Hanns-G HG281D, LCD Monitor no power

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

However, I read through your post a couple times and it seems (correct me if I am wrong) that the power supply board may be OK despite the darker area that I could see on that as well. You clearly point out IMG_3871 and IMG_3872, which is the logic board, am I correct?

Correct.

I now carefully inspected that board and found something that I wanted to share with you. I tried my best with the cam and took image P1010223.JPG.
Is that irregularity on the side of the capacitor something abnormal? Does it indicate any problem at all, potentially, or most definitely?

Can't say for sure. The capacitor hasn't bulged but it definitely looks like there was some heat damage done to it. The black rectangular things you see in that area (U7 and U8) are linear voltage regulators - they tend to generate a lot of heat. Given the reputation of CapXon, it would be a good idea to replace all of them in that area - that is, replace C80, C13, C83, C74, C77, C8, and C14.
As for the rest of the capacitors on the logic/video board, I would say replace those too, but if you're not feeling too comfortable soldering, then you may leave those alone. Particularly, the ones in the lower-left corner of IMG_3871 are likely used by the audio amp (U10) so they are not under a whole lot of stress and may be left alone.

For replacements of CapXon KM, you can use any of the following:
FC, FR, and FM series from Panasonic
PM, PW, and HE series from Nichicon
KY, KZE, LZX, and LXY series from United Chemicon
YXG, and ZL series from Rubycon
(The ones in bold are the closest match on specs)
Most of these are available on Digikey and Mouser.

[heli2reg]

Re: Hanns-G HG281D, LCD Monitor no power

Can't say for sure. The capacitor hasn't bulged but it definitely looks like there was some heat damage done to it. The black rectangular things you see in that area (U7 and U8) are linear voltage regulators - they tend to generate a lot of heat. Given the reputation of CapXon, it would be a good idea to replace all of them in that area - that is, replace C80, C13, C83, C74, C77, C8, and C14.
As for the rest of the capacitors on the logic/video board, I would say replace those too, but if you're not feeling too comfortable soldering, then you may leave those alone. Particularly, the ones in the lower-left corner of IMG_3871 are likely used by the audio amp (U10) so they are not under a whole lot of stress and may be left alone.

For replacements of CapXon KM, you can use any of the following:
FC, FR, and FM series from Panasonic
PM, PW, and HE series from Nichicon
KY, KZE, LZX, and LXY series from United Chemicon
YXG, and ZL series from Rubycon
(The ones in bold are the closest match on specs)
Most of these are available on Digikey and Mouser.

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!

[jetadm123]

Re: Hanns-G HG281D, LCD Monitor no power

I suspect one of the problems you're running into, especially with caps 47uf and smaller, is that some of those caps have their leads at the base bent into a zig-zag pattern. When pushed into the circuit board board, it locks the cap in place prior to the soldering process. And yes, it can be a pain to remove. For the larger caps, you should be able to heat the solder pad while gently pushing on the same side of the cap of the lead you're heating up. Repeat process for the opposite side and keep repeating until the cap pulls free from the board. If you don't feel comfortable doing this, order some de-soldering braid from digikey and use it to soak up the solder from the pads.

As for the small caps under the metal shield, from the looks of your photos, I see only one? You should be able to reach that with pliers, since it's near the edge, without having to remove the shield.

[heli2reg]

Re: Hanns-G HG281D, LCD Monitor no power

I suspect one of the problems you're running into, especially with caps 47uf and smaller, is that some of those caps have their leads at the base bent into a zig-zag pattern.

You confirmed my suspicion. What a pain in the rear fany!

[...]order some de-soldering braid from digikey and use it to soak up the solder from the pads.

Will do - Thanks!

As for the small caps under the metal shield, from the looks of your photos, I see only one? You should be able to reach that with pliers, since it's near the edge, without having to remove the shield.

Good point. I think I will attempt the logic board first and see where that goes. Hopefully not Mount Trashmore. If it fixes the issue, I won't touch the power board.

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

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.

