Philips 37PF7321/98 cannot turn on

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

I am trying to get my head around it Its quite a complicated circuit (for me) perhaps
need to wait for budm or bammbammfran to come back at those voltages it would be unwise to guess!

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

It seemed like you HAD power since your front led of the monitor were lighting
but 63volts on your main caps says otherwise
6307 is the main bridge rectifier and should have full power
check the two end pins against each other for DC on the 6307 bridge rectifier
the 1350 relay looks like power is going through it if it has power to pins 2 and 3
1 and 4 are probably the switching pins (what plugs into the small jack that is next to it ?)

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

If I am looking at things correctly ??
It looks like this power board will not show power as a stand-alone board
looks like 6306 creates a bit of power and sends it to the main board through the 1315 fuse and the 1306 black connector and then the main board sends it back to the relay via the 1305 white connector and then the relay sends power from pin 3 to pin 2 then to the 2nd pin in on the main bridge rectifier at 6307 (since it isn't marked , lets let pin 1 of the bridge rectifier be the one that is closest to the boards edge)
so if those two wires are connected, you should have 240ac at the bridge rectifier center pins

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

That is partly what I thought though I think the Main/standby/audio board
may just send 5 volts back to the relay ( as it it only rated for 5v?)
Then when the relay works it switches on the rest of the 240v circuit which charges up the main caps and fires up the Inverter?

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

It seemed like you HAD power since your front led of the monitor were lighting
but 63volts on your main caps says otherwise
6307 is the main bridge rectifier and should have full power
check the two end pins against each other for DC on the 6307 bridge rectifier
the 1350 relay looks like power is going through it if it has power to pins 2 and 3
1 and 4 are probably the switching pins (what plugs into the small jack that is next to it ?)

The black jack 1306 has 342vDC and goes to the standby/audio board.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

342 volts !!!!
That doesn't sound right ??did you check it using just the 2 pins in that jack (pos to one and neg of tester to the other)
what is the numbers on the small black 4 pin chip at 6306

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

For 6307,the AC and DC voltages are almost zero. Shouldn't it have 240vAC as the pin2 and pin3 of relay 1350 has 240vAC.

I don't know whether this help or not. When I plug in all connectors to the power board, on the 6307 rectifier, pin 2 and 3 has 11vAC and pin 1 and 4 has 61vDC and decreasing slowly.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

I have a feeling you may not be using the tester correctly or it needs batteries

either way we need to start at that 1306 connectors
if you had 342 volts there, it would have blown that small cap clear out of the board (I doubt that is a 400v cap!) and it probably would have blown that 250v fuse

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

342 volts !!!!
That doesn't sound right ??did you check it using just the 2 pins in that jack (pos to one and neg of tester to the other)
what is the numbers on the small black 4 pin chip at 6306

With all connectors plug into the power board, the pins at 1306 has 338vDC. The DC pins at 6306 also has 338vDC. Yes, pos to one leg and neg of tester to the other leg.

6306
DF06 -> 1st line on IC
635A -> 2nd line on IC

[budm]

Re: Philips 37PF7321/98 cannot turn on

Please tell us what point on the board you are using for the Ground ref point when you are making voltage measurement in the primary side and in the secondary side of the circuits?

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

I have a feeling you may not be using the tester correctly or it needs batteries

either way we need to start at that 1306 connectors
if you had 342 volts there, it would have blown that small cap clear out of the board (I doubt that is a 400v cap!) and it probably would have blown that 250v fuse

I double check, it is 338vDC at 1306 connector. I hope I did not use the tester wrong and wasted your time. I attached the tester. It is a new tester. How should I test that it is working correctly?

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

Please tell us what point on the board you are using for the Ground ref point when you are making voltage measurement in the primary side and in the secondary side of the circuits?

I am very new with this stuff.

For DC, I use the chassis as Ground ref and touch the pin that I want to measure. For AC, I touch pos probe on one pin and neg probe to the other pin.

I hope I am not wasting everybody's time.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

I am not familiar with that meter. Mine are not auto-ranging
Check your house receptacle to check ac
and a standard battery or car battery to check the DC

hey Budm, does that sound right to you that the small DF06 bridge rectifier is pumping out 340 volts dc and that the audio/standby board is changing it to 5 volts dc to turn on the power supply relay ?
Can't find enough in DF06 datasheet
600v rated, 1.1 v forward voltage max and 1.5 amp

[budm]

Re: Philips 37PF7321/98 cannot turn on

"For DC, I use the chassis as Ground ref and touch the pin that I want to measure"
Well, when he is making that DC reading in the primary side of the circuit he should never use the chassis as the ground ref point, that is why his readings in the primary side are invalid, he need to use the negative leg of the main filter cap as the ground ref when making DC voltage reading on the primary side, the secondary side he can use the chassis ground.
I work on this model before so I will have to look at the SCH again to give him the test points.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

