element 32 inch lcd shuts off after 15 min

[freakaftr8]

hey all well I picked up this element 32 inch LCD TV kind of cheaply made. here's the deal if its on for about 15 minutes all the sudden you start to hear one of the output transformers start to squeal and if you let it go on long enough the TV will shut off and then come on in and shut off again and stay off sometimes it will come on really screwy picture but nonetheless it seems to be with in this area of the transformer no this transformer is stepping between the hot side in the cold side of the power supply.

What seems to happen is if I hit a rectifier diode next to the Transformer with freeze spray the squealing stops and the TV will stay on. So I replaced the diode. Still the same results.
have any of you dealt with this type of TV brand which doesn't seem to be made of Samsung or LG gutsat all its some really weird brand. I don't have any part numbers are model numbers of the moment since I'm at work but I was just thinking maybe somebody ran across this. Is there a possibility that the transformer itself is bad?.

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

by the way I check back light its not a backlight issueas everything powers down and I can't see anything behind the screen so as it shuts down I get a red light sometimes sometimes it's completely black there's no power at all and I can't turn it back on unless I it plug it back in right away

[budm]

Re: element 32 inch lcd shuts off after 15 min

I will wait for the model number and the pictures of the boards.

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

Tv model number elcfw327 and power supply model ay118l-4hf01

transformer in question is t1 and diode is d11. That I replaced. when I hit d 11 with free spray sound from the t1 goes away and tv will stay running

[budm]

Re: element 32 inch lcd shuts off after 15 min

Is this the one? http://assets.shopjimmy.com/media/ca...IMG_0774_1.JPG

Is it T1 or T1F? I cannot see D11 from the picture.

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

Yes that's the one.

[budm]

Re: element 32 inch lcd shuts off after 15 min

Where is this D11? Pictures of your board?

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

D11 is located right under T1 in the picture. I took some pics of my board but cant post them until tomorrow.

[hitandrun83]

Re: element 32 inch lcd shuts off after 15 min

sounds like some bad schotkey diodes. just had this in a emerson tv.

[budm]

Re: element 32 inch lcd shuts off after 15 min

I suspect bad start up cap C88, try heating up that cap or that area with hair dryer then plug it into the out let. You can also have bad D11, you need to take it off the board then use the meter in Diode mode, heat it up with hair dryer, write down the reading, then cool it down and take the reading, both directions to see what you are getting.
Also take the DC reading right at the two legs of that large 82uf 450V cap.

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

Good call. On d11 I already replaced it. And if I heat it up the tv goes dead right away. Its not d11 thou. This is odd.

[budm]

Re: element 32 inch lcd shuts off after 15 min

I would try new C88.

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

C88 replaced. Same effect. Oddly thou if I hit r69 with freeze the transformer stops sqealing. Works great. If I heat it up the ps dies immediately. Value is .39 ohm.

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

Replaced r89 c20 c79 c36. Still same issue. oddly enough everytime I hit any of these components with free spray as well the hissing would stop in the transformer don't really understand what's going on here. Why is it that any of these components I hit with freeze spray rhe hissing stops?the only thing I can possibly think of is when I freeze any of these components I slow down the ripple to the transformer. Now I'm just trying to figure out what would cause the AC ripple to go overboard. Also I'm possibly thinking that something may be under loading or overloading on the secondary side of the transformer on the output

[ohmmy]

Re: element 32 inch lcd shuts off after 15 min

Replace c38

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

Really I wad thinking that since it seems to be one of the components that stop the hissing t1. Have you run into this board before?

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

The only confusion I'm having is that I don't have a schematic for this board I can't obtain one unfortunately it's a cheap bored and it seems that seven or eight components that I cool down on the board seems to rectify the situation that's the weird thing about it I hit almost every single component that cures this problem it keeps coming back

[budm]

Re: element 32 inch lcd shuts off after 15 min

C38 and the other cap (I cannot read the number) next to black spot IC1 may be part of the filter caps for the SMPS IC. I cannot tell unless I can see the bottom side of the board, I would replace them as suggested by ohmmy.

[RJARRRPCGP]

Re: element 32 inch lcd shuts off after 15 min

sounds like some bad schotkey diodes. just had this in a emerson tv.

Emerson=Yuck!

[freakaftr8]

Re: element 32 inch lcd shuts off after 15 min

C38 replaced. rhere is a transistor to the bottom left of hs2 (heat sync) 2. That is q6. Immediate stop in hiss when I freeze it. Its a 2n2222 im looking for a replacement. I took a pic of the bottom of the power supply. Ill post asap