Bush IDLCD32TV16HD Dead

[gilly1984]

Just bought this off ebay, going to collect it at around 6ish, It has a IPOS 150 power supply.

Seen a few posts with this power supply, read them but it seems these are quite troublesome.

Picking it up tonight so will get some pics up.

[tom66]

Re: Bush IDLCD32TV16HD Dead

If it's a MEGMEET IPOS, probably some bloated CapXon on there...

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

Have to look tomorrow now, my lift was a little late so arranged to collect tomorrow.

Hopefully its a nice easy fix as you say Tom.

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

Ok, i have the tv now.

I have standby light, press the power button and the tv attempts to come on, hear the speakers hiss a little, but in a nice way.

No backlights come on, checked in a dark room.

All voltages are ok on the power board, i get the same readings as other posts on here.

Now, where do i start? And is it possible to test the cfls without killing myself?

[Th3_uN1Qu3]

Re: Bush IDLCD32TV16HD Dead

No backlights at all, not even a flash = inverter failure. Check the power rail going into the inverter (should be 24v on a set this size) and the mosfets on the inverter.

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

inverter is built onto the psu. I think I read that the inverter on the is supplied 240v

[tom66]

Re: Bush IDLCD32TV16HD Dead

Those two 4.7u 450V caps near the transformers are a -very- common failure.

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

Well, i USED to get a standby light,,,

I changed a 50v 22uf cap under the heatsink and now it wont work at all. It used to buzz a bit but now its silent?

I have put the original cap back in and still same problem.

What have i done to it? Is this a single layer board?

There is 330v across the big cap.

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

No matter where i probe, using chassis as ground i get either 140vdc or -140vdc?

[tom66]

Re: Bush IDLCD32TV16HD Dead

Primary is isolated, use -ve on primary cap as ground for primary.

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

All the voltages i used to have are gone, 5v 12v and 20v.

How can i have messed it up by changing one cap?

Cn you show me on pic what you mean tom, when you have time that is.

And a red led used to flash on the psu to say there was a fault but thats gone too.

[tom66]

Re: Bush IDLCD32TV16HD Dead

-ve = negative (shorthand)

So when probing anything on the mains primary side, do not use chassis ground, use primary ground (the negative lead on the big cap.)

Re problem checked for lifted pads cut tracks etc?

Your main problem is likely inverter as unique suggested.

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

if I put 84v through a 474 smd resistor should there be any voltage on the other side ? I may have broke it during the cap change.

[tom66]

Re: Bush IDLCD32TV16HD Dead

you don't put voltag through anything, voltage is always across something.

[retiredcaps]

Re: Bush IDLCD32TV16HD Dead

And is it possible to test the cfls without killing myself?

We never ask people to measure the AC voltage of the inverter transformers in the ccfl section. They can easily spike up to > 1000V AC during initial strike/ignition which will kill your multimeter in possibly spectacular fashion.

You can test ccfls "indirectly". The 2 seconds to black guide has an entire section on testing ccfls safely.

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

you don't put voltag through anything, voltage is always across something.

I wasnt going to put any voltage across it pal, just trying to figure out if i damaged the smd resistor, i have replaced it and still the same problem so i know its ok.

Just strange that i now have no power on the pins i did have power on before i replaced the 50v 22uf cap?

Thanks RC, i will have a look at that thread when i figure out what i have done wrong to lose all my voltages.

[tom66]

Re: Bush IDLCD32TV16HD Dead

You must have broke a connection somehow, check everything really carefully.

[gilly1984]

Re: Bush IDLCD32TV16HD Dead

Is this reading normal from the inverter tranny.

[tom66]

Re: Bush IDLCD32TV16HD Dead

You cannot measure the HV with a DMM. You have probably damaged the meter, but in the very least, measurement is not generally possible.

[retiredcaps]

Re: Bush IDLCD32TV16HD Dead

Is this reading normal from the inverter tranny.

One retiredcaps' bonus point for a picture of your multimeter.

You want to measure the resistance between the secondary pins. A diode test will report readings as voltage.