Hanns-G HG281D, LCD Monitor no power

[abeeftec]

Re: Hanns-G HG281D, LCD Monitor no power

Emergency question!

On the PSU, Between R403 and ZD406 there is a capacitor. It is capacitor 11 on the chart.

If I pulled a pad off removing that capacitor can I just solder that one leg of capacitor 11 directly to the leg of R403 and ZD406 or use one of those circuit pens to reestablish a connection or is my PSU finished?

This really sucks. I believe I pulled the pad right through the hole with the capacitor wire.


Does the leg closest to the outer edge of the PCB connect both R403 and ZD406 or does it only connect to R403?

I used Red and Blue pen in the picture to point at what I believe is traces connecting these three parts together.

Am I correct in thinking I can repair this or is this a done deal?

I was close to half done removing capacitors when this happened.

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

Am I correct in thinking I can repair this or is this a done deal?

It's fixable. Nothing too bad actually.

Just put in the cap and solder some thin copper wires to connect it to the two points beside it.

[abeeftec]

Re: Hanns-G HG281D, LCD Monitor no power

Another HannsG 28" Monitor saved from the trash heap!

I have got to say this forum is a great need for me.

I come across broken monitors all the time.

I popped two pads after removing 6 caps on the PSU board and was able to repair them using cap wires with a little help from this forum. Manipulating them in place without a magnifying lens in bad light with bad eyes was a bit tough but I managed.

So far the power button issue is gone and the fact that it even came on is absolutely promising! Now all I need to do is run it all day and let my brother game on it for a few hours and I will know if the snow issue is gone too.

But I suspect it will work fine since I replaced all the PSU caps except the ones under the aluminum cover and the two 100uF 16v caps on the mainboard.

You guys have been invaluable. Thank you!

Here is a picture of the monitor working

[abeeftec]

Re: Hanns-G HG281D, LCD Monitor no power

Another HannsG 28" Monitor saved from the trash heap!

I have got to say this forum is a great need for me.

I come across broken monitors all the time.

I popped two pads after removing 6 caps on the PSU board and was able to repair them using cap wires with a little help from this forum. Manipulating them in place without a magnifying lens in bad light with bad eyes was a bit tough but I managed.

So far the power button issue is gone and the fact that it even came on is absolutely promising! Now all I need to do is run it all day and let my brother game on it for a few hours and I will know if the snow issue is gone too.

But I suspect it will work fine since I replaced all the PSU caps except the ones under the aluminum cover and the two 100uF 16v caps on the mainboard.

You guys have been invaluable. Thank you!

Here is a picture of the monitor working

After running all day,
I had my brother play a game for a few hours, let it run some more, then checked all the inputs and speaker inputs as well to make sure everything is functioning.

I suppose I have a totally refurbished monitor now because it works flawlessly!

I always thought this monitor has a great picture and looks like an LED because of its ultra brightness. I also love the 16:10 Aspect ratio and 1200 resolution. Seems like it has more real estate than a 28" 16:9 aspect.


Again thank you guys for all your help and solid advice! I rarely find that on forums.

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

Another one for the "saved" list . Contratulations!

I hope I don't jinx it, but those 100uF 16V caps on the main board often give issues over time. But I guess if you start getting weird problems (particularly with resolutions or inputs), then you know what to change next . I mean, I really wouldn't go to such great lengths to keep telling you to change them if I wasn't sure that they are known to fail.

[lianger]

Re: Hanns-G HG281D, LCD Monitor no power

After lurking on the forum for the past two weeks, I manage to fix my HG281D with all the information everyone contributed. The screen was flickering none stop everytime it power on so I only replaced the caps on C80 and C83 main board it now back to normal.

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

Just a update i gave replaced the caps on main board 100uf 16v and now Wooking good. Thanks to all

[SADtherobot]

Re: Hanns-G HG281D, LCD Monitor no power

Hello all, thanks for the great information in this thread.

I have an issue which is a little bit different than most of the ones presented in this thread, but still similar overall.

The behavior I am seeing is that the monitor will just turn itself off or on at random. The LED on the front behaves normally, specifically:

- When the monitor display is off, the LED is off
- When the display is on, the LED is blue
- When the monitor is in standby, the LED is amber

A lot of the reports in this thread state that the LCD turns off, while the LED remains blue, but I have never seen this behavior.

