Hanns-G HG281D, LCD Monitor no power

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Hi - welcome to the forum-
We can help a lot more if you post good clear pictures of the whole chassis, and then straight on pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

It will be useful if you can say what the supposed fault was and a bit about yourself - skills tools etc. Do you have a multimeter and soldering equipment and can you use them.

When you get inside look for bulging or leaking capacitors, burn marks etc and report what you find

[HostileHST]

Re: Hanns-G HG281D, LCD Monitor no power

I was just given a hg281d which is not working, every so often when i press the power button i get a little flicker of blue in the bottom right power light but I have not managed to get anything else out of it, Is there anyone out there willing to try to help me threw this, if so I will take some picks tomorrow of the boards inside.. this will be my first attempt at fixing a problem like this so it might take baby steps. The monitor is beautiful, owned by a old lady that prolly never even put a fingerprint on it. she just bought a new monitor and that's how i got my hands on this

It's a long thread, but start from the beginning like I did and you should find the answers (with pics even). Generally, the capacitors on the output side of the power supply go bad and in my case it was those and a cap on the 5v stand-by line as well. Again, read the whole thread, yes lots of stuff to read, but I am sure you will have that thing fixed pretty quick as long as you have access to parts. Oh, just cause you can't see any visible damage, doesn't mean the caps are good. I think most of us have run into that with these monitors and I personally have with tons of electronics.

[charleseo]

Re: Hanns-G HG281D, LCD Monitor no power

Thanks, I'm excited about the fast reply. I have been going thew this thread studying up on a bunch of different symptoms and fixes. I am optimistic about the work that lies ahead. I have no experience saddening or anything like that but I have a steady hand and so far I seem to be able to do anything with good instructions. I am at work now but as soon as I get off I plan to get out the camera and the lights and take some high quality pictures for everyone to study. Again thanks for the quick reply ill be back this evening.

[HostileHST]

Re: Hanns-G HG281D, LCD Monitor no power

Thanks, I'm excited about the fast reply. I have been going thew this thread studying up on a bunch of different symptoms and fixes. I am optimistic about the work that lies ahead. I have no experience saddening or anything like that but I have a steady hand and so far I seem to be able to do anything with good instructions. I am at work now but as soon as I get off I plan to get out the camera and the lights and take some high quality pictures for everyone to study. Again thanks for the quick reply ill be back this evening.

Your welcome! Assuming you have a soldering gun, pick up some solder wick, very helpful for pulling parts. A solder sucker works also, but personally, I find it not as good as solder wick, but that's a personal thing. Cost about $3-$4 at the shack, but I recently got lucky and picked up 6 rolls from a mom and pop store for $6 total. Plan to get more since I use a ton of it and at a $1 a pop, I should buy them out, hehe.

[liqshot]

Re: Hanns-G HG281D, LCD Monitor no power

Hey guys, new to the forums but I have a Hanns-G HG281 and I had a fuzzy screen for a while so I finally had the time and took it apart. I took a look at everything and I found an area on the logic board where it was burned. I put everything back together and now it doesn't even power on. Any help would be greatly appreciated. Pics below of power board and I'm assuming that is the problem

[Vizor]

Re: Hanns-G HG281D, LCD Monitor no power

Anyone have a issue where the monitor likes to go off every so often then come back on by itself like 10 secs later?

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

@liqshot Welcome to the forum.

That has to be one fo the worst requests for help that I have seen for some time.

Have you read this thread

Have you done any of the tests

3 or 4 posts above yours I have gone to great lengths to explain how to load pictures, yet you post in line and cut off the edges.

You say you found a burnt part but you dont say what you did about it.

It looks like some resoldering is required but you dont say if you have the tools or the ability.
We will need to see all the boards.

[Recycler]

Re: Hanns-G HG281D, LCD Monitor no power

Anyone have a issue where the monitor likes to go off every so often then come back on by itself like 10 secs later?

Yes. Post pics of the logic board.

Cheers.

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

I was pointed to here by retiredcaps (in this thread) and I've just opened my monitor (HG281D Made in Jul 2008) and taken pictures of the power board.

That square black thing (is it a transistor?) at Q601 on the bottom side, in the middle at the side of the board seems pretty darkened.

Is it perhaps that which is causing my monitor to not switch on properly?

All the capacitors look fine and I can't see any bulges.

As for equipment I have a standard multimeter (Sinometer MS8230B) and a soldering iron and solder + copper braid and a suction gun.

Is it just a case of replacing all the capacitors on the power board?

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

I have brought the problem forward so people dont need to keep looking

This monitor is 3 years old now and the problem I have with it is when it goes to sleep (computer off no video signal) it will sometimes turn itself on (LED Blue) and then go into standby (LED Orange) and then switch off (No LED light).

It'll just cycle through that while it's plugged in and left on.

However when I want to use it, if the LED isn't blue at the time it can take up to 20-30 minutes for it to turn on by itself.

Once the monitor is on it works fine and there are no problems until I turn off the PC or the monitor goes to sleep.




Q601 doesnt look too bad on the other hand Q502 looks like it needs resoldering- perhaps a close up pic of both? And if you can post the part numbers of them.
There looks to be a few iffy solder joints on the board. Go over them with a magnifying glass and retouch any that you think may be cracked or cold.
Can you get the rest of the heatsink off?

