LG 26LC51 with bad capacitors..

[JonathanAnon]

Hi guys,

Have one of these on the table at the moment. It shows a blank screen and then comes on after about twenty minutes. voltages on the PSU checks out OK.
When I put the hairdryer on this bank of caps,



on the video board. it takes life after about a minute.

My question is: If I measure the voltage across these caps when I first turn on (and the screen is not working) and then heat up the caps with the hairdryer and measure the voltage again (when it is working), should I be able to identify the bad caps?

(nb. I know I should change them all anyway, I am just wondering should I be able to identify the faulty ones this way??)

[multimeter]

Re: LG 26LC51 with bad capacitors..

checking the voltage wont prove the ones that are faulty,you need an esr meter,and relavent datasheets

[JonathanAnon]

Re: LG 26LC51 with bad capacitors..

Yeah I tried it and it didnt make any difference... voltages the same when working and not working... I'm really trying to find a reliable way of identifying bad capacitors without having to shell out for an ESR meter.... cheapest I can get here in Ireland is 97 euro... And with the lack of money in this country at the moment

Gonna fire out all the caps with "crosses" on their tops and see how far that takes me.

[tom66]

Re: LG 26LC51 with bad capacitors..

Two "X" caps - G-Luxon. Known bad.

Left middle - Chemicon, good usually.

Others - Don't know maybe Samwha/Samyoung (known bad.)

Those caps look like for the audio amp? They may be unrelated to the problem and you could be heating up other parts.

[JonathanAnon]

Re: LG 26LC51 with bad capacitors..

I found a dry joint on an inductor on the power board, which I resoldered and seems to make it come on more often (though that could be just in my head).



that's the board with the section with the caps in yellow, I dont think it is part of the audio circuit.

[JonathanAnon]

Re: LG 26LC51 with bad capacitors..

Okay I swapped out those two Gluxon 35V caps and since this the TV has come every time...... but ONCE ... of about 100 switch ons, some from cold....

There is also physical damage to the A/V board.. you will notice the S video connector is slight pulled off the board and the coax port is damaged badly.. So I've priced up a new board.. Looks like it got one hell of a belt, either a drop or somebody reversed in to it with a truck..

[JonathanAnon]

Re: LG 26LC51 with bad capacitors..

After spending literally a couple of days on this ..... I've found out what the problem is...... NOTHING to do with the caps at all... After noticing that the picture seemed to "unfreeze" when the TV was physically moved, and reading John Preher's book, I stripped the TV down so that I could see the Flexible PCB cable that connects the driver board to the LCD screen.....

When I touch my insulated screwdriver head off the left most FPCB cable the TV comes back on every time.



The books say "there is no way to fix the FPCB cable". Is there anything at all I could do to hold the cable in place?

[tom66]

Re: LG 26LC51 with bad capacitors..

It is a common fault with Samsung, but I've never heard of LG's with the issue. You can insert a spacer or piece of foam in between the metal and the flex. It works ~90% of the time so give it a shot.

[JonathanAnon]

Re: LG 26LC51 with bad capacitors..

okay Tom, I'll give it a shot... There is some minor damage to the back left of the TV so I'd say it was dropped, so I'd say that probably caused it ... (rather that it being an issue with the model of TV)

[JonathanAnon]

Re: LG 26LC51 with bad capacitors..

oh man... I managed to crack the screen while doing it.. :-(

[tom66]

Re: LG 26LC51 with bad capacitors..

That sucks.... Well, at least you have some of the boards

[bugs_repairMan]

Re: LG 26LC51 with bad capacitors..

Does any one have the schematics or circuit diagram for the PSU of this TV?

The board its a part numb. EAX31845101/9 07.01.11 rev1.0
EAY33025101

Has can you see, some of the caps are boldgie a one of them almost explode!
The service Manual for this TV doesn't have all the capacitors description for replacement.

Can anyone help?

Thanks!

[nomoresonys]

Re: LG 26LC51 with bad capacitors..

Capacitor info is written on the side of it, uf, voltage etc. you want to get low esr caps not general purpose.

[nomoresonys]

Re: LG 26LC51 with bad capacitors..

Being 14 years old, I'd start with replacing the electrolytic capacitors on the powerboard, might be able to leave the 2 big filter caps and change the rest. Hard to tell which ones are good without the test meter/s or seeing obvious doming or something, they don't have to be domed to be bad. As always respect the HOT/DEADLY side of the powerboard, be careful what you touch.

[bugs_repairMan]

Re: LG 26LC51 with bad capacitors..

I leave the list of the caps I retrive from pcb and their location:
C502 - 33uF 63V
C506 - 100uF 50V
C507 - 47uF 63V
C203 - 470uF 35V
C123 - 1uF 63V
C220 - 470uF 16V
C204 - 3300 uF 10V
C215 - 2200uF 16V
C212 - 2200uF 25V
C216 - 470uF 16V
C208 - 470uF 35V
C207 - 1000uF 35V
C213 - 470uF 25V
C221 - 680uF 35V
C223 - 680uF 35V
C222 - 680uF 35V

can anyone validate this?

thanks!