Philips 42 lcd no power

[sienoki]

Hey up people..got a philips 42pfl3606h/12 lcd with a 715G4802-P01-H20-003H Z side PSU..this set displays no sign of life..no led on front..no backlight..no nothing
On the main pinout im getting the +5v readings & the DIM readings but no others..no 12v/24v or S/B
The main fuse checks ok..the main cap reads short of 400v...ive not been able to find any schematics or fault findings on the net so any help with diagnosis & testing would be gratefully received..thx

[sienoki]

Re: Philips 42 lcd no power

Hey up people..got a philips 42pfl3606h/12 lcd with a 715G4802-P01-H20-003H Z side PSU..this set displays no sign of life..no led on front..no backlight..no nothing
On the main pinout im getting the +5v readings & the DIM readings but no others..no 12v/24v or S/B
The main fuse checks ok..the main cap reads short of 400v...ive not been able to find any schematics or fault findings on the net so any help with diagnosis & testing would be gratefully received..thx

Some underside pics of PSU..thx

[selldoor]

Re: Philips 42 lcd no power

Hi - can we have a pic of the main board - Is this a LED backlight?
Backs of PS board are not really clear enough for troubleshooting cant read all the numbers. Were voltages taken with boards screwed in - there have been a few stories recently where boards were not grounded correctly. Also were they all connected up and with a source - video playing - was there any Audio.
Try unpluging the lead from the main board to the panel (or tcon) and see if that lets the voltages come up.

[tom66]

Re: Philips 42 lcd no power

Checks:

- Separate fuse for main PSU? (Fusible resistor etc...?)
- Shorted diodes on output
- Any power LED behaviour change
- PSON good
- Ticking etc. from PSU

Replace

- Startup cap no question, it is cheap and can cause the problem

[awyatt2]

Re: Philips 42 lcd no power

i just fixed one of these two caps small i think 10 and 47 uf at 35 v, on the 12v and 24v rail and a bad solder ring on the board where the 24v line plugs in. know its not all the same on every tv but i would look at thr connector to be sure. the 2 caps were over 20 ohms esr.

[sienoki]

Re: Philips 42 lcd no power

i just fixed one of these two caps small i think 10 and 47 uf at 35 v, on the 12v and 24v rail and a bad solder ring on the board where the 24v line plugs in. know its not all the same on every tv but i would look at thr connector to be sure. the 2 caps were over 20 ohms esr.

Got the jewellers eye out & found a few dry joints so applied fresh solder..the main fuse in the holder was sparking when moving end of power plug so re-soldered them points & all is good...thx for input guys

[tom66]

Re: Philips 42 lcd no power

Got the jewellers eye out & found a few dry joints so applied fresh solder..the main fuse in the holder was sparking when moving end of power plug so re-soldered them points & all is good...thx for input guys

Really, just some cold joints? That has to go down as one of the easiest fixes I've seen here... Where did you get the set?

[awyatt2]

Re: Philips 42 lcd no power

seen quite a few phillips latley with bad solder rings. the power supply he has here is the same type i fixed yesterday. the two small startup caps were bad but the solder joints was the problem.

[sienoki]

Re: Philips 42 lcd no power

seen quite a few phillips latley with bad solder rings. the power supply he has here is the same type i fixed yesterday. the two small startup caps were bad but the solder joints was the problem.

This set has not been totally fixed as my m8 just rang saying its gone off again so im gonna check the board over again & do what awyatt2 did

[sienoki]

Re: Philips 42 lcd no power

This set has not been totally fixed as my m8 just rang saying its gone off again so im gonna check the board over again & do what awyatt2 did

Ive replaced the small value caps & still no joy..i spent half hr plugging on & off & resoldering half of the psu..then eventually back to life again..should i replace the 1000uf caps?..ive no esr meter to measure their value & they not bulged..thx
If the 1000uf caps are low will it cause these symtoms?..the set is not even 1yr old!!

[selldoor]

Re: Philips 42 lcd no power

I would not celebrate too soon - I have been caught out before thinking I had fixed something - replaced some caps re soldered joints and it worked great
left it on testing as I thought and yes it worked flawlessly.
UNTIL it cooled down - eventually traced to a couple of caps, not replaced, that were fine when warm but when cooled - dead.

[sienoki]

Re: Philips 42 lcd no power

I would not celebrate too soon - I have been caught out before thinking I had fixed something - replaced some caps re soldered joints and it worked great
left it on testing as I thought and yes it worked flawlessly.
UNTIL it cooled down - eventually traced to a couple of caps, not replaced, that were fine when warm but when cooled - dead.

I will recap the psu with panasonics & see how it goes..thx

[sienoki]

Re: Philips 42 lcd no power

I will recap the psu with panasonics & see how it goes..thx

This set worked flawless last night..been left off 10hrs & fired straight on this morning..can i say this set is fixed? or would you bother with the 1000uf caps?..thx

[tom66]

Re: Philips 42 lcd no power

This set worked flawless last night..been left off 10hrs & fired straight on this morning..can i say this set is fixed? or would you bother with the 1000uf caps?..thx

I would look closely at the power to the inverter for cold joints and the side button panel.

What caps are used in this set?

[sienoki]

Re: Philips 42 lcd no power

I would look closely at the power to the inverter for cold joints and the side button panel.

What caps are used in this set?

Theres 10 caps on this psu..7 ELITE brown & 3 SAMXON green..the elites ive changed with panasonic apart from 3 1000uf & 1 470uf..ive resoldered all the transformers & box caps etc but left the small smd stuff for now

[selldoor]

Re: Philips 42 lcd no power

If I was keeping it for my own use I would probably leave it but as you know elite caps are not great so as it is for someone else I would change them.
At least if it stops again you will know that is not the problem.