HP W1907V Squealing

[selldoor]

Re: HP W1907V Squealing

I agree its probably bulb/s or wiring but its worth having a look. Dont recognise cap brand and they look ok but if the primary voltage to the transformer is dirty it wont help.

Have you tried turning down the brightness - may reduce the sound and still be bearable to watch.

[spleenharvester]

Re: HP W1907V Squealing

No change when adjusting brightness. The hiss gets quite loud from 70~90, though.

[spleenharvester]

Re: HP W1907V Squealing

I do have a 1 CCFL 15" laptop display here, one connector with white and pink wires, it's an LTN150 something or other. Would I be able to test it on the inverter in place of the other CCFLs one by one?

[selldoor]

Re: HP W1907V Squealing

Yes that is a good test ( may or may not prove anything as the difference in tube length may detract from the result) It may show up which bulb/wiring is bad

[spleenharvester]

Re: HP W1907V Squealing

I shall give it a shot when I get back from town.

Also, managed to flip the LCD round and did a test recommended earlier:

Top CCFL in bottom sockets - hisses
Top CCFL in top sockets - hisses
Bottom CCFL in bottom sockets - hisses
Bottom CCFL in top sockets - hisses

[selldoor]

Re: HP W1907V Squealing

I shall give it a shot when I get back from town.

Also, managed to flip the LCD round and did a test recommended earlier:

Top CCFL in bottom sockets - hisses
Top CCFL in top sockets - hisses
Bottom CCFL in bottom sockets - hisses
Bottom CCFL in top sockets - hisses

Hiss hiss - BOO!

[spleenharvester]

Re: HP W1907V Squealing

Hehehe! Just reassembled it, oddly enough the noise isn't so bad now - it's still there, and it's still a pain in the ass, but it's not as loud.

More accurate description - with a good listen, I wouldn't say it's a hiss now, it's a really high pitched whine with a quiet rattling sound to it (kind of like a hard drive?).

Reading around, some places say it could be the coils vibrating, and to put something on to stop it vibrating. Should I try this? Is it even possible with this shaped component?

EDIT: Also, wiggling the CCFL/power cable doesn't change the frequency anymore, so maybe I reseated something.

[Rtech]

Re: HP W1907V Squealing

Maybe,Still try the other backlight you had,and see if that makes a difference.

[spleenharvester]

Re: HP W1907V Squealing

Just tried the other CCFL, no difference unfortunately.

[spleenharvester]

Re: HP W1907V Squealing

Right, got the thing open on a test bench, big rectangular inductor chip is most definitely creating the noise here. Some slight whine coming from the coil next to the fuse but it's not really noticeable from afar.

Pressing lightly on the chip muffles the sound a bit. So I'm guessing I have to either find some way to silence it, or replace the power board?

Yet another realization! When it's turned on without CCFLs plugged in it makes the noise and then goes silent. The same thing it does with only 1 CCFL plugged in. I think we can be pretty sure it's the PSU board now.

[spleenharvester]

Re: HP W1907V Squealing

http://www.ebay.co.uk/itm/LCD-Monito...-/120873710445 that look okay to you guys? No sore thumbs sticking out? Just wanna make sure it's not some cheaply made replica.

[Rtech]

Re: HP W1907V Squealing

http://www.ebay.co.uk/itm/LCD-Monito...-/120873710445 that look okay to you guys? No sore thumbs sticking out? Just wanna make sure it's not some cheaply made replica.

If you are located in the UK, then dont buy this yet ?????//

[Th3_uN1Qu3]

Re: HP W1907V Squealing

"That large rectangular thing" - is the inverter transformer. And yes, it may very well be responsible for the noise. Unfortunately yours is covered with something - if the windings were exposed, you could have tried brushing on a coat of clear lacquer and letting it dry, in most cases it gets rid of the sound, or at the very least, attenuates it greatly.

You know you can buy just the transformer? Look for any codes on it, and it's likely to be available on ebay and other online stores like lcdparts.net .

[spleenharvester]

Re: HP W1907V Squealing

There's a small gap round the sides, reckon I could slip some in?

I'd prefer not to replace the individual transformer because my soldering skills are tragic to say the least :p caps is about the best I can do!

@Rtech - they post to UK.

EDIT: Furthermore this link shows one with the top flipped off. Is there any way I can pry it or is it glued on somehow? http://www.justanswer.com/uploads/Pl...erter-Xfmr.jpg

Also, is there any way I could just submerge the thing in lacquer, or would this damage it? It's honestly not too loud now, it's just at that pitch that makes me nauseous.

[budm]

Re: HP W1907V Squealing

Is the noise coming from one transformer or from both?
http://s807.photobucket.com/albums/y...cpZZ1QQtppZZ36

[spleenharvester]

Re: HP W1907V Squealing

Just the one matey, the rectangular inverter transformer. There's a small amount coming from the smaller transformer but not loud enough to really hear in front of the monitor.

If I do find a way to lacquer the inverter transformer I'll probably do that one too.

EDIT: Very odd, you seem to have a different revision of W1907. Mine only has one transformer and the audio is on the logic board instead.

[Rtech]

Re: HP W1907V Squealing

One is normal in the UK,Varnish is the thing to use,if you want to try flooding it with that,it may work, otherwise your choices are:-
Live with it as it is, new transformer or new Board,I think we can get cheaper and quicker than China, if you want to go down that road ?/

[selldoor]

Re: HP W1907V Squealing

EDIT: Furthermore this link shows one with the top flipped off. Is there any way I can pry it or is it glued on somehow? http://www.justanswer.com/uploads/Pl...erter-Xfmr.jpg

.

The top is not flipped off yours is like the middle top one in the picture.
Top picture is the underside - the top does not come off.

You would have to unsolder the eight pins and resolder after varnishing.
Hardest bit is getting it unsoldered you have to be firm but gentle easing the whole thing up a bit at a time.

[spleenharvester]

Re: HP W1907V Squealing

Damn :/ I can't find any boards that are in the UK though :p

I have some of this stuff, guessing it's the wrong stuff but it's worth a shot - would it work? http://www.amazon.co.uk/HYCOTE-SPRAY.../dp/B005C9B3BE

[selldoor]

Re: HP W1907V Squealing

This is more what you need - if you want to take that route.

http://www.ebay.co.uk/itm/TRANSFORME...item19d4beb879