OK
I just looked at that fuzzy picture of the audio/standby board and it looks like it has an AC section and a transformer to DC section, so 340 +- may be correct
SO
Hook the power supply to the audio/standby board with those two wires and check the two pins on the relay to see if it is getting 5 volts of DC
The relay should click on
Check with tester pin 1 to pin 3

If that is ok
check for power again on the main large caps by putting the tester pins on the two pins on one of the large capacitors

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

I am getting 0v on the relay at pin 1 and 4. As soon as I plug the power supply board to 240v, there is a click sound and pin 2 and 3 has 240vAC. This relay should be normally open, right? So pin 2 and 3 should be open, right?

Is this relay bad?

When I touch neg probe of tester to neg leg of Big Cap and the pos probe to pin 1 of 1306, there is 0.2vDC. Same for pin 4.

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

"For DC, I use the chassis as Ground ref and touch the pin that I want to measure"
Well, when he is making that DC reading in the primary side of the circuit he should never use the chassis as the ground ref point, that is why his readings in the primary side are invalid, he need to use the negative leg of the main filter cap as the ground ref when making DC voltage reading on the primary side, the secondary side he can use the chassis ground.
I work on this model before so I will have to look at the SCH again to give him the test points.

I put the neg probe on the neg leg of one of the 2 Big Cap, the reading at 1306 is 140vDC on one pin and -80vDC on the other. Is these measurement correct?

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

I believe it should be open and that when 5 volts gets sent to pins 1 and 4 (one would be + and one would be -) then 2 and 3 would connect.
If it for some reason connected as soon as you plug power in
and you are getting 240 at the pins. then the power should be going through it and you should be getting 340 at the large bridge rectifier and at your large caps.

since we are checking 240 and there is no ground on the main power side of the board to work with: Use your black probe of your tester on the main fuse, then probe pin 3 of the relay, then check to see if that same voltage is on pin 2 of the relay and on pin 2 of the large bridge rectifier
then unplug the white plug by the relay and check these again (leave the black plug in)


TIME FOR SOME SHUTEYE !!

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

I believe it should be open and that when 5 volts gets sent to pins 1 and 4 (one would be + and one would be -) then 2 and 3 would connect.
If it for some reason connected as soon as you plug power in
and you are getting 240 at the pins. then the power should be going through it and you should be getting 340 at the large bridge rectifier and at your large caps.

since we are checking 240 and there is no ground on the main power side of the board to work with: Use your black probe of your tester on the main fuse, then probe pin 3 of the relay, then check to see if that same voltage is on pin 2 of the relay and on pin 2 of the large bridge rectifier
then unplug the white plug by the relay and check these again (leave the black plug in)

Goodnite bammbammfran.

When I touch neg probe of tester to fuse 1314 and pos probe to pin 3 of relay 1350, there is 240vAC. If I touch pos to pin 2 of relay, there is 0.8vAC.

Neg probe to fuse and pos probe to pin 2 of large bridge rectifier 6307, I get 1.25vAC.

With the white connector unplug, pin 2 and 3 of the relay have the same reading as above. Pin 2 at large bridge rectifier 6307 has 0.8vAC. But there is no click sound.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

is it morning already !!

Looks like the relay might not turning on
and it is not letting the voltage go to the large bridge rectifier
before , you said it had power at both pins, but you were probably probing these two pins incorrectly (possibly at the same time ?)

since it does click, the voltage should be getting to it from the other board to 1 and 4 even though you did not get a reading the first time. (Did you unplug the small white plug while the power plug was in or did you unplug it then plug the power in)
IF you unplugged it first: try to unplug it while the power is plugged in to see if it clicks and then plug it back in while the power plug is in to see if it clicks again.
If it does not click on and off, you can try an external 5 volt source to the pins 1 and 4 of the relay(old phone adapters are around that or 4 AA batteries end for end with two wires)

FYI: IF you notice on that power board on the top side there are lines with slashes across them on the top and on the bottom there are similar in the areas that are not green.
these are separations between high voltage and low voltage areas.
SO, that makes the relay on a low voltage side.

So, if a board is loose, when you check for DC on low voltage sides, you need to use a low voltage side ground (easiest to do is usually a negative/ground pin of a capacitor)
and on high voltage sides and high voltage cap.
If the board is mounted on a metal frame, you can usually do low voltage using a frame as ground which is why they have the screw areas also marked off as low voltage side, BUT, in this case , I do not see grounding pads on the screws to allow this ?