Help With Bad Cap ID on LG M208WA

[softicicle]

Hello everybody,this is my first post.I really need your help identifying what i beleive is a bad cap,and a chip that i dont know the name of,maybe a resistor ?
Heres are 2 pics showing the caps,the ones in black.

https://www.badcaps.net/forum/attach...id=10769&stc=1
https://www.badcaps.net/forum/attach...id=10770&stc=1

As you can see,er if ive posted the images properly,theyre numbered 002A at the top,and below DB712 .Can anyone identify these and tell me what sort of caps they are,also a part number would be very helpfull.

And heres the chip i would like help in identifying,i dont know what its called

https://www.badcaps.net/forum/attach...id=10771&stc=1
https://www.badcaps.net/forum/attach...id=10772&stc=1

The chip was slightly rippled on top and faded,the only lettering i can see is :
Top line - first letter is maybe an F , then what looks like AH12 .Underneath on the second line all i can see are the numbers 334 .
As you may have realised im a bit of a noob at this.
Im ok when im not picking the soldering iron up like a pen . Thanks

[Wizard]

Re: Help With Bad Cap ID on LG M208WA

1. State the problem with this TV in first place, we're lost.

2. This 8 pin IC is self contained switching buck regulator to this grey object is a inductor (coil with ferrite core) where pair of capacitors ahead of it is output capacitor filters. These caps should be good as it looks like UCC with brown jacket.
There is a black heatsink with 3 terminal voltage regulator. Not part of this group. It's for different section to supply with this regulated voltage via this linear regulator (this is reason for heatsink, that's normal for some heat produced.).

3. This second picture area is audio ampifier using PWM amp IC with that pair of grey inductors and few caps around it for filtering and other two is for isolating electrically; breaks the circuit so no current can flow (think this: Amp can float bit higher but speaker's other side is at ground. Cap is placed in between amp and speaker so nothing can flow to damage the speaker with unbalanced voltage float). but "uses" the cap as to transfer ampified audio energy to the speaker.

4. Third photo is a medium current diode. What is on there other side in that area of this diode? Is that where first photo is located in that area where inductor coil is? that's to block reverse flow of voltage on the output of the coil to the caps.

Cheers, Wizard

[PlainBill]

Re: Help With Bad Cap ID on LG M208WA

When trying to identify the type of component, look at the label on the pc board next to it. The first letter will tell you what type of component it is. A few of them are

C - Capacitor

D - Diode

IC - Integrated circuit

L - Inductor

Q - Transistor

R - Resistor

T - Transformer

PlainBill

[softicicle]

Re: Help With Bad Cap ID on LG M208WA

Thanks for the replies.The tv has sound but no picture.Heres some pics of the power board
https://www.badcaps.net/forum/attach...id=10775&stc=1
https://www.badcaps.net/forum/attach...id=10776&stc=1
The power board is made by yuyang telecom and serial is :
YP1504PG 6871TPT318G
https://www.badcaps.net/forum/attach...id=10777&stc=1
Theres nothing obvious like bulging caps or anything,i havnt checked voltage or anything else.
Pics and serial of the video board :
https://www.badcaps.net/forum/attach...id=10778&stc=1
https://www.badcaps.net/forum/attach...id=10779&stc=1
https://www.badcaps.net/forum/attach...id=10780&stc=1
EAX34000306(0) CHASSIS:LP69G 070130 Y.H.C M8W

And heres a closer pic of the 002A DB712 (has L1104 on the pcb next to it,is it an inductor plainbill ? ) ,it has a brown spot in the middle which made me think that it was the problem.
https://www.badcaps.net/forum/attach...id=10781&stc=1
Directly next to the solder joints L1104 is the D1101 i also think could be faulty.
https://www.badcaps.net/forum/attach...id=10782&stc=1

Thanks again for your help , its much appreciated .

[Wizard]

Re: Help With Bad Cap ID on LG M208WA

Now that more clear with the problem. Put it back together so you can run it again. Now get room really dark, and with a flashlight, make sure you have light (white or snowy picture even turn menu on with remote), flashlight on, bring it really close to the LCD surface and move around till you can see anything. If you can see hint of snow, picture or menu. That means backlight part of the PSU is the problem.

Cheers, Wizard

[softicicle]

Re: Help With Bad Cap ID on LG M208WA

I put everything back together and im getting a picture now,vertical coloured (colored) stripes,backlight is nice and bright.Ive repaired a few laptops before and id say it was a bad inverter,i dont know why it wouldnt even show anything before,maybe a bad connection or something.Ive turned it on from hot and cold,does this now rule out the power board and backlight .

[ratdude747]

Re: Help With Bad Cap ID on LG M208WA

maybe you had a cold joint in the inverter.

