Hanns-G HG281D, LCD Monitor no power

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Yes it should still work with those caps unless they are total duds.

Just to be sure, you did put them in the right way round?


Are you sure the cable from the main board to the panel is connected?

[jleon92f]

Re: Hanns-G HG281D, LCD Monitor no power

Yes it should still work with those caps unless they are total duds.

Just to be sure, you did put them in the right way round?


Are you sure the cable from the main board to the panel is connected?

Yes, I did install the cap polarity the right way. +/- ..!

I reconnected everything! And it WORKS GREAT! No more flickering! Comes on right away! Thank you guys for all your help!

John.

[Ralph Schraven]

Re: Hanns-G HG281D, LCD Monitor no power

Hi all,

just to say thank you - you saved my week

Changed the two mentioned caps on the logic board and everything is fine.

In first assembly I only got vertical coloured stripes on the screen, but this was due to a loose connector between logic board cable and panel.

Many thanks

BR

Ralph

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Glad to hear the successful repair.

[vixensjlin]

Re: Hanns-G HG281D, LCD Monitor no power

Great discussion -- here is another Hanns-G HG281D with no power.

I bought a Hanns-G HG281D in January 2007 from NewEgg. Recently It became very hard to turn on and now it is complete dead -- no blue or orange light LED no matter how many times I press the power bottom. I couldn't measure the voltage with a live PC, but I tried to measure the PSON voltage at the first second it connect to 110VAC power -- PSON is about only 0.05V regardless of pressing power bottom. It was very hard to measure voltage with the 30pin connector link to the monitor so I detached it for measurement. When I detached the power chord, after a second PSON voltage jumped to ~0.3V and returned back to 0V.

Any guessing where did it went wrong? Really appreciate your input!

[jetadm123]

Re: Hanns-G HG281D, LCD Monitor no power

Great discussion -- here is another Hanns-G HG281D with no power.

I bought a Hanns-G HG281D in January 2007 from NewEgg. Recently It became very hard to turn on and now it is complete dead -- no blue or orange light LED no matter how many times I press the power bottom. I couldn't measure the voltage with a live PC, but I tried to measure the PSON voltage at the first second it connect to 110VAC power -- PSON is about only 0.05V regardless of pressing power bottom. It was very hard to measure voltage with the 30pin connector link to the monitor so I detached it for measurement. When I detached the power chord, after a second PSON voltage jumped to ~0.3V and returned back to 0V.

Any guessing where did it went wrong? Really appreciate your input!

Try checking the main fuse. It's appears to be the small brown block (should be marked FXXX, where XXX is some number) below the AC input connector on the lower left of your photo. Make sure your monitor is unplugged when performing this check.

If the fuse checks ok, with the monitor plugged in, measure the voltage across the main 450V cap. You should read approx. 390V DC.

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Check the DC voltage right at the two legs of the 450Vdc cap, it should have about 165~170VDc on it when the monitor is in standby, then go to 380~390Vdc when you activate the power switch, if you do have 165V, then the main fuse is OK. next, we need to find out if you have standby voltage.
Warning: You will be working in the primary (deadly) side, so do not touch anything on the board wit your hands. I would plug it into GFCI outlet while you are working on it.

[vixensjlin]

Re: Hanns-G HG281D, LCD Monitor no power

Thanks a lot! But I am very rudimentary on this. To confirm that I don't misunderstand two parts you are talking about ( main fuse and main 450V cap), I label the picture again.

Does the red arrow point to main fuse? Does the blue line circles main 450V cap? thanks again!

[jetadm123]

Re: Hanns-G HG281D, LCD Monitor no power

Correct.

[HostileHST]

Re: Hanns-G HG281D, LCD Monitor no power

You should be able to follow the 5v standby voltage to one of the smaller caps in the center part of your power supply (where C114 is). It was one I had to replace when my hannsg was dead several months ago, but I was at least getting a lit front LED. Beings I still use the monitor on my main pc here, I'd rather not take it apart to trace which cap the 5vdc standby goes to, but if memory serves right, it's the lower 3 on your picture in the center there where C114 is. Is the cap beside C707 swollen? Sort of looks like it.

[alrj]

Re: Hanns-G HG281D, LCD Monitor no power

Sorry for updating an already old and neverending thread, but I just finished repairing my HG281D.

After 3 or 4 years of service, it had developped all the symptoms. The lower part of the picture was often flickering. I had to spam the power button to turn it on, and it then alternated between "on" and "black" for a good 20 minutes. Once it was on, it would stay on for days or weeks.

A few days ago, after a power cut, it wouldn't come back on anymore. I replaced all caps on both PCB except for the 450V at the input, connected the power cord and... YAY! Turned on immediately, no magic smoke :-) no flicker, perfect image.

Thank you everybody.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

Thanks for the feedback! Great to hear another nice big 28" monitor was saved from the scrapyard. It's great to watch a totally dead monitor come back to beautiful colorful life

[kreative]

Re: Hanns-G HG281D, LCD Monitor no power

I hope I can get some help here if this thread is still alive.. =)

Symptoms, Unable to power in, no blue LED nor orange LED light.

when logic card disconnected, +5VSB: 4.96V, PSON near 0
when logic card connected, +5VSB: 4.15~4.20, PSON near 0

any help will be greatly appreciated.

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Any bulging caps on the power supply board? You can try changing, they should be changed anyway, the two 100uf 16v on the main board, see post #428 it has the link to my pictures of the caps.
https://www.badcaps.net/forum/showth...=11329&page=22
Make sure you have it hooked up to running PC.

[kreative]

Re: Hanns-G HG281D, LCD Monitor no power

Any bulging caps on the power supply board? You can try changing, they should be changed anyway, the two 100uf 16v on the main board, see post #428 it has the link to my pictures of the caps.
https://www.badcaps.net/forum/showth...=11329&page=22
Make sure you have it hooked up to running PC.

No bulging caps. monitor just unable to switch on at all.
the 2 caps u mention are on the logic card, am I right?

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Yes. Bad cap can look normal but can have high ESR. Those two caps on the main board show correct capacitance, but the ESR is almost 10 Ohms, and no sign of bulging either. Did you see the link?
http://s807.photobucket.com/user/bud...?sort=3&page=1

[kreative]

Re: Hanns-G HG281D, LCD Monitor no power

Yes. Bad cap can look normal but can have high ESR. Those two caps on the main board show correct capacitance, but the ESR is almost 10 Ohms, and no sign of bulging either. Did you see the link?
http://s807.photobucket.com/user/bud...?sort=3&page=1

Alright, I'll change them out and give it a try.. update again tomorrow.
Thanks

[kreative]

Re: Hanns-G HG281D, LCD Monitor no power

Alright, I'll change them out and give it a try.. update again tomorrow.
Thanks

i have changed both the 100uF cap, its not powering on either..

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

A set of caps for the power supply will be next.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

i have changed both the 100uF cap, its not powering on either..

Ok kreative. I have posted this several times. Maybe it's hard to read through such a large thread. No problem. If you replace the caps circled in red and the ones circled in blue. It should start up again