Polaroid 32in LCD FLU-3232 no power

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

Definitely shorted then. Is that outside of circuit?

I have a few bridge rectifiers here, if your pic matches one of yours I'll throw it in the package.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Yeah that's tested outside of circuit. It looks like this http://i.imgur.com/3Wvzf.jpg

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

What should it do for those tests? Give a reading for all the pins and give the same but negative for swapped pins?

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

Dead on match for one I have here.

Test between 2 and 3. Should read the same as open circuit.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Pins 2 and 3 gives .008, as does touching nothing. Touching together (so open circuit) is now .003

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

Pins 2 and 3 gives .008, as does touching nothing. Touching together (so open circuit) is now .003

So, looks like your bridge is looking dead. That explains the blown fuse.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Awesome one step closer to fixing it! Do you want a bit of cash for the bridge so you're not short when you need to replace it?

Also, just for my reference for next time: what should the bridge read? And why can't I just use the resistance test on it? If it's supposed to be an open circuit shouldn't I be able to?

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

Awesome one step closer to fixing it! Do you want a bit of cash for the bridge so you're not short when you need to replace it?

Also, just for my reference for next time: what should the bridge read? And why can't I just use the resistance test on it? If it's supposed to be an open circuit shouldn't I be able to?

No problem. I bought them for 10p each, minimum order 5. Used one to fix a 42" LCD, fairly common failure.

The bridge should read O.L. on the AC pins, and from each ~ to + and - about 500 (350 - 800) in one way.

So e.g.:

Red/Black
~ to ~: "1"
~ to +: 500
+ to ~: "1"
~ to -: "1"
- to ~: 500
+ to -: "1"
- to +: "1"

Last two could read zero if there's a short further down the line.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

I'm a little confused, I only ever see 0L when I use the settings with ohms on. And is the reading 0L or 1? Also, I only ever say .009ish, would 500 be around .500? Or am I misreading?


I owe you and selldoor a beer

[selldoor]

Re: Polaroid 32in LCD FLU-3232 no power

Who said ? -Tom doesn't drink beer - doesn't like the stuff!

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Haha it's like you have an alert setup just for the word. More for you then I guess

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Oh one more thing I wanted to ask, this bridge was pasted and screwed to the heatsink. Is that something I need to make sure I do when I put it back?

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

I'm a little confused, I only ever see 0L when I use the settings with ohms on. And is the reading 0L or 1? Also, I only ever say .009ish, would 500 be around .500? Or am I misreading?


I owe you and selldoor a beer

I'll put a good diode 1N400x in the package for you to get to grips with your meter. A bridge rectifier is just four diodes connected together in a convenient package.

And no, I don't drink beer. (It's not a religious thing... I just don't like it.)

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

Oh one more thing I wanted to ask, this bridge was pasted and screwed to the heatsink. Is that something I need to make sure I do when I put it back?

Yeah you need some thermal paste let me check and see if I've got a small bit left. You just need a fingertip of the stuff.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Is that because it's heat sensitive? Should I be watching the temperature of the iron when I put it in?

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

No concern with soldering as long as you don't solder any pin for longer than 30 seconds.

The thermal paste is to ensure that the device doesn't overheat as it dissipates a fair bit of power.

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Thanks a lot for the parts. The bridge rectifier and fuse are now in place but I still don't have a responsive TV. I've tested the labelled connections at the end of the PSU on 40V DC and they're doing more than they were:

Reading just touching back plate: 0.1
STB: -0.00
5VSTB: 0.67
5V: -0.00
12V: 0.00
4x GND: 0.00
24V: -0.00.

What am I missing?

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

Ground on back panel?

Do you hear a slight ticking sound from the power supply?

[DoctorWedgeworth]

Re: Polaroid 32in LCD FLU-3232 no power

Yeah ground is against the metal back panel.

I didn't hear any ticking but the radio was on in he background, should I listen out?

[tom66]

Re: Polaroid 32in LCD FLU-3232 no power

Yeah ground is against the metal back panel.

I didn't hear any ticking but the radio was on in he background, should I listen out?

Try and listen carefully. Is the new fuse okay?