[softicicle]

Re: Help With Bad Cap ID on LG M208WA

Yes maybe,but that still leaves me with a problem.Theres vertical coloured lines on the screen. Can anyone identify the parts i mentioned previously ? ,they are the only things i see that are possibly bad.Id like to order the parts and try it. Cheers

[softicicle]

Re: Help With Bad Cap ID on LG M208WA

Ive reread what you said wizard and done a bit more research.To be honest most of what i read the first time went right over the top of my head.Sorry just laziness on my part. So , i need an inductor (coil with ferrite core),and a medium current diode.Am iright in saying that the 002A on the inductor means 2 amp ? and can anyone tell me what the DB712 means .Ive done a search on farnell and digikey and found nothing.thanks

[PlainBill]

Re: Help With Bad Cap ID on LG M208WA

Ive reread what you said wizard and done a bit more research.To be honest most of what i read the first time went right over the top of my head.Sorry just laziness on my part. So , i need an inductor (coil with ferrite core),and a medium current diode.Am iright in saying that the 002A on the inductor means 2 amp ? and can anyone tell me what the DB712 means .Ive done a search on farnell and digikey and found nothing.thanks

Probably not. The colored stripes indicate a problem with either the LCD panel or the main board.

1. The connector P1101 (directly above D1101) is the output connector for the power supply. Measure the voltages from the pins labeled GND to the pins labeled 5V and 15V.

2. Double check the cables going to the LCD panel, make sure they are seated properly.

PlainBill

[softicicle]

Re: Help With Bad Cap ID on LG M208WA

Ok , ive measured the voltages.I only have a analogue multimeter though,i`l borrow a digital one if it has to be very accurate. The 5V voltages measure very very slightly over 5V , and the 15V measure very slightly under 15V .

[tmwalsh]

Re: Help With Bad Cap ID on LG M208WA

Softicile, the inverter board does basically one thing: take low voltage and convert it to high voltage used to power the cold cathode fluorescent tubes along the sides/bottom-top of the screen. The light they produce makes the image visible.
If the screen is lit up, the inverter is working.

Generally if you get lines, the 'control' board that generates the row+column address, and the R/G/B signal to send to that address is wonky.[disfunctional] It is possible that the drive chips/transistors are shorted, and send a signal all the time for specific rows or columns. Most times when that board goes away, unless you can find bad components, it is time for a new unit.
When you say you have a picture with colored stripes, is that a broadcast picture? Are the stripes one pixel wide/tall or are they a 'swath' of multiple pixels? I would check the ribbon cables on the LCD and the control board to make sure they are seated properly. If not, they can have ground problems or send power to the wrong place at the wrong time.
tom

[PlainBill]

Re: Help With Bad Cap ID on LG M208WA

Ok , ive measured the voltages.I only have a analogue multimeter though,i`l borrow a digital one if it has to be very accurate. The 5V voltages measure very very slightly over 5V , and the 15V measure very slightly under 15V .

The normal tolerance on these voltages is 10%, often the 5V is slightly high (5.1V). The readings are nominal.

Recheck all cables then post pictures showing the problem. 1 picture = 1000 words.

PlainBill

[softicicle]

Re: Help With Bad Cap ID on LG M208WA

Ive rechecked all the cables and taken some more pics.1st 2 pics are from cold and 3rd pic is after i left it for 5 minutes,switched off then straight back on again.

https://www.badcaps.net/forum/attach...id=10824&stc=1
https://www.badcaps.net/forum/attach...id=10825&stc=1
https://www.badcaps.net/forum/attach...id=10826&stc=1

thanks again guys,i appreciate all your help.

[PlainBill]

Re: Help With Bad Cap ID on LG M208WA

Interesting. What happens if you change the channel, hit 'Menu', etc? Does the display change, or is it frozen?

PlainBill

[Wizard]

Re: Help With Bad Cap ID on LG M208WA

Check your LVDS cable is it wires or ribbon style? These are very delicate, always unplug at the plugs only. Never on the ribbon or wires themselves.

Did you press around on the LCD and T-CON board (small board between LCD and the mainboard? Even flexing the mainboard? Even flexing the LVDS cable/ribbon?

I didn't mean put tv BACK together with cover on. I meant put back together so you can measure and wiggle stuff with back off.

Cheers, Wizard

[softicicle]

Re: Help With Bad Cap ID on LG M208WA

hi,sorry for late reply. wizard,the cable is ribbon style,i have been carefull with it.i took the cable off and checked for continuity,it tested ok.I havnt flexed any boards or bent any other cables.I didnt put the whole thing back together with screws i just placed everything loosely into the back cover to test,it was easiest way.Plainbill,il post some more pics and do more tests tomorrow.

[Wizard]

Re: Help With Bad Cap ID on LG M208WA

Cool then. Awaiting your results.

Cheers, Wizard

[pagy snv]

Re: Help With Bad Cap ID on LG M208WA

Hello everybody,i have the same power board and some SMDs are deffect.Look on picture attached.Can somebody write me the names of theese parts?
Thank you.

[softicicle]

Re: Help With Bad Cap ID on LG M208WA

wow,i can`t beleive i started this thread 2 years ago ! A lot has happened in 2 years,sorry to everyone who tried to help me.Ive still got a service guide for this tv,i can email it to you.