Hanns-G HG281D, LCD Monitor no power

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

So, if I use the hardrayer to switch on the monitor every day (at least until I find someone with a good 60w soldering iron...), do you think I can damage something?

Not on this monitor - or so it seems from other's people's posts here. That said, the bad capacitors in your monitor are only going to get worse over time. So don't be surprised if one day your monitor doesn't work at all, even with the hair dryer.

Also, on other PC equipment, such as power supplies, motherboard, and video cards, NEVER ignore bad capacitors, because they often WILL cause damage.

Now the bad new is I haven't the soldering iron to make the work and I haven't money to spend for a new good one with also the rosin flux

You can find very cheap soldering irons on eBay, like this one:
http://www.ebay.com/itm/Useful-AC-22...6Ot4Gn4JCnXKbA
or this
http://www.ebay.com/itm/U-Choose-60W...jk0umTIMhsLWuw
Their quality is low, but should work for the occasional use like you need.
Rosin flux can also be found in that second link for US $1.

Most likely, you should be able to find these same items above on eBay.it
Hopefully, shipping should be free to your country as well.

P.S.: I read in this forum about one person who made the work with a 20w soldering iron, perhaps He was only lucky and his board was soldered bad by the factory?

If you are skilled, your 20 Watt iron may work for the power supply board capacitors. But certainly not for the logic board. If you have a heat gun tool, you can pre-heat the parts of the power supply board to about 50-60C before trying to solder on it. I used to do that quite often when I only had a 30 Watt iron before. A hair dryer might work for the pre-heating too.

Anyways, my suggestion for you would be to go ahead and buy the replacement capacitors now, regardless that you don't have a good iron. That way you can have them ready so that when the monitor fails, you can at least try to change the ones in the power supply with your 20 Watt iron. Your monitor really is working on borrowed time here.

*edit*
Seems like the soldering irons are more expensive in your country on eBay.it
Still, here's a few that I found that are worth about the same as your 20W iron:
http://www.ebay.it/itm/60W-220V-Penc...UAAOSwzgRW0Hxx
http://www.ebay.it/itm/1499351-HH601...sAAOSw3mpXJBho
(note that the second one is for 110V, but see if you can find one for 220V/230V for your country.)

[N_R_G]

Re: Hanns-G HG281D, LCD Monitor no power

@momaka

Hi, thank you for your answer and also for the tecnical explanation about the function of the ESR of electronic capacitors with differents temperatures... I very appreciated it

Now the bad new is I haven't the soldering iron to make the work and I haven't money to spend for a new good one with also the rosin flux

So, if I use the hardrayer to switch on the monitor every day (at least until I find someone with a good 60w soldering iron...), do you think I can damage something?

P.S.: I read in this forum about one person who made the work with a 20w soldering iron, perhaps He was only lucky and his board was soldered bad by the factory?

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

Hi N_R_G, welcome to the forums!

No need to apologize for your English, I understood your post very clearly .

About the monitor troubles you have:

So it's seems as a component needs to be heat to avoid the monitor to have elettricity power again
...
And so what I ask, do you think my issue is due by caps in question?

YES, this is likely a classic "start-up" capacitor issue. See post #629 here:
https://www.badcaps.net/forum/showpo...&postcount=629

The reason this happens is because as the temperature increases, the ESR of an electrolytic capacitor decreases. As caps age, their ESR increases and they may become marginal for the circuit they are in. But once heated up, their ESR may drop just enough for the circuit to work again. Hence why when it's warmer, your monitor works, but not when it's cold.

I have a 25W solder (cost € 15,00) , and I tried with an old pc motherboard to desoldering some caps without any results...

PC motherboards can be very hard to solder and that 25 Watt soldering iron is not good enough. You need 40 Watts minimum. If you never have soldered before, I recommend 50-60W.

The monitor's power supply won't be that hard, so a 50 Watt iron will work for that. But the monitor's logic board will be tougher: not as much as a PC motherboard, but more than the single-sided PCB of the power supply.

So ideally, you will want a 50-60 Watt soldering iron. Also get some rosin flux (liquid or gel are both OK). It will help you a lot. Just apply to joints before heating with your iron.

[N_R_G]

Re: Hanns-G HG281D, LCD Monitor no power

Hi to all members of this fantastic community. I'm new here and I hope you can help me to solve my problem.

