Seiki se421tt

[heavymachines]

Hi i have this 42 inch led tv, i replaced the power board and the new one is doing same thing as old, it will run for few hours then shut off. Let it cool down and it will work again for few hours, I noticed the transformer gets very hot assuming this is the reason it shuts off display and power led will remain blue.
Any help will be greatly appreciated, when i got this tv in here base was broke and cord was cut, i fixed the base and eliminated the cord to a 3 prong socket out of a junk power supply for a computer, cut a hole in the plastic casing to mount the new socket and looks very nice... any ideas what could be causeing the transformer to get too hot?

[gilly1984]

Re: Seiki se421tt

Is there a fan anywhere? If not try running a 12v pc fan over the hot are and see if it goes off. Could do some more handy work and fit it nicely into the case.

[heavymachines]

Re: Seiki se421tt

its pretty thin panel i will check it out, good idea will report results...

[gilly1984]

Re: Seiki se421tt

its pretty thin panel i will check it out, good idea will report results...

Oh yh, you said led.

Still worth a try.

[heavymachines]

Re: Seiki se421tt

Nope still does it, shuts off with fan transformer still too hot and used a 120mm fan
..

[heavymachines]

Re: Seiki se421tt

and power board is all samxon caps could this cause the transformer to get hot? or something causing too much resistance and where to look?
thanks for any input

[heavymachines]

Re: Seiki se421tt

Nope still does it, shuts off with fan transformer still too hot and used a 120mm fan
..

well not near as hot as it was before the fan but what gives it weird it will run for few hours before shutoff...

[gilly1984]

Re: Seiki se421tt

well not near as hot as it was before the fan but what gives it weird it will run for few hours before shutoff...

Its probable nothing to do with the tranny.

You have replaced the psu so whats left? Never had an led before so no idea of the boards inside.

Does it have inverters? Im guessing not?

[tom66]

Re: Seiki se421tt

It will use about 90-150V to light the series strings of LEDs.

If a single LED fails, the TV will not run the backlight.

[heavymachines]

Re: Seiki se421tt

Its probable nothing to do with the tranny.

You have replaced the psu so whats left? Never had an led before so no idea of the boards inside.

Does it have inverters? Im guessing not?

no inverters, ..... hence led lol... it seems to be consistent at 2 hours.
the tv is not that old...

[tom66]

Re: Seiki se421tt

I'd think cold solder joint, tried using a hairdryer to heat up parts of the board and see when it cuts out?

[gilly1984]

Re: Seiki se421tt

no inverters, ..... hence led lol... it seems to be consistent at 2 hours.
the tv is not that old...

New to this ha ha, Kind of figured there wouldnt be inverters.

Try what tom says, if theres a person that knows, its tom.

What boards are in an led tv?

[gilly1984]

Re: Seiki se421tt

And just looked at that psu again, now,,, is it just me or are they making more simple things then charging us extra? Just that the psu look so empty?

[heavymachines]

Re: Seiki se421tt

And just looked at that psu again, now,,, is it just me or are they making more simple things then charging us extra? Just that the psu look so empty?

all three boards are small and fairly simple however like you i am new to led...I am aware of tom66 knowledge he helped me in the past, he is awesome help and i fully respect his suggestions and will apply those suggestions...Thanks tom66 i will try your suggestion when i get back to the shop in the morning...

[heavymachines]

Re: Seiki se421tt

also since its smart gonna check to see if shutoff timer er something dumb is set....

[infringer]

Re: Seiki se421tt

if one led fails they all fail? Interesting the old Xmas light syndrome that is just completely retarded imho... I actually opted for two LED TV's as an upgrade to the CCFL type for power savings how insane 1 LED goes out and it won't light up I suppose it isn't impossible to replace an LED but ... The real pain comes from getting to the backlight in the first place lol very poor engineering talk about a way to get you to buy a TV sooner lol at they rate they charge each LED should have a backup led in case one does fail.

[budm]

Re: Seiki se421tt

From the look of the power board, there are at least two LED strings for this TV which is typical.
For examples:
This 40" has 2 LED strings with 125 LEDs per string for edge lit panel.
http://s807.photobucket.com/albums/y...20UN40D5005BF/

32" with backlit panel. Two LED strings.
http://s807.photobucket.com/albums/y...2EH4050F%20TV/

[heavymachines]

Re: Seiki se421tt

I think it has 4 strings of led those 4 small matching connectors are for the led backlight.

[budm]

Re: Seiki se421tt

They should be labeled with something like DRV1+, DRV1-, DRV2+, DRV2-, etc.

[budm]

Re: Seiki se421tt

Which transformer that gets hot? The large one in the center or the top right for the PFC.