Would that be this person's post?
https://www.badcaps.net/forum/showpo...7&postcount=28
If so, I don't think his problem was resolved.
Also, I re-read through the thread, and it seems that quite a number of people fixed their monitors by replacing capacitors C603, C606, and C707 on the power supply board. This may or may not be the problem of your monitor, but since so many people have had problems with those, I would highly recommend you get replacements for those too. In addition, your power supply board seems to have a lot of heat discoloration near C406 and C701 so get those too.
If you need help choosing replacements, just post what the original capacitors are.

This is how I normally remove caps:
https://www.badcaps.net/forum/showth...8887#post78887
Some boards are indeed tougher than others. My suggestion is to add a little bit of solder on your iron before heating the joint. This will also tell you when your iron is hot enough. If the solder doesn't melt on the tip easily, it's not hot enough.
The other thing is, don't wiggle or apply any force on the cap until you can see the solder on its pads melt.
Solder wick or a desoldering bulb may also be helpful.

I think I will attempt the logic board first and see where that goes.

Sounds good. This will give you a better idea of what the original problem was too.

All in all, purging bad or heat-damaged caps is always good, even if it doesn't fix the problem because at least it eliminates other "potential" problems. Judging by the hotspots on the PSU and video/logic board, this monitors must have really poor ventilation.

[heli2reg]

Re: Hanns-G HG281D, LCD Monitor no power

Would that be this person's post?
https://www.badcaps.net/forum/showpo...7&postcount=28
If so, I don't think his problem was resolved.

True. I have not found a resolution to this particular issue either.

Also, I re-read through the thread, and it seems that quite a number of people fixed their monitors by replacing capacitors C603, C606, and C707 on the power supply board. This may or may not be the problem of your monitor, but since so many people have had problems with those, I would highly recommend you get replacements for those too. In addition, your power supply board seems to have a lot of heat discoloration near C406 and C701 so get those too.

Good idea. I might as well get them all in one shipment, but test them out by sections hopefully helping isolating the issue and potentially helping somebody down the road pinpointing the issue a bit faster.

If you need help choosing replacements, just post what the original capacitors are.

I went online @ Digi-Key and dang, this is a bit over my head. I see there are many additional parameters besids V, uF, with, hight. A couple I think I found, but some others (like the 470uF) I cannot find. Your help on that would be greatly appreciated!!!

Logic board:
CapXon, 16V, 10μF, 105°C, P733, 4.2mm dia, 5.75mm h, 1.5mm lead spacing, 6mm dia surface space, 2mm spaced holes
CapXon KM, 16V, 100μF, 105°C, P729, 5.2mm d, 11.5mm h, 2mm ls, 7mm sp, 2mm sh
CapXon KM, 16V, 100μF, 105°C, P735, 8.2mm d, 13mm h, 2.5mm ls, 8.2mm sp, 2.5mm sh

PSU board:
C603: Ltec (?) TK, 35V, 22μF, 105°C, 7616D, 5.15mm d, ~11mm h, 5.5mm ls, 5.5mm sp, 5.5mm sh
C606: United Chemicon (?) VT (can't really say w/o removing it from board)
C707: Ltec (?) TK, 35V, 22μF, 105°C, 7616D, 5.15mm d, ~11mm h, 5.5mm ls, 5.5mm sp, 5.5mm sh

C406: United Chemicon KY, 50V, 10μF, (M)105°C
C701: United Chemicon (can't really say w/o removing it from board)

Also, one Q: What's the white plastic stuff added to the sides of the capacitors, sometimes bonding them together?

Then, I will also need solder wick, desoldering braid/bulb, and any other good items you can recommend.

This is how I normally remove caps:
https://www.badcaps.net/forum/showth...8887#post78887
Some boards are indeed tougher than others. My suggestion is to add a little bit of solder on your iron before heating the joint. This will also tell you when your iron is hot enough. If the solder doesn't melt on the tip easily, it's not hot enough.

Thank's for the advise. I actually added some solder to the joint. I figured more body would be able to provide more heat and in fact, this was the first cap I was able