Before speaking of my problem, I state that I have read the whole discussion, even if painfully, seen my bad english ... Now coming to my problem, I 'm also a holder of this fantastic HG281D, who stopped to go on (no
power) since an year ago.

During the cool season with 16° celsius (60,8° F) in my ambient, nothing worked, but before, during the summer with 30° celsius (86° F), the monitor, after many hours (24h) was linked to the elettricity It turned on by himself.

Now I have 23°celsius (73,4° F) in my room, I discovered that if I use an hairdryer to Heat the monitor through its air grilles after 3-5 minutes the monitor go on again...

So it's seems as a component needs to be heat to avoid the monitor to have elettricity power again...

Before try to change the 3 caps (signed in red in this thread) of the power supply I want to be sure to be able to make the work...

I have a 25W solder (cost € 15,00) , and I tried with an old pc motherboard to desoldering some caps without any results... so now It's very difficult for me Think of putting Hands into the Power Supply of the Monitor...

And so what I ask, do you think my issue is due by caps in question?

I see many video on youtube to desoldering caps, but I hadn't any results on my motherboard... so any suggestion?

PS: I know my english is very bad, (i'm italian) so excuse me for my bad use of your language... sorry


NOTE: I am still writing through my HG281D turned on Through the use of the hairdryer; if the computer remain on, the monitor works well, but if I turn off the pc after half an our, the standby yellow led turn off, so I need again the hairdryer to heat the monitor and use it again

[kadi144]

Re: Hanns-G HG281D, LCD Monitor no power

many thanks for all

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

I add more solder to the joints and use Flux when trying to remove the caps using 60W iron with wide tip.

[minodevbc]

Re: Hanns-G HG281D, LCD Monitor no power

Like in the quote below, I'm having a helluva time removing caps from the logic board. I'm using a Stahl iron and kept cranking it up until it's maxed at 450deg C, my tip is turning brown despite repeated tinning, and it still takes a minute or so of contact to melt the original solder on the logic board. In fact, the leads are melting out of the caps before the board solder melts. It's getting really hot, but the old solder's just not melting.

I'm using a well-tinned tip with repeated cleaning and a dab of solder on the iron to conduct the heat. Any advice? I'm worried about damaging other components on the board with the heat. I had no trouble at all with the power board at a much lower heat setting.

I scanned HG281D repair posts best I could and didn't see this issue mentioned. There are a ton of HG281D posts, though, so I apologize if it's been addressed elsewhere.

Thank you for the infos!

Now, I thought I would attempt the soldering part but honestly, I have embarrassed myself simply removing the capacitors in question. I really thought this to be much more easier than it really is.

First of, I am using the Wall-Lenk LSP-110 soldering iron.
The specs list the heat output to be between 30-125W,
reaching temps between 410-750 deg Celsius.

I watched one of the online YouTube videos of how to remove a capacitor and they guy states that a temp setting of 450 would be fine and the entire process seems to be a piece of cake. However, the particular board I am working on is anything but easy to work with. I tried removing the capacitors but the legs seem to literally be wedged in the tiny holes. I had a needle-nose on one side, the soldering iron on the other and the leg seemed lose, however, it would not come out easy at all. The legs are set pretty darn firm and I broke of half of them trying to get them out. One whole in particular I am having a hard time of cleaning it out. I'm lost and I thought I would be somewhat gifted with motor skills. Maybe I am not, or maybe it's truly the board that's so difficult to work with.
Well, I will have to see how to get it out now. I watched several online tutorials and read some posts here, but nothing really seems to help quite well and easy.

As for the new capacitors, I tried a search last night on DigiKey, but the site's search function was down. I will try again today and hope to be able to order the right parts.

One more question: The second person posting an issue with the power & logic board at the beginning of this thread states almost the same issues. He has powering on problems. Once on, the screen is fine. Somebody suggested the main capacitor that gives the initial start charge having potentially an issue. I am not sure if I am translating correctly here. But if it makes sense, the main capacitor on the power board is under a heat sink that is soldered in, am I correct? Will that hit sink have to be removed by unsoldering it? It sounds obvious to me, but maybe there is an easier way out. Thanks!

Thanks again for all of your help!

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

I only changed those 3 poor quality caps, which was changed by monitor repair man. I did not change those Panasonics I did a year ago.

