baird 42 flickering strobing wont start up

[wreksta]

hi all got this baird in tonight I know its a cheap set
problem is wont start up it flickers the light like a strobe and makes a clicking on the psu any thoughts wil get pics of psu asap

included a pic of mains and a video of what its doing

video here http://s2.photobucket.com/user/wreks...O0002.mp4.html

pics of psu

[vinceroger69]

Re: baird 42 flickering strobing wont start up

can you check the output voltages of the psu in another thread on a baird 42 inch it was a faulty invertor so if voltages are low maybe try to unplug the 24 volt invertor plug on psu ans see if volages are ok now.

[wreksta]

Re: baird 42 flickering strobing wont start up

mate can I have some more info on the above mate ie the values and how to test sorry for being a thicko

[notallbad]

Re: baird 42 flickering strobing wont start up

Do you have a DMM?

Measure voltages on the connector pins and note them here, remembering to number them and note the connector label.

Looks like the PS board connectors to the right of photo are from top to bottom

Main board
Audio (possibly) 4-pin (2 gnd and 2 might be 12,24 or 33v)
Inverter 10-pin (most likely 5 are gnd and 5 are 24v)

Refer to this thread for another Baird 42" (as suggested above):
https://www.badcaps.net/forum/showth...light=baird+42

[tom66]

Re: baird 42 flickering strobing wont start up

Also check voltage across the large 450V cap.

[wreksta]

Re: baird 42 flickering strobing wont start up

tom what should that 450 cap be

[tom66]

Re: baird 42 flickering strobing wont start up

Depends, what does it read? Around 380 to 400V steady I'd expect.

[wreksta]

Re: baird 42 flickering strobing wont start up

to test all these inverter connecter audio etc 450v large cap does it haveto be powered

[tom66]

Re: baird 42 flickering strobing wont start up

Yes, set should be powered and screen should be showing the fault.

[wreksta]

Re: baird 42 flickering strobing wont start up

mae my meter showing nothing can you explain in leymans terms what my my meter should be on please to test

this is my meter basic I know
http://www.petervis.com/electronics%...%20M-830B.html

[tom66]

Re: baird 42 flickering strobing wont start up

600V DC; from the off position, one click to the left.
Red probe in volt/ohm jack, black probe in COM.
Then touch red probe on one end of cap, black on other.
BE CAREFUL not to short the probes!!

[wreksta]

Re: baird 42 flickering strobing wont start up

tom I done as you said I get a 329 rising to 350 upon strobing and bk to 329 when not lighting leds if you get what I mean this is with all cables attached and powered

[tom66]

Re: baird 42 flickering strobing wont start up

Yeah, there's your problem. Low PFC voltage.
If you do not know how to repair a PSU I would advise a straight swap.
Before you swap it, I would try replacing these caps.

[notallbad]

Re: baird 42 flickering strobing wont start up

Try the same with inverter connector disconnected.

Wrecksta, video link not working

Tom, could an inverter fault be shutting down the tv before the main cap charges to full voltage?

[wreksta]

Re: baird 42 flickering strobing wont start up

tom not questioning you but can I ask why to replace the four smaller type capicitors rather than the large cap please explain mate

[tom66]

Re: baird 42 flickering strobing wont start up

Questions are good!

Because the smaller caps provide the Vcc supply for the controller chips; when they go bad, this symptom is common though it does not always occur.

When the big cap goes bad, it usually causes the voltage to rise to the correct level but the screen still flickers; OR, much more commonly, it causes the PFC circuit to fail & blow the mains fuse in a rather spectacular manner.

[wreksta]

Re: baird 42 flickering strobing wont start up

inverter in or out made no difference mate


okies tom so replacing them could fix the problem or help determine the true nature of the fault

so replace the
2x 100uf 35v 105c
1x 10uf 50v 105 c this is the orange one nrear the big cap

there is also another 100 uf 35v 105 c to the right of the big cap over the heatsink above the mosfet

[tom66]

Re: baird 42 flickering strobing wont start up

I'd replace those three and that smaller one too, then; I couldn't see that other one.

[wreksta]

Re: baird 42 flickering strobing wont start up

replacing them could fix the problem or help determine the true nature of the fault
okies will do that now if I have em

only uf's I have are all from a sky box they all right spec though will these do as going to sacrifice the box lol

[tom66]

Re: baird 42 flickering strobing wont start up

No, I would never re-use capacitors from an old product. Main issue is voltage forming -- the old capacitor can get used to being used at a certain voltage for a long time and may fail if an increased voltage is applied.

List the values you need and suitable replacements can be sourced. Also do not order crap caps, Panasonic FM/FR/FC are suitable, others may not be suitable.