From a cold start switch it on and heat the caps on the power supply with a hairdryer to see if it comes on any quicker.

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

Hi selldoor,

Will post pictures tommorow when there's more light to take some.

Q601 has DFRW printed on it.
Q501 has FR3707Z on the first line, I then it has a diode symbol and RP745G
and then M6 FT on the last line.


As for getting the heatsink off if you look at the third picture on the right where the blue part is under the green thing (sorry I don't know what they're called ) there is a screw through a flat black thing soldered onto the board.

That screw is being blocked by the blue thing and if I could get access to the screw I could remove the heatsink on that side.

I've gone over the board with a magnifying glass and I can't see any moving or cracked joints.

[liqshot]

Re: Hanns-G HG281D, LCD Monitor no power

Hey sorry guys its been a while and I knew that my pics were not of good quality but I did manage to change the caps and its powers up no problem.. Vga works but has flickering and the hdmi works for about 10-15 seconds and goes blank. But if I unplug it and let it rest for 30min-1hr, it will pop back on for 10-15 seconds. Inbetween that rest period it wont show anything with hdmi. Sounds like a logic board problem? If so, what are some things that can cause this type of issue besides bad capacitors?

[retiredcaps]

Re: Hanns-G HG281D, LCD Monitor no power

Hey sorry guys its been a while and I knew that my pics were not of good quality

Somewhere in 250 posts, PlainBill and I have mentioned in numerous occasions (even my sig file reflects) that we prefer pictures uploaded here and done using manage attachments. For a number of reasons, we dislike inline pictures and offsite hosting.

but I did manage to change the caps and its powers up no problem..

Did you recap the main board?

https://www.badcaps.net/forum/showpo...&postcount=123

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

Q601 doesnt look too bad on the other hand Q502 looks like it needs resoldering- perhaps a close up pic of both? And if you can post the part numbers of them.

From a cold start switch it on and heat the caps on the power supply with a hairdryer to see if it comes on any quicker.

Here's those pictures I promised.

I'm going to have to unsolder that blue rectangle item at the end to get to the screw on the mosfet so I can remove the rest of the heatsink.

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Ok thanks your right Q601 has run hot

Ill Try and find something out about them

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

Ok thanks your right Q601 has run hot

Ill Try and find something out about them

Q501 and 502 are the same part number

FR3707Z on the first line, I then it has a diode symbol and RP745G
and then M6 F1


The last character is a 1 not a T as I mistakenly posted previously.

The Q601 only has DF RW and the circle in the middle of it is too small to read even with a magnifying glass.

Also managed to take the heatsink off by removing that blue resistor. All the caps look fine to me.

I was actually hoping to find a bulged cap so it'd make it easier for me to go "that's the problem" but this is even worse

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Hi Q501/502 are Mosfets the diode sign is the manufacturers logo I believe.
The data sheet is attached.

As for Q601 I cant find a sheet on it however I believe it to be a transistor/mosfet so all three can be tested as follows:
"Mosfets

If you have a manual range multimeter, set it to 200 ohms (two hundred). This is for 3 pin ICs only. You can test a mosfet (Q, IC designation) "in circuit" by (power off and unplugged)

a) black on pin 1- red on pin 2 - record ohms
b) black on pin 1- red on pin 3 - record ohms
c) black on pin 2- red on pin 3 - record ohms

If any reading is less than 30 ohms you might have shorted mosfet. Remove from circuit and repeat the tests to verify."
This is from Retiredcaps 2 seconds to black guide which contains other tests and well worth reading. https://www.badcaps.net/forum/showthread.php?t=10419 start at post 19

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

You will need to replace "that blue rectangle thing" - it is a capacitor- board ref C1.
It will be ok to run the board for short periods without the heat sinks.
Did you get to try the hair dryer trick?.
Next tests will be DC voltage tests first while the board is coming on but not on
then again when it is on.

[psmedley]

Re: Hanns-G HG281D, LCD Monitor no power

I was actually hoping to find a bulged cap so it'd make it easier for me to go "that's the problem" but this is even worse

I just fixed a 32" plasma. Two caps were bulged - another half a dozen or so were not bulged - but were still bad.

An ESR meter is a good investment to determine whether caps are bad or not.

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

You will need to replace "that blue rectangle thing" - it is a capacitor- board ref C1.
It will be ok to run the board for short periods without the heat sinks.
Did you get to try the hair dryer trick?.
Next tests will be DC voltage tests first while the board is coming on but not on
then again when it is on.

I've still got it, I was planning to solder it back on or do I need a new one?

Haven't got to doing the hair dryer trick, have to set up the monitor so I can see it and have access to the back to blow the hair dryer on it but it's been tricky.

I just fixed a 32" plasma. Two caps were bulged - another half a dozen or so were not bulged - but were still bad.

An ESR meter is a good investment to determine whether caps are bad or not.

Searching for an ESR meter online the lowest price I can find is one for £85
If I had to repair lots of monitors I'd definitely get one.

Reading that post by retiredcaps selldoor. Will do the tests on the mosfets and report back and hopefully get the hairdryer test done.