Philips 42PFL7403D Doesnt turn on

**ben7** · 08-06-2012, 02:51 PM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by pacmyc

Philips LCD 42 inch TV (42PFL7403D/10)
Chassis Q529 1E LA.

TV only power on sometimes. I cant find any bad caps on the power supply.

When TV is connected to mains moste of the time nothing happens. When pressing buttons on remote control the red led on the front side flashes shortly once each time i press a button.

I checked the voltages on the PSU, and I got nothing except on the standby 3.3V. It was "flashing" (cheap multimeter) between 3.06 V - 3.25 V (service manual says should be 3.3 V). When pressing a button on the remote control the standby voltage drops to about 2,6 V for about a second, and then goes back to 3.06 - 3.25 V.

The TV seems to start fine in the morning but not in the evening!?
Also when I disconnect TV from mains I get a small chock if I touch the power cable withing 10 seconds.

The PSU has number 310432852762.

I cant attach servicemanual due to too large filesize, but it's downloadable from here http://elektrotanya.com/philips_chas.../download.html

You get a shock from the cable? dam! thats VERY dangerous!

I think there must be something VERY wrong with the PFC circuits on your PSU!

pics?

**pacmyc** · 08-07-2012, 10:22 AM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by ben7

You get a shock from the cable? dam! thats VERY dangerous!

I think there must be something VERY wrong with the PFC circuits on your PSU!

pics?

Well, I survived

See attached pics.

Attached Files

**selldoor** · 08-07-2012, 10:56 AM

Re: Philips 42PFL7403D Doesnt turn on

Couple of things - Transformer top left in pic one looks cracked in half - is it loose?
Id change the 3 small caps in the primary(hot) section 2 blue and one green
one is likely to be the startup cap. If it is the one between the heatsinks it will be well cooked.

**pacmyc** · 08-07-2012, 11:39 AM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by selldoor

Couple of things - Transformer top left in pic one looks cracked in half - is it loose?
Id change the 3 small caps in the primary(hot) section 2 blue and one green
one is likely to be the startup cap. If it is the one between the heatsinks it will be well cooked.

Allright, you mean these right?
Well, if you think it's worth a try I'll do it.
What about the pending (jumping) standby voltage (3.1V-3.2V) ?

Attached Files

**pacmyc** · 08-07-2012, 01:20 PM

Re: Philips 42PFL7403D Doesnt turn on

When replacing cap 2105 the service manual say says in the
print 47 uF 50V, but in the replace part list it says 22uF 50V, and
the old cap is a 100 uF 25 V!

Is it OK to replace a 100uF 25V with a 47 uF 50 V?

**selldoor** · 08-07-2012, 01:28 PM

Re: Philips 42PFL7403D Doesnt turn on

If the cap you are replacing looks like an original factory fitted then you should fit the same. If not it is than a bit of a problem. Could anyone have messed with it?

It is usually possible to go to a step higher uf and a step higher voltage without ill effects but never go lower on uf or voltage.

I"s it OK to replace a 100uF 25V with a 47 uF 50 V? " - No

**ben7** · 08-07-2012, 01:33 PM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by selldoor

If the cap you are replacing looks like an original factory fitted then you should fit the same. If not it is than a bit of a problem. Could anyone have messed with it?

It is usually possible to go to a step higher uf and a step higher voltage without ill effects but never go lower on uf or voltage.

I"s it OK to replace a 100uF 25V with a 47 uF 50 V? " - No

Well, If it is in the startup circuit, then a larger cap will make it take much longer to turn on.

I'd check for voltage on that big black capacitor in the middle. It should be about 165v (cap is rated for 200v)

**pacmyc** · 08-07-2012, 01:52 PM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by selldoor

Couple of things - Transformer top left in pic one looks cracked in half - is it loose?
Id change the 3 small caps in the primary(hot) section 2 blue and one green
one is likely to be the startup cap. If it is the one between the heatsinks it will be well cooked.

The transformer seems fine. Not loose at all.
I have now replaced the three caps as you suggested, problem remain.

**pacmyc** · 08-07-2012, 01:54 PM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by ben7

Well, If it is in the startup circuit, then a larger cap will make it take much longer to turn on.

I'd check for voltage on that big black capacitor in the middle. It should be about 165v (cap is rated for 200v)

OK. How do you suggest that I measure it?
Should I solder a cable under the backside of the PSU on the + side of the cap and measure voltage to ground while trying to start the TV ?

