Philips 37PF7321/98 cannot turn on

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

Thats a fine picture! you can dream of more testing tomorrow. Now we can see there will be lots - perhaps start with the diode near the legs of the mosfet just above the "K"
Good night.

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

Going back to budms post re resistor 3318 Whilst the resistance is ok can you check out
the soldering on it. Another thread has flagged it up as a problem area so may be worth a look.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

Going back to budms post re resistor 3318 Whilst the resistance is ok can you check out
the soldering on it. Another thread has flagged it up as a problem area so may be worth a look.

I do not think that 3318 on the power supply is a factor right now since we can get the power supply to turn on and give us stable voltages out at the dc side

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

I do not think that 3318 on the power supply is a factor right now since we can get the power supply to turn on and give us stable voltages out at the dc side

Ok - I thought I read that it was significant in getting the backlights on.

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

Thats a fine picture! you can dream of more testing tomorrow. Now we can see there will be lots - perhaps start with the diode near the legs of the mosfet just above the "K"
Good night.

I have checked the zener diode 6531. There is 0.7v in the direction of pin 3 to pin 1 of mosfet 7531. I am measuring in-circuit, don't know is it correct. The opposite direction is OL. Looks like 6531 is ok.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

more to check on this non switching issue

we know red Gnd is ok ground
can you check the other 5 red circle for ground or not ground

recheck 5v ok at the transistor yellow D
and double check to make sure 5v is still not on the yellow S pin
also check for possible voltage to the yellow G pin and yellow B pin at the smaller transistor and small blue circle at the top of the picture

and , if I could get another pretty picture like this from the top of this area to and including the 11 and 10 pin connectors, that may become useful

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

^^^^^^ Picture to go with this?^^^^^^^^

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

What, no x-ray vision !!??

john is probably in bed right now having dreams of this thing !!

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

more to check on this non switching issue

we know red Gnd is ok ground
can you check the other 5 red circle for ground or not ground

recheck 5v ok at the transistor yellow D
and double check to make sure 5v is still not on the yellow S pin
also check for possible voltage to the yellow G pin and yellow B pin at the smaller transistor and small blue circle at the top of the picture

and , if I could get another pretty picture like this from the top of this area to and including the 11 and 10 pin connectors, that may become useful

Red circle 1 and 3 are 5v
Pin 2 of 1305 is 5v, all3 pins of 1305 are 5v
Red circle 4 and 5 are 0v

Yellow D is 5v. Yellow S is 0v. Yellow G is 0v. Yellow B and E are 0v. Yellow C is 5v. Blue small circle is 0v.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

all 3 pins on 1305 is 5 volts !!
Well that doesn't right
we should have a 5v and a ground
do you have the 3 pin wire to the power supply connected ?

I also need to know if any of the zero voltage ones grounded
turn off power
and check them with the ohm setting

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

all 3 pins on 1305 is 5 volts !!
Well that doesn't right
we should have a 5v and a ground
do you have the 3 pin wire to the power supply connected ?

I also need to know if any of the zero voltage ones grounded
turn off power
and check them with the ohm setting

Yes, 3 pin wire 1305 is connected to the power supply board.

Red circle 4 and yellow E are ground.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

Yes, 3 pin wire 1305 is connected to the power supply board.

Red circle 4 and yellow E are ground.

disconnect the 3 pin wire and recheck those 3 pins for dc and ground

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

disconnect the 3 pin wire and recheck those 3 pins for dc and ground

None is ground.

When I power up with 1305 disconnected, all 3 pins are still 5v.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

well, I am lost
I have no idea how 5 volts is magically showing up on pin 3 of the 1305 connector with no wire attached and since the transistor pins at the yellow B pin shows no voltage and the yellow E is a ground

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

Well I will keep you company
Right ive already admitted I know very little about tvs in general and dont understand this one at all so I just want to throw in this idea, but am happy for it to be shot down in flames. I think we have been looking at the relay as something to switch on the 240v line ( for the inverter section?). I am now wondering if it is part of the protection
(see labels on the block diagram by 1305) So if something is tripping the protection ( By the way have you tried it with the lamps connected - if not that could be a "fault") then perhaps that 5v keeps it switched off.
Ill leave that in but will flame myself as im sure you have tried to fire it up with the connector to the relay unplugged.

Also note the label on the block diagram that says Standby --- Low = ON High =OFF
( I have no real idea what that means unless it means you have to pull pson to low to get it to switch on.)

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

even if we need to pull , say pin 3 5volt to ground which could be possibly done with the small transistor that is to the left of it -- Where the hell is that 5 on that pin coming from in he first place ??
if he had the wire connected to the power supply, then it could be coming through the relays coil, but that wire is disconnected !

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

even if we need to pull , say pin 3 5volt to ground which could be possibly done with the small transistor that is to the left of it -- Where the hell is that 5 on that pin coming from in he first place ??
if he had the wire connected to the power supply, then it could be coming through the relays coil, but that wire is disconnected !

Bammbammfran - if you want to call it quit, I will understand. You have already spent many hrs/days on my problem.

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

Well I will keep you company
Right ive already admitted I know very little about tvs in general and dont understand this one at all so I just want to throw in this idea, but am happy for it to be shot down in flames. I think we have been looking at the relay as something to switch on the 240v line ( for the inverter section?). I am now wondering if it is part of the protection
(see labels on the block diagram by 1305) So if something is tripping the protection ( By the way have you tried it with the lamps connected - if not that could be a "fault") then perhaps that 5v keeps it switched off.
Ill leave that in but will flame myself as im sure you have tried to fire it up with the connector to the relay unplugged.

Also note the label on the block diagram that says Standby --- Low = ON High =OFF
( I have no real idea what that means unless it means you have to pull pson to low to get it to switch on.)

What do you mean by 'lamp connected'? Which lamp?

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

he means the wires from the power supply to the inverter board that lights the bulbs of the screen.
That board is still buried in your first pictures.


What I think we need is power to get to the Gate (yellow G) of the larger transistor

At this point, if it were my board, I would jump a ground line to that Gate and see what happens to the source (Yellow S) voltage wise and if nothing, I would then jump voltage to that pin

then IF the source activated, it should activate the smaller transistor and cause the number 3 pin to ground and if it does that then the relay should turn on

that is providing both transistors are good
and nothing goes POOF !!

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

he means the wires from the power supply to the inverter board that lights the bulbs of the screen.
That board is still buried in your first pictures.


What I think we need is power to get to the Gate (yellow G) of the larger transistor

At this point, if it were my board, I would jump a ground line to that Gate and see what happens to the source (Yellow S) voltage wise and if nothing, I would then jump voltage to that pin

then IF the source activated, it should activate the smaller transistor and cause the number 3 pin to ground and if it does that then the relay should turn on

that is providing both transistors are good
and nothing goes POOF !!

What is happening???

I jump a ground to Gate and now the Gate is 20v and Yellow S(source) is 5v.

And the pin 3 of 1305 is 0v.

When I power off and on the tv, the led light on the front panel is green and stay green. Before this, the led is green and after about 2 sec will turn red.