Hanns-G HG281D, LCD Monitor no power

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

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

[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.

[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!

[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.

[kadi144]

Re: Hanns-G HG281D, LCD Monitor no power

many thanks for all

[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

[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

@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

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

thank's momaka, again...

My father has a soldering iron gun with "arc tip", and on it, it's writed 100w

I tried it on my old motherboard to test if I was able to desolder the capacitors... without any results again...

Do you think that old mobo are not soldered with the material, I don't know his name in english, ( "tin" ?), usually used in the other boards?!?

Or maybe I've used two soldering iron that are not good enough/broken?

I'm very frustrated about this... I seen video where people desolder very easily while with my pc mobo It's impossible for me desolder only one capacitor... I have also a desoldering pump but it didn't help me...

I read many not skilled people who adjusted their monitor easily, so the problem is mine or of my old pc motherboard?!?

This 100W soldering iron gun is not adapt for the work? (so before buy another soldering iron, I want to be sure don't spend uselessy others money)

[sean0118]

Re: Hanns-G HG281D, LCD Monitor no power

thank's momaka, again...
...
Do you think that old mobo are not soldered with the material, I don't know his
name in english, ( "tin" ?), usually used in the other boards?!?

Or maybe I've used two soldering iron that are not good enough/broken?
...

The problem is that motherboards have many different layers (including internal layers). There is so much copper that the motherboard will act as a heatsink and suck all the heat out of your soldering iron tip.

You would need a more powerful iron or a larger tip if they are replaceable on your iron. The larger soldering tips have a higher thermal mass so they will not cool down as easily.

You also need to tin the tip of the iron with solder first so that there is good heat transfer between the iron and the board.

I'm not sure what the problem is with the "arc tip" iron, is it the type that runs a high current through the solder to melt it?

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

I remove those caps by using flux and ADD more regular solder to the pads using 50W wide tip soldering Iron while moving the tip back and forth between the two pads and pulling on the cap and thne use stainless dental probe to clear the holes while heating up the pads after the caps are removed.

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

My father has a soldering iron gun with "arc tip", and on it, it's writed 100w

I tried it on my old motherboard to test if I was able to desolder the capacitors... without any results again...

I have one of those soldering iron guns as well. They are no good for motherboards either. Mine is rated for 60 Watts. It heats up very quickly to full temperature. But the "arc" tip is simply too thin to "store" any heat, so it can't heat the motherboard joints properly to melt the solder. I've already tried it.

This 100W soldering iron gun is not adapt for the work? (so before buy another soldering iron, I want to be sure don't spend uselessy others money)

Yes, quite possibly.
If you can, please post a picture of it here so we can see. That way we can tell you before buying another soldering iron.

Do you think that old mobo are not soldered with the material, I don't know his name in english, ( "tin" ?), usually used in the other boards?!?

The material is called solder. But "Tin" is often one of the elements that makes up that material. For standard 60/40 solder, there is 60 parts of Tin (Sn) to 40 parts Lead (Pb).

Or maybe I've used two soldering iron that are not good enough/broken?

Not broken. Probably just not good enough.

Having the right tool for the job is always helpful. I used to struggle with my 30 Watt soldering iron for a long time until I started using flux. The flux made everything a little bit easier. But I still couldn't work on PC motherboards. Then I tried a 60 Watt soldering iron, and that made things even easier. Then a friend gave me a proper 75 Watt soldering station with temperature regulation, and I have not found anything I can't desolder with it.

I'm very frustrated about this... I seen video where people desolder very easily while with my pc mobo It's impossible for me desolder only one capacitor...

Don't worry, you'll get better at it quickly. Again, having a good iron will help you a lot.

I have also a desoldering pump but it didn't help me...

Desoldering pump is really only good for removing ICs or small to medium components on single-sided boards... like on old CRT TVs.

For motherboards, you don't need a desolder pump. This is the method I use for removing capacitors:
https://www.badcaps.net/forum/showpo...7&postcount=23

[N_R_G]

Re: Hanns-G HG281D, LCD Monitor no power

I have one of those soldering iron guns as well. They are no good for motherboards either. Mine is rated for 60 Watts. It heats up very quickly to full temperature. But the "arc" tip is simply too thin to "store" any heat, so it can't heat the motherboard joints properly to melt the solder. I've already tried it.
...

For motherboards, you don't need a desolder pump. This is the method I use for removing capacitors:
https://www.badcaps.net/forum/showpo...7&postcount=23

I tried your method, but without any results... So do you think with 100w soldering iron gun it will impossibile also with Power supply of the HG281D without damage anything (or only for PC mobo)?

Sorry but I can't upload any photos at the moment, my old cell phone wan't connect via bluetooth with my pc
However it something similar to this:



there is written:

3S 100W
12s/48s



@budm & @sean0118: thank's for your answers I also take these in consideration...

[N_R_G]

Re: Hanns-G HG281D, LCD Monitor no power

Regarding this

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

Is there one of those capacitors that It's specifically responsable to give the start-up eletricity to the monitor?

Seen my low skill with this type of work, I would like to change only the responsable of the power failure when the monitor isn't heated by the hair drayer...

(waiting for a friend, He should lend me his Soldering iron station...)

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

I tried your method, but without any results... So do you think with 100w soldering iron gun it will impossibile also with Power supply of the HG281D without damage anything (or only for PC mobo)?

That 100 W soldering gun may be okay for the HG281D power supply. But even your 25 W iron will work for that.

