Philips 42PFL7422D/37 is dead

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

Am I missing anything? The problem states that he has 120 in to the power board's bridge rectifier and nothing coming out from the bridge rectifier. CHANGE THE RECTIFIER - or did you measure this wrong?

The rectifier, I have checked already twice and it checks out good.

[budm]

Re: Philips 42PFL7422D/37 is dead

That cap on the main board should have 170VDC when you plug the TV into the outlet. Does the fuse check OK?
It just has AC coming in to feed the fuse, then the bridge and the cap, that is.

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

There is the supply cable that I have unplugged on the main PS and I forgot where should be connected.
There are two possible connections, I'm using the black connector on the board.
It's been a while since I have opened up this TV and I forgot from where I have unplugged it.
The fuse is good, that resistor (FB) is good also.
On the supply wires I'm not getting 170V either. So the problem must be at the main PS.

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

What are those two white ceramic parts on tHe PS board? Resistors of high wattage? I measure values in MOHMs. These are going to the IP02 connector.

[budm]

Re: Philips 42PFL7422D/37 is dead

If you look under those two white ceramic parts, there are two jumpers installed as I see in your picture.

[budm]

Re: Philips 42PFL7422D/37 is dead

Are there jumpers?

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

I'm getting some fluctuating milivolts.

[budm]

Re: Philips 42PFL7422D/37 is dead

Please see my edit post 26. It sounds like there is an open circuit to the IP02 connector.
They look like to be 1 Ohm resistors in parallel.

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

I have resoldered both transformers and both big resistors. No change. Maybe those resistors are bad? One measures around 30Mohms and the other around 10. They are not showing a constant value. Just before the resistors I have 0.4Ohm.

[budm]

Re: Philips 42PFL7422D/37 is dead

So no jumpers, if that is the case, those two big resistors are open, which means it may be feeding shorted circuits somewhere.
Those two resistors also feed the relay, the output of the relay feed the bridge rectifier 6307/TS6B, so you may have shi=orted bridge and any components that are fed by the output of the bridge, please see the diagram I had attached, so there are many components to check for shorted. Those two resistors are used as fusible resistors.
"One measures around 30Mohms and the other around 10." That does not make sense, they are in PARALLEL.

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

There are no jumpers, you are right. It's weird, why it would be a jumper there when there are some resistors?
Today before I left from home, I have removed the ceramic resistors and one it's open and the other showing something like 49 MOhm and it's not a constant number, so that one is blown.
I see in the schematic and you pointed out that they are 1 Ohm resistors, but how do we find out there wattage?

[budm]

Re: Philips 42PFL7422D/37 is dead

I believe you have shorted circuit in you baord that cause the two fusible resistor to blow open. I would look for shorts first.

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

The rectifier is good, I have checked it already twice. What else should I check? Everything which is on your red line?

[budm]

Re: Philips 42PFL7422D/37 is dead

If you look at the PDF of the diagram on the second page, the output of the bridge 6307 (400V output) feed the MOSFET 7005, 7006 for driving the power transformer.

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

I have taken apart both resistors and they still conduct(wires only) after cleaning the ends. They show 1.6 Ohm.
What do you think this will work?
http://www.digikey.com/product-detai...591-ND/2365105

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

Those two transistors are good.
I have a feeling that these resistors had some bad connections inside them because of the heat. Probably they were oxidized.

[budm]

Re: Philips 42PFL7422D/37 is dead

If you are sure that no shorts are found, then use that lamp setup, you will need 200W for this TV, you can use may be 5A fuse in place of the resistor and see if it will power up OK.

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

I don't have a 200W bulb or a 5A fuse.
I would rather buy the resistors instead, but I'm not sure which one?
Do you think that those above are fine?
I can also use some how the wires from the resistors too. Just not sure how can I make good contact between the resistor wire and PCB. If I'm correct, these resistor wires are steel and can not be soldered.

[tom66]

Re: Philips 42PFL7422D/37 is dead

In standby, 100W is fine.

Inverter may even try to fire up but will quickly shut down.

Two 100W bulbs in parallel ~= one 200W bulb.

[tibimakai]

Re: Philips 42PFL7422D/37 is dead

I don't have the right setup now to connect two 100W bulbs. I think I have a higher wattage bulb, which makes heat, but I don't remember the wattage.
The question is how to connect the resistor wires to the PCB? Should I try to solder them? I will probably wind it back on a pencil and I will try to solder them.