Hanns-G HG281D, LCD Monitor no power

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

Since your symptoms are worse, and it won't even power on at all now; we could conclude it has something to do with your cap replacement repair.

(1) Make sure the caps were put in the right way according to their polarity.

(2) Look for lifted pads on the solder joints. With that board I remember the manufacturer bent the legs all the way over onto the pads. Unless all the solder is removed, and the legs bent up; it's very easy with that board to pull a pad. I've repaired a few of those AFTER somebody attempted a repair, and every time it was a lifted pad that later caused the problem. When that happens you need to bend the leg of the cap, and connect it to where the the thin copper trace connected to from the cap leg's lifted pad.

Hope that helps.

[james2323]

Re: Hanns-G HG281D, LCD Monitor no power

When you hook the power supply to an AC voltage only one output will be 'live' - the 5 volt standby (+5VSB) pin on the 11 pin connector at the end of the supply. If that shows 5 volts, unplug the power cord, hook up the signal card, and check the PSON pin and recheck the +5VSB pin on the same connector. Given the symptoms, I'd expect PSON to be low.

PlainBill

Through reading this very through and informative thread, i have replaced many of the Caps on my HG281D Power supply board (ive replaced about 18 caps on the PS board, the ones most commonly suggested/listed here to be replaced).

When i try to test the +5VSB as described above by PlainBill, (with only the AC main plugged to the power supply board, nothing else) all 11 pins read the same, they all constantly fluctuate between ~ -.13 v dc and ~ +.30v dc (to verify, the way I take this reading: i set my multi-meter to 20v DC and touch the black lead to the ground point coming from the AC IN on the monitor frame (that short green cable that is screwed to the monitor's metal frame) , and this is the reading i get.)

The symptoms that lead me to even open up this monitor (and replace the caps) were that it would flash / power itself off after about 1-60 seconds (i could press the power button several times, sometimes, and get it to repeat the 1-60s) - After i replaced the caps and put the monitor back together, it wont even power on (nor illuminate the blue/orange light)

Anyone have any info as to where i should look for what ive done wrong when i replaced the caps to get this strange DCv fluctuation on the 11 pins (where i was hoping to see the 5vDC so i could the move on to taking readings on the Signal board).

thanks

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

@momaka, I am gonna start the recap of this monitor, i want to change all of the capacitors.
Since i do not have an ESR meter, can you help me to get a full list of the capacitors names? With all the boards on this monitor?

For the list of capacitors regarding the PSM217-404 power board, see this:
https://www.badcaps.net/forum/attach...2&d=1341463821

Then, use any of the capacitors from the following list:
https://www.badcaps.net/forum/showpo...22&postcount=9

Also get the two capacitors on the LCD logic board, like mentioned here:
https://www.badcaps.net/forum/showpo...&postcount=629

[N_R_G]

Re: Hanns-G HG281D, LCD Monitor no power

Which caps should I replace on the power supply board?

Most of times (99%) just replace the three marked in red... Other times It could be necessary replace also the caps marked in blue...

https://www.badcaps.net/forum/attach...8&d=1435812326

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

OK, you did use PANASONIC FR series.
I would do the recap of the whole power supply board, you may not need to do the main filter cap in the primary side.

[SturmGhost]

Re: Hanns-G HG281D, LCD Monitor no power

Not sure but I think I used:

"RAD FR 100/50 Elko radial, 105°C, low ESR, RM 3,5mm" Brand: Panasonic

Which caps should I replace on the power supply board?

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Did you use use good quality caps for the C80, 83?
How about the caps in the power supply board?

[SturmGhost]

Re: Hanns-G HG281D, LCD Monitor no power

I think I have an issue with my monitor (HG281D).

Sometimes (happens more often when the monitors runs a longer time) when I scroll down a website some horizontal "artifacts"/distortion appears at 4/5 height of the panel height.
It can't be a computer problem because I build a new one and the problem is still there. A year ago I changed C80 and C83 because of weird on/off behavior of my monitor (it fixed the on/off behavior).

Does anybody have an idea how to fix my monitor?

[tito_hydra]

Re: Hanns-G HG281D, LCD Monitor no power

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)

@momaka, I am gonna start the recap of this monitor, i want to change all of the capacitors.
Since i do not have an ESR meter, can you help me to get a full list of the capacitors names? With all the boards on this monitor?
Sorry for bother you, also sorry my bad english.

[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)

[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

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

@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

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

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...)

[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...

[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

[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.

[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?

[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)