Philips 37PF7321/98 cannot turn on

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

take out one end of 5104 and recheck 1806 power plug pins
then check resistance at all 3 pins to each other on 7102

One end of 5104 taken out. Pin 1 to pin2 of 1306 plug is 12Mohm.

7102 transistor resistance
G to S is 0.5ohm
G to D is 0.5ohm
S to D is 0.3ohm

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

is 8105 cooked by the 7106

There is no 8105 or 7106.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

7102 goes POOF
STP6NK60Z

6105 3 pin diode
BZX394-C15

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

ok on the thin pink which means there ia a direct line from the capacitor by the main transformer all the way to the gate. only thing in the way is a diode that should be blocking that voltage. so that diode need to be check to see if it only allows resistance in one direction

so , at the transistor that I marked with the white A the trace that goes under that transistor is from the single pin side up to the 471 resistors right side ?
If that is the case, then we have to figure out where the top left pin of that transistor goes. the 253x white numbers cover the traces

FYI: At the diode at 6149- the top K pin goes to 5 volts at the 9065 jumper
and the jumper below that goes to the 0 resistor and also gets 5 volts and that feeds 5 volts to the 1 and 2 pins at the 1305 plug

There are 2 caps 2140 and 2508 by the main transformer. What cap and which diode?

471 resistor right side goes to the top left pin of transistor.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

parts that blew up are in the red circles
once removed the two resistors at the red arrows need to be checked

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

There are 2 caps 2140 and 2508 by the main transformer. What cap and which diode?

471 resistor right side goes to the top left pin of transistor.

never mind the caps
I found that info

FYI: From what I can see so far this morning- that 85 volts to the gate should probably be 11 volts, so grounding it to turn it on is incorrect

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

7102 goes POOF
STP6NK60Z

6105 3 pin diode
BZX394-C15

I should replace both?

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

parts that blew up are in the red circles
once removed the two resistors at the red arrows need to be checked

Have to remove the resistors to check? Or can check in-circuit?

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

Since they both are shot, you should remove them first or they may give you a false reading somewhere else

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

I should replace both?

7102 goes POOF
STP6NK60Z

6105 3 pin diode
BZX394-C15

6105 is 2 pin diode. Do you mean 7101 BC817-25W, 3 pin transistor?

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

This board is marked like shit and half of the crap in the datasheet diagram isn't even installed
Yeah, looks like the 7101

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

This board is marked like shit and half of the crap in the datasheet diagram isn't even installed
Yeah, looks like the 7101

Thanks Bammbammfran!

It will take a couple of days to get hold of the components.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

I figured that
If cheap enough, get a couple of each (My rule of thumb)

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

once we get power back then we can try to figure out why the 11v line is putting out 80+ volts

I originally thought that this standby only did the 5 volts
I wasn't expecting 12 volts since the power supply was doing that too !
New tracing attached

might be one of the 22k resistor or the 47ohm one creating an issue ?

I think that the transistor that I had marked with a white A is in line for some sort of overload protection since it doesn't appear to go anywhere else except to ground

I still haven't figured out what turns that 11 volts on and off to activate the 7531 transistor ??

[budm]

Re: Philips 37PF7321/98 cannot turn on

"once we get power back then we can try to figure out why the 11v line is putting out 80+ volts" is there a filter cap on the 11VDC line? It sounds like using the wrong ground ref point being used. There should be filter cap for that 11V if you truely have 80+V, the cap would have blown by now.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

"once we get power back then we can try to figure out why the 11v line is putting out 80+ volts" is there a filter cap on the 11VDC line? It sounds like using the wrong ground ref point being used. There should be filter cap for that 11V if you truely have 80+V, the cap would have blown by now.

he has been reading the other voltages correctly, so I am pretty sure this one is right
The 11 is actually 11.7 (or that is what it should be)
there seems to be a polyester 100pf 5% 1kv in line on the 12 volt line and just out of the transformer , so that should have held up ? Not sure if grounding the 12 volt side could have caused that to get damaged and start pumping higher voltage ?
and a 22uf and 10uf 50v radial electrolytic from 12 to ground further down the circuit

what is odd, is that this 11.7 feeds a transistor gate and it had no voltage till it was grounded, then it jumped to 20 volts and cooked the transistor.
after the transistor was taken out of the circuit ,it shows 80+ ??

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

standby board circuitry

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

I figured that
If cheap enough, get a couple of each (My rule of thumb)

Is BC817-25W,115 the same as BC817-25W? For BC817-25W,115 the minimum order is 20pcs whereas BC817-25W it is 250pcs!

The package type is UMT vs SOT-323.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

the npx version is also a sot-323


You may want to grab another 7531 since you grounded that one to test it

did you see I posted part of the wiring schematic
I got it this morning
Wish I had it a week ago !!

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

the npx version is also a sot-323


You may want to grab another 7531 since you grounded that one to test it

did you see I posted part of the wiring schematic
I got it this morning
Wish I had it a week ago !!

It is in the service manual, I thought you already have it?