Polaroid 32in LCD FLU-3232 no power

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

No clicking. Fuse is fine (220v both sides). I've just checked the bridge rectifier and I'm getting (while live):

+: 120-160v
~: 220v
~: 0.6
-: 120-160v

Powered off now and waiting to discharge then I'll check the solder joint on that third pin.

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

Yeah ground is against the metal back panel.

Not sure what you mean - not a usual test point - can you retake the voltages putting the black lead on a ground screw - (In the corner of the panel) If the same try again using the GND pins on the 24v socket.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

The ground screws are screwed into a metal backplate. I tried the screws and also one of the GND pins I get the same result.

I've resoldered the bridge rectifier and it's no different. The second ~ pin is only registering around 1v, is that normal?

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

The ground screws are screwed into a metal backplate. I tried the screws and also one of the GND pins I get the same result.

I've resoldered the bridge rectifier and it's no different. The second ~ pin is only registering around 1v, is that normal?

Measuring relative to what?

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Measuring on 400v AC with red on the pin and block on the back plate, full results are top of this page

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

Fuse is fine (220v both sides). I've just checked the bridge rectifier and I'm getting (while live):

+: 120-160v
~: 220v
~: 0.6
-: 120-160v

.

Are you changing your meter to 600 VDC to measure across plus and minus?

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Was measuring with 400v on AC. I'm not sure what 600 VDc is

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

Ok - From the mains up as far as the middle two connectors on the rectifier the voltage is AC
after it is rectified it is DC so the outer pins are Volts DC so unless your meter is automatic you need to change it to measure in DC. - If it is auto ranging then as long as it is on DC you will be ok.

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

Normally we do not test the Bridge rectifier we just test across the BIG Cap
Meter set on vDC 600 or DC autoranging Black probe on negative leg and red probe on positive leg. If that is ok then the rectifier must be ok

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

I was on AC and getting that 220v on pin 2 and 1v on pin 3. I'm using the right setting there right? As for the other two pins I was using AC so I guess that's why I didn't get a negative reading

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

Another thought on the lower voltages is did you have the other boards all connected
as the power supply will usually not start up without signals from the main board.
You cannot unplug it and test on the pins you have to try and get the probe in the side or
down next to the wire.

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

I was on AC and getting that 220v on pin 2 and 1v on pin 3. I'm using the right setting there right? As for the other two pins I was using AC so I guess that's why I didn't get a negative reading

Yes that is correct - I would forget testing the Bridge Rectifier further - try the big cap as above.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Heh totally just shocked myself. Twice. Matter of time I guess.

The PSU is all connected although there's an annoying VGA type socket under the back plate and I've no way to tell if it connects up. I reseated all the cables but it's the same. Testing 4V DC I get 0.018 touching the back plate only, then 0.010 to 0.012 on any of the pins except 5VSB which gives .416 now.

The big capacitor with black on back plate and meter at 400V DC gives -161V on the side closest to the AC input, and +161V on the other side.

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

Just test straight across the cap. No grounding to case.

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

Without further shocking yourself you need to do the test as I asked
Perhaps you missed it as we were cross posting
"Meter set on vDC 600 or DC autoranging Black probe on negative leg and red probe on positive leg." It should be 230 x1.41 volts ie about 325vDC

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Ah sorry. 330V

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Note that I'm not sure which leg is which I can't see it on the side of the cap. I'm getting a positive reading by having black closest to the AC input. I don't know if it's possible that something could be flipping it all around (I'd assume not?) but I just thought I'd make it clear that I don't know which way around it was.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

(Deleted)

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

Ok that will do - Bridge and fuse and Big cap are ok - I cant help as I cant see much in the picture - sometimes there is a + on the board and the cap usually has a contrasting colour stripe down one side with - signs in it the leg on that side is negative.

We will move on to the next tests but can you get a bigger, brighter ,in focus picture of
your board.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

I'll see if I can get some better photos in a couple of hours. What do you need, that DC side of the PSU, or something else?