Are those pictures you just posted from the new repair? If yes, please tell your repair man not to use those green Teapo SC capacitors. Otherwise, you will be seeing him again next year.

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Ah yes, those caps on the logic board. Thanks.

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

I only changed those 3 poor quality caps, which was changed by monitor repair man. I did not change those Panasonics I did a year ago.

And my other problem also solved. Those white filckering pixels around or I have no idea what they were... Atteched pics.

So everything is perfect by now.

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

I fixed it. It works fine, better than ever.

Thank you very much again.

So you changed all the caps again with better quality one?

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

I fixed it. It works fine, better than ever.

Thank you very much again.

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

Please check my post #727.
I changed everything a bit more than a year ago.
Do you think I should repeat the whole process again?

That would be this one, I suppose:
https://www.badcaps.net/forum/showpo...&postcount=727

My answer to your question above is YES and NO.

Yes, repeat the process of changing ALL of the capacitors that you changed last time.

No, do NOT use Yageo / Teapo capacitors again. Yageo / Teapo (especially the SC series, which you showed us in this picture) are an extremely poor choice for monitor use (and for anything, actually - Teapo is often said to be as bad as CapXon around here... and CapXon is well known to fail regularly).

Use only quality *Japanese* capacitors (i.e. Panasonic, Nichicon, Rubycon, and United Chemicon), and make sure to pick a low-ESR series as well. Avoid eBay and local stores for buying capacitors - most Japanese caps there are counterfeit. I see that you are in Europe (Hungary), so I guess you can buy your caps from either RS Components, Farnel, Badcaps.net, or contact member Behemot here (he's based in CZ, IIRC).

Speaking of low-ESR caps, here is an updated list of series that you can use:
https://www.badcaps.net/forum/showpo...22&postcount=9

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

Please check my post #727.
I changed everything a bit more than a year ago.
Do you think I should repeat the whole process again?

Or at least I should change those 2 even If they are not older than 1,5 years?

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

Thank you.
I will do it, than I will let you know the result.

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Try changing those two caps on the logic board first:
https://www.badcaps.net/forum/showpo...&postcount=783

But the power supply should also be re-capped.

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

Hi,

I have some problem with my HG281D. It started to go black than works fine for a sec and than goes black again, and it circling till warm up.
Anybody has any idea?

Regards,
Castor

[kumasan]

Re: Hanns-G HG281D, LCD Monitor no power

Per previous post, attached photo of the problem with the yellowed screen after recap.

The second photo shows some artifact from the camera (does not look this way) but the pattern seen by camera might shed some light on the problem.

Any ideas as to what to check next appreciated.

Thanks,
Kuma

[kumasan]

Re: Hanns-G HG281D, LCD Monitor no power

Have one of these HG28 monitors that went out. Started with the power supply and replaced all caps with panasonic's. Did not fix the problem.

Next I replaced the three big caps on the logic/control board, followed by the five 100uf caps which brought the monitor back to life but not 100%. Problem now is that the colors seem off and the center of the display has a yellowish tint (left and right side and bottom seem to have less yellowing).

I have a couple questions would greatly appreciate feedback from you experts.

o) Is it possible that a bad cap (or poorly soldered cap) on the PS or logic board would cause the yellow tint issue(still have 9 small caps on the logic board to go). Or is it more likely a problem with the backlight or other issue?

o) If a bad cap could be the problem any tips to narrow things down.

I could try replacing the remaining 9 small caps on the logic board to rule this out but what if one of the replaced ones is bad, cold solder joint, open ...

o) Can the caps be easily destroyed by overheating? Know they are not as sensitive as transistors, but a few got a little hotter than I would have liked.

Any pointers appreciated.

[Troublicious]

Re: Hanns-G HG281D, LCD Monitor no power

Hi,

at first, thank you all for your excellent advice ! I succeeded to bring back to life a HG281D by changing just 2 caps on the video card.
But before this result, i tried to change a lot of caps on power and video card of another HG281D: strange area of red pixels disappeared and i can turn it on instantly. The problem is that i cannot change brightness anymore!
On OSD i can move from 0 to 100, but nothing changes on the screen, it is like the brightness is blocked at 0 ... Someone already saw that ? Any idea on what to do to solve this problem ? I checked continuity with a multimeter and everything seems ok, maybe a cap that i replaced is bad, but which one ?
Thanx in advance for your help,

Greetings from France