The monitor can turn off after 5 seconds of uptime, or 10+ hours of uptime, there is no set value. The temperature does not seem to have any effect either. Pressing the power button will turn the monitor on or off as expected. Sometimes the monitor will turn off multiple times in a row, but after a few attempts, it will stay powered on for at least a few minutes (for example, 3 sec, 3 sec, 3 sec, 10+ minutes).

Furthermore, the monitor will turn itself on in the middle of the night and just sit there saying there is no signal (cause the computer is off).

This definitely sounds like a problem with the logic board, as I doubt the power board is controlling the on/off function directly (at least that's what it sounds like from reading this thread).

I see that a lot of people have been replacing the C80 and C83 caps on the logic board to resolve similar problems. Is it advisable to replace any other capacitors at the same time (specifically ones related to controlling the power on/off signalling)?

I examined the caps thoroughly in sunlight and I see nothing that looks discolored or bulging, but obviously the caps can still be bad. If it would be helpful, I can try to dig out my camera and get some pictures of it.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

The intermittent symptoms you describe definitely sound like caps. If it was C80 and C83 you'd get a fuzzy picture or distortion. (I'd still replace them because eventually they will go bad).....BUT......It sounds like the caps on the power board are your main problem. They start to dry up on the inside and show no signs of bulging.
I've repaired many of these. If this power board is the same as yours (there are 2 types used) then I'd replace the caps circled in red in my picture. (ones circled in blue are optional) The 2nd picture is the caps to replace on the main board. Picture provided, courtesy of Budm.

Let us know if that worked for you.

[SADtherobot]

Re: Hanns-G HG281D, LCD Monitor no power

Thanks for the information and the pictures.

I will order some replacement caps and swap out the ones marked in the pictures.

I will post my results once the procedure is complete.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

Thanks for the information and the pictures.

I will order some replacement caps and swap out the ones marked in the pictures.

I will post my results once the procedure is complete.

Sounds good. Go SeaHawks!

[SADtherobot]

Re: Hanns-G HG281D, LCD Monitor no power

Apparently my monitor has a newer version of the power board (Rev. 2 from 2009).

I saw 1 other person in this thread (algomez) with the same board and a similar issue, but he said the following:

"I replaced all caps with Panasonic FMs except for the huge one. Same symptoms..turns on fine for 15min or so then shuts off. Will turn on again then shut off after a couple of seconds."

I saw a post from PlainBill a few pages later stating:

"This type of power supply actually contains 2 supplies - the standby supply, which is always on whenever the monitor is plugged in, and the main supply which is turned on by one of the processors on the signal card."

This is why I originally thought that it might be a an issue on the signal/logic board, since it could be sending erroneous "power on" or "power off" signals to the power supply.

Unfortunately, I do not see another post from algomez mentioning whether replacing the caps on the signal/logic board had any effect on his issue, nor do I see his "final verdict" stating if he was able to get it working or not.


Any ideas which caps I should focus on on this power board?

Furthermore, does anyone know what components to check on the signal/logic board for the power on/off signal?

For reference, this is the power board I have:

[jetadm123]

Re: Hanns-G HG281D, LCD Monitor no power

Since you have 15 minutes before the monitor shuts down, try accelerating the shutdown process by heating up both boards with a hairdryer. Try heating the logic board first. I believe there are two caps on the logic board that tend to cause problems. They're mentioned several times in this thread. Try heating those two caps.

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

This is why I originally thought that it might be a an issue on the signal/logic board, since it could be sending erroneous "power on" or "power off" signals to the power supply.

Unfortunately, I do not see another post from algomez mentioning whether replacing the caps on the signal/logic board had any effect on his issue, nor do I see his "final verdict" stating if he was able to get it working or not.

Change the caps on the logic board regardless. C80 and C83, IIRC, are the biggest offenders. The mostly cause a messed up imagey, but I wouldn't be surprised if they were responsible for a no-power issue as well. Read this post after the second quote, where it says, "yes":
https://www.badcaps.net/forum/showpo...&postcount=604
If you are making an order from online and paying a good amount of shipping, you might as well buy replacement caps for the power supply too. That is, replace all caps on the power supply except for the big one. Sooner or later, this monitor always needs it.

