Iiyama Prolite E481S goes dark after 1 second, blue power LED steady on

[enghijjawi]

Hi!

Everytime I switch the flat screen on, it goes dark after a second. The power LED, however, stays on (constantly blue, not flashing) all the time.
i have Iiyama LCD monitor when i turned it on


I read all the posts at https://www.badcaps.net/forum/showth...ighlight=e481s


I like repairing the screen based on the schematic and follow the read voltages and compare them to see the defect.
i spent long time Looking for the schematic of LCD screen E481S, including the planned site of http://www.elektrotanya.com and unfortunately I did not find anything.

I hope he has the experience to help me

Thanks alot for all

[enghijjawi]

Re: Iiyama Prolite E481S goes dark after 1 second, blue power LED steady on

Hi
i think no one tried to download E481 iiyama schematic(service manual) cause i spent much time searching with no result.

could anybody please tell me or send me its schematic or service manual

thanks to all

[enghijjawi]

Re: Iiyama Prolite E481S goes dark after 1 second, blue power LED steady on

sorry for my english cause arabic is my native language.
welcome to the forums

[PlainBill]

Re: Iiyama Prolite E481S goes dark after 1 second, blue power LED steady on

1. Don't double post. It's hard enough keeping track of people needing help without having to repeat myself. I ignored the post in the other thread because you didn't include pictures.

Your problem is 'two seconds to black'. Usual causes are bad capacitors or bad CCFLs. The gentleman in the other thread had a bad solder joint. Have you checked that?

PlainBill

[enghijjawi]

Re: Iiyama Prolite E481S goes dark after 1 second, blue power LED steady on

thanks for your interest
these pictures for my fault board.

[PlainBill]

Re: Iiyama Prolite E481S goes dark after 1 second, blue power LED steady on

thanks for your interest
these pictures for my fault board.

Hmm, made by Samsung.

1. What brand of capacitors are these?

2. I would like a picture like the first, but of the back side of the board.

PlainBill

[enghijjawi]

Re: Iiyama Prolite E481S goes dark after 1 second, blue power LED steady on

Thanks for your note and sorry for that error
Actually, where was the images of the LG screen. If you remember the first to post on the schematic of this screen.

These new images for the screen iiyama

Thank you and thank all the forum.

[PlainBill]

Re: Iiyama Prolite E481S goes dark after 1 second, blue power LED steady on

I've marked up and attached the pictures. First, several comments.

1. When I saw the jumper across the fuse, I ALMOST decided to ignore the thread. Bypassing a fuse is a very foolish thing to do.

2. When I view pictures of the top and bottom of a board, I prefer to correlate left-right. It is more difficult to correlate top-bottom. It is pure HELL to try to correlate when the pictures are rotated 90°.

3. The picture of the top was quite good - I can even read component identifiers without expanding it. The picture of the bottom was almost useless. Even expanded to full size I can't read most component identifiers.

This monitor uses an inverter design called a Royer oscillator. It is readily recognizable by the large poly cap between the paired transistors and the inductor. The strengths of a Royer oscillator are the low component count and the high efficiency - it's a tuned circuit. The weakness of a Royer oscillator is the transistors are destroyed if anything goes wrong. This monitor has two Royer oscillators and a single control IC (on the bottom). The control IC will shut down both oscillators if either is not working properly. Individual transistors turn each oscillator on and off.

On the top I've circled the jumper across the fuse in red. Remove the jumper and replace the fuse.

I've circled one transistor in pink. That appears to be larger than it's companions. The transistors must have identical electrical characteristics. If one fails, ALWAYS replace both.

Common problems with a Royer oscillator are bad solder joints on the transformer, bad solder joints on the inductor, and a bad tuning capacitor. I've circled these in green. The control transistors are on the bottom of the board, circled in red. There is also a diode in each oscillator that can fail, I THINK it is next to the transistors on the bottom, but I couldn't be sure.

PlainBill