**pacmyc** · 08-07-2012, 01:56 PM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by selldoor

If the cap you are replacing looks like an original factory fitted then you should fit the same. If not it is than a bit of a problem. Could anyone have messed with it?

It is usually possible to go to a step higher uf and a step higher voltage without ill effects but never go lower on uf or voltage.

I"s it OK to replace a 100uF 25V with a 47 uF 50 V? " - No

OK, thanks for quick answer.
Yes it really looked like a factory fit, it was also of the same brand as other caps on the board. Finnaly I found a cap with the same F and V and replaced it. However still the same problem.

**selldoor** · 08-07-2012, 02:03 PM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by ben7

I'd check for voltage on that big black capacitor in the middle. It should be about 165v (cap is rated for 200v)

Hmm! careful high voltage Ben7 have you remembered that OP is in Stockholm mains voltage is 230VAC - cant get my brain around why cap is only 200.

OP - was this an import from US does it run on a voltage adapter?

**pacmyc** · 08-07-2012, 02:10 PM

Re: Philips 42PFL7403D Doesnt turn on

Originally posted by selldoor

Hmm! careful high voltage Ben7 have you remembered that OP is in Stockholm mains voltage is 230VAC - cant get my brain around why cap is only 200.

OP - was this an import from US does it run on a voltage adapter?

No it's sold in Sweden. It's rated 220-240 V 50-60 Hz.
In the service manual it also says 200 V on this cap.

**pacmyc** · 08-07-2012, 02:12 PM

Re: Philips 42PFL7403D Doesnt turn on

Also, I forgot to tell in the first post. I get some voltage on the PSON on the PSU (It's pendnig quickly (flashing on my cheap digital multimeter) between 0.8 - 2.5 V.. (Connector 1M95)
And also about 0.3 V on BL-ON (connector 1M99)

Also, I cant hear any relea switching when mains are connected (neither when the TV is working nor its not)

**pacmyc** · 08-08-2012, 10:50 AM

Re: Philips 42PFL7403D Doesnt turn on

Update: Sometimes when I connect the powercord to the TV the red led on the front flashes twice. According to the sm this is a SSB error. I will try to get the set in SDM mode to get the layer2 fault-code.

**pacmyc** · 08-09-2012, 10:02 AM

Re: Philips 42PFL7403D Doesnt turn on

When cable on connector 1M95 id disconnected I get 3.4 steady voltage on 3v3 standby out from PSU. Also the 12 V supplies goes up for half a second, then they are shut down. Standby voltage remains.

**pacmyc** · 08-09-2012, 12:15 PM

Re: Philips 42PFL7403D Doesnt turn on, breakthrough or not!??

UPDATE:
PSU starts up just fine if I just disconnect the LED panel control from the SSB. (connector 1M20 on picture).
Stable 3.4 V (standby 3V3) and stable 12V. After about 10 seconds PSU shuts down the 12 V but continoes to deliver standby 3.4 V.
How is this possible? Could there be a short some where in the led panel control?
Attached schematics for led panel control + pics.

Attached Files

**selldoor** · 08-09-2012, 12:38 PM

Re: Philips 42PFL7403D Doesnt turn on, breakthrough or not!??

Originally posted by pacmyc

UPDATE:
Could there be a short some where in the led panel control?

Yes there has been a one found in that last few days cant remember if it was a short or an open but totally messed with the whole tv.
I think it was in desperation that he/she ohmed out the led cable and found it.

**pacmyc** · 08-09-2012, 12:41 PM

Re: Philips 42PFL7403D Doesnt turn on, breakthrough or not!??

Originally posted by selldoor

Yes there has been a one found in that last few days cant remember if it was a short or an open but totally messed with the whole tv.
I think it was in desperation that he/she ohmed out the led cable and found it.

So I guess I can now rule out that it is PSU / and or SSB that is not working right?

Is there anything I can do with the led panel control to fix it (its 2 layers, and damn small components) or should I start asking around for a replacement board?

**pacmyc** · 08-09-2012, 12:50 PM

Re: Philips 42PFL7403D Doesnt turn on

Just got the TV working!
I connect the mains with the led panel control disconnected.
Then I slowly press down the cable into the connector, and there it goes, starts working. TV is on, everything works great.. But if i turn it off I'll have to disconnect the led panel control to get the TV on again.. :S

Philips 42PFL7403D Doesnt turn on

Philips 42PFL7403D Doesnt turn on

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