[Galaxis]

Re: Hanns-G HG281D, LCD Monitor no power

Hello everybody

I am french, and is my first post here.
Registering today, 12/06/2014.
after read the all post on the HG281D, no power,

I disassembled my HD281D several times, and change all capacitors
main namely:
Between Cooler C601 C406 C701 C403
Right C502 C301 C505 C302 C506 C306 C401 C702
all caps 105C.
After reassembling the screen still remained off,
I could turn it with shocks electrical outlet.
But now impossible to restart
I have a ESR tester (http://fr.aliexpress.com/item/Digita...869640902.html )
I test the other capacitors namely:
C603 C606 C707 as explained by "retiredcaps" a big thank you to you.
and I found that the C603 was with my HS test.
Replacement with an old 22uF 40v 85C waiting for a new command
After reassembling the screen is gone and still works great thank you to retiredcap and
Mishannya for nice pictures.

Thanks everybody

[itrader]

Re: Hanns-G HG281D, LCD Monitor no power

Change the caps on the logic board regardless. C80 and C83, IIRC, are the biggest offenders. The mostly cause a messed up imagey, but I wouldn't be surprised if they were responsible for a no-power issue as well. Read this post after the second quote, where it says, "yes":
https://www.badcaps.net/forum/showpo...&postcount=604
If you are making an order from online and paying a good amount of shipping, you might as well buy replacement caps for the power supply too. That is, replace all caps on the power supply except for the big one. Sooner or later, this monitor always needs it.

Thanks to all who posted here, my monitor would shut down if it got to hot in the room, put a fan behind the monitor on full blast that would keep it going, but its getting really hot this week and even the fan wouldnt keep it on.

I replaced c80 and c83 on the logic board and all is well!! working great.

Thanks to everyone

[Samsara]

Re: Hanns-G HG281D, LCD Monitor no power

Great to hear! You're welcome.

If you start getting any video problems like shimmering, color shifting, or fuzziness you'll need to replace the "two 100uF 16V by the regulators on the main board" as budm recommends in post #593. Those are usually the other capacitors that go bad.

Hello again, after a short stint at working fine, the monitor I recently replaced caps for is now suffering further problems. The power button works after replacing some caps but now the screen's problem of going black for a few seconds every now and then has gotten worse. It's going black and staying black for a long time now and its left the monitor unusable again.

I'm going to change the two caps on the main board that have been repeatedly mentioned before, but I am not sure if my blacking out screen classes as flickering/shimmering, which those caps are supposed to fix. Maybe it's something else?

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Haha you changed the post, thought I had gone mad - The 2 caps C80 and C83 are on the main/logic board which is the one with the blue vga socket on it.

Whilst it is not usually a symptom its best to change those two caps - gives a level playing field to start tests, and you never know your luck it may fix it.

First thing after that would be to go over your previous work with a magnifying glass
and check for any poor joints reflowing them as required.

When the picture is black can you still see anything at all on screen by using a torch
shining at different angles - useful if you know what pic it being displayed then you know what to look for as it will be very dim if there at all.

[gordesky1]

Re: Hanns-G HG281D, LCD Monitor no power

Hi guys i have a problem with my Hanns-G HG281D to.

But heres what happens the buttons are wacky like i cant turn down the brightness unless i wait 5secs in between presses which i got it down to 90, But sometimes when doing it, It will go back to 100%.

Than when on for like 10mins there's white artifacts dots blinking on some colors...

Pretty much im having this problem like this guy has https://www.youtube.com/watch?v=2iOZz-_sK8o

Go to 5.11 for the buttons problem and 6.15 for the white dots.

And sometimes it will go off and on but the blue light will still be blue.

Would the cause be the C80 and C83 caps for my problem?

This started like 2years ago and hanns never got back to me for the warranty, So i bought another 27inch monitor and put this one in the box and left it sit. And today i figure i see what the problem is.

I took it apart and see no damage caps, But than herd they don't have to be bulging to be bad.

thanks

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

See post 629 if your board is the same replace the caps as marked and also the 2 on the
main board. It could be a no brainer fix but if it doesnt fix it, it rules out a lot of possibilities.
The symptoms do sound main board related, but it could be other things, so if you want to pay postage twice just replace those 2 caps.
You need to use good caps from a known good supplier - lots of fakes on ebay though
some are known to be ok.