HP LP3065 Not working (Flicker, noise, patterns)

[selldoor]

Re: HP LP3065 Not working (Flicker, noise, patterns)

Time has come for a picture of it - it probably has at least one fuse and a few things labelled FL
which on some boards means fusible links - have you tested any of those.
Are there 4 cables that go to the panel? have you disconnected/reconnected those?

[antome]

Re: HP LP3065 Not working (Flicker, noise, patterns)

Ok here are 2 pictures of it. It does have 4 cables going to the panel and I have tried to disconnect/connect those before.

I did find one fuse on it (F1 - 63V - 2A) that you can see on picture 2 near the bottom close to the connector. I also found a lot of FL's (like ~20 of them). I have not tested any of those. I don't know how I would test them, please explain. I guess I should be able to measure the F1 just by measuring straight across it with a low resistance setting? But can I do so safely without first desolder it?

[selldoor]

Re: HP LP3065 Not working (Flicker, noise, patterns)

Hi - You can test the fuse on the board Power OFF Meter on ohms 200
one probe on each side of fuse - should be the same result as touching the probes together. - Same or very close with the FLs

Also if it can be switched on at this point check the volatage on each side of the fuse - looks like it should be 18v so meter on vdc20 black probe on a ground screw put red probe on each side of fuse.

To take the flat cable out you need to raise that brown bar - very carefully
both ends together (They get quite brittle) the ribbon should then slide out.
The ribbon can be cleaned by rubbing across it with an eraser or a qtip with isopropyl alcohol.

[antome]

Re: HP LP3065 Not working (Flicker, noise, patterns)

OK, I measured all the FL's and the fuse and they seem ok. I also checked the voltage before and after the fuse and it was 17.8 V o both sides.
While having the monitor turned on when I checked the voltage on the fuse I noticed that the high pitch noise is actually coming from the T-con board. It is however not a constant noise, it changes depending on the "pattern"/flicker that is on the screen at the moment.
Maybe that can indicate something?

[antome]

Re: HP LP3065 Not working (Flicker, noise, patterns)

... and I tried to clean the flat cables like you said but with no result.

[selldoor]

Re: HP LP3065 Not working (Flicker, noise, patterns)

Ok not much on the board that can make a noise - is the the components like L1?
Another thankless task on top of the FLs would be to do the same test on all the 000 rated resistors - (example R236 near connector cnr2) they are sometimes used as jumpers or even fuses. On here they dont seem to be jumping any other traces so not sure why they are there.
Same test as before = power off- ohms test for continuity.

[antome]

Re: HP LP3065 Not working (Flicker, noise, patterns)

All 000 rated resistors measure as close to 0 ohm as my meter will go, so they are ok. I tried to listen while powering it on again but I can not tell for sure if the noise is coming from the inductors (L1, L2) or not, but it seems likely. I also hear like a small "ticking" noise from the same area.

[Davi.p]

Re: HP LP3065 Not working (Flicker, noise, patterns)

Hi antome, it seem a bit to me like a blind-to-deaf discussion, i'm not an expert but it is since the first post that i've understood that neither lamps nor inverter is the problem, in very stranges situation you can give the guilt to psu of another part malfunction but in the end always the T-con seem to be the faulty part, my suggestion is: set all parts so you have the component side of tcon facing to you and you can switch all on, take an hairdryer and/or a freezer spray and apply them one by one to each IC of tcon, if you find that one makes difference try to find that on internet and replace it. And one request to all forum members: do not forget always question marks, it is difficult for some like me to understand another language and also errors. Bye.

[antome]

Re: HP LP3065 Not working (Flicker, noise, patterns)

Hi, Thank you for your information.. I was starting to feel like it was a lost case by now.. However I did some more test like you suggested with a heat gun on the components of the T-con board.. When I did this on the big chip I did notice some changes on the screen.. I did even at some point get it to show parts my desktop image for a while and pressing on the chip itself also had an effect on the image. So it appears as if the 'LG.PHILIPS LCD KE5M3U1995' is defective in some way. I have looked at all the solder joints and they appear to be ok, but it is hard to tell just by looking at them.

I did some googling around and those chips appears to be hard to get ahold of for a reasonable price. And to be honest I am not all that confident that I will manage to replace it without damaging something.. I have done some fine pitch QFP soldering before, but not like this :P
Do you have any more suggestions regarding this?

[Davi.p]

Re: HP LP3065 Not working (Flicker, noise, patterns)

I'm trying to learn some new techniques in soldering, like the 'drag' type seen on youtube, for now it is only a failure, the only method that is passable is for very little legs chip: put some flux paste, fix in place chip, solder 2 opposites pins so it stay in place, apply solder to all pins so them will probably join togheter, after take solder wick and slowly suck the excess making attention to not dry too much, after it control VERY well with magnifing glass if there are joined pins or pins without solder. For the chip to find it, you can try ebay, or sites full of component distrib. companies, like hkinventory.com, is not simple to find those with 1$ minimum order. Bye.

[Davi.p]

Re: HP LP3065 Not working (Flicker, noise, patterns)

i don't know how many inches your monitor is, but if is very big you can try to search for a replacement tcon on sites like shopjimmy.com. Apart from this, if you mean for big chip a very big one it is better to heat more precisely before replace it with a very hard job and cost, try to heat each chip/transistor of tcon with the stick solder iron. Before this with the finger feel if one chip is suspectable hot. A picture of tcon can maybe of interest.

[HPLP3065]

Re: HP LP3065 Not working (Flicker, noise, patterns)

This may helps

http://item.taobao.com/item.htm?spm=...id=15856610547