PC motherboards are the toughest, and that soldering gun is not suitable for them. Neither is the 25 W iron.

Sorry but I can't upload any photos at the moment, my old cell phone wan't connect via bluetooth with my pc
However it something similar to this:
https://images-na.ssl-images-amazon....1TJC2nZKGL.jpg

Yeah, that's almost the same as the 60 Watt Weller gun I have. In my experience, those guns are not good for modern circuit boards (especially PC motherboards, which have very thick copper planes and pads). But I will dig it from my closet tomorrow if I can and try it again.

Is there one of those capacitors that It's specifically responsable to give the start-up eletricity to the monitor?

Pretty much all of the small caps circled in *blue* and *red* in this picture:
https://www.badcaps.net/forum/attach...2&d=1399761254

Seen my low skill with this type of work, I would like to change only the responsable of the power failure when the monitor isn't heated by the hair drayer...

Right.
Unfortunately, the HG281D is one of those monitors that has several problems related to capacitors, so that's why there are so many caps to replace. In particular, if you don't change C80 and C83 on the logic board, you can get strange monitor behavior.

[N_R_G]

Re: Hanns-G HG281D, LCD Monitor no power

@momaka:

Thank's again for yours so goods specifications answers...

Pretty much all of the small caps circled in *blue* and *red* in this picture:
https://www.badcaps.net/forum/attach...2&d=1399761254

Yes I readed the entire thread before post my first message, I only hoped that only one of these caps could be the responsable of the my power issue...

Right.
Unfortunately, the HG281D is one of those monitors that has several problems related to capacitors, so that's why there are so many caps to replace. In particular, if you don't change C80 and C83 on the logic board, you can get strange monitor behavior.

I thought that the two logic board capacitors were to change only in case I had flickering problems or other image problems... I readed this in the old previous posts of this Threads... So I'm wrong about that?
My HG281D works perfectly once it's switched on (no flickering, no bad colors or other imagine's issues)

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

Yes I readed the entire thread before post my first message, I only hoped that only one of these caps could be the responsable of the my power issue...

If I remember correctly, the power supply of this monitor had several different "no power" failure modes, and each was caused by one of these capacitors. So that's why we suggest to replace all of these small capacitors.

Don't worry though. These smaller capacitors on the power supply should be much easier to remove than the caps on a PC motherboard.

I thought that the two logic board capacitors were to change only in case I had flickering problems or other image problems...

Correct.

But it's not a matter IF those capacitors will fail, but a matter of WHEN. I've seen people in this thread revive their monitor from "no power" problem only to have the monitor working for a few weeks and then develop image problems (which sometimes includes the monitor not detecting when a signal is sent to it at all).

So if you get a chance, definitely replace C80 and C83 on the logic board too.

Also, I checked my 60 W soldering gun (like the one you show above). It was actually a 75 Watt gun (made by Weller, model Standard 7200). I couldn't get it to even melt lead-free solder from my solder spool. So definitely don't use it. I think even your 25 Watt soldering iron will be better than that. I have a 30 Watt Radio Shack iron, and I can use it for most power supplies that use a single layer board with small to medium traces.

See if there are any local TV/electronics repair shops around you and ask if they have any junk computer power supplies. Practice soldering and desoldering on those with your 25 Watt iron (or your friend's borrowed iron). When you get better, you can attempt to work on your monitor.

[N_R_G]

Re: Hanns-G HG281D, LCD Monitor no power

If I remember correctly, the power supply of this monitor had several different "no power" failure modes, and each was caused by one of these capacitors. So that's why we suggest to replace all of these small capacitors.

Don't worry though. These smaller capacitors on the power supply should be much easier to remove than the caps on a PC motherboard.


Correct.

But it's not a matter IF those capacitors will fail, but a matter of WHEN. I've seen people in this thread revive their monitor from "no power" problem only to have the monitor working for a few weeks and then develop image problems (which sometimes includes the monitor not detecting when a signal is sent to it at all).

So if you get a chance, definitely replace C80 and C83 on the logic board too.

Also, I checked my 60 W soldering gun (like the one you show above). It was actually a 75 Watt gun (made by Weller, model Standard 7200). I couldn't get it to even melt lead-free solder from my solder spool. So definitely don't use it. I think even your 25 Watt soldering iron will be better than that. I have a 30 Watt Radio Shack iron, and I can use it for most power supplies that use a single layer board with small to medium traces.

See if there are any local TV/electronics repair shops around you and ask if they have any junk computer power supplies. Practice soldering and desoldering on those with your 25 Watt iron (or your friend's borrowed iron). When you get better, you can attempt to work on your monitor.

ok,

I will post again here when I will get the work, thank's for all...






PS: Does someone know a valid site that it sends also to Italy (with low send costs) and where I can retrive all the HIGH QUALITY/LOW RES Capacitors (as Panasonic FM/FR 105°) I need?

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

PS: Does someone know a valid site that it sends also to Italy (with low send costs) and where I can retrive all the HIGH QUALITY/LOW RES Capacitors (as Panasonic FM/FR 105°) I need?

There websites might have something for you:

badcaps.net store
https://www.badcaps.net/index.php?pageid=master_list
(international shipping is stated as $9.50

RS components:
http://it.rs-online.com/web/

Farnell/element14
http://www.farnell.com/

or you can also contact member behemot on this forum (he's based in CZ, Europe)