the TV shuts it self off it's not there, all voltages are gone, then after about 2 mins the power is back and the TV turns on itself...

If that is the case then you need to work in the standby power supply section.
When standby Voltage drops out then it will cause everything else to shutdown.
Look at solder joints, check rectifier and caps, etc. Standby supply has to be there at all time.

[g3org3]

Re: Philips 42PFL3605H/12 Power on and off cycle

SG6961SZ replaced issue resolved.... :-) Thank you all for your help

[Necrogimp]

Re: Philips 42PFL3605H/12 Power on and off cycle

Hi how did you checked the SG6961SZ component ? I have the same issue I just want to check the component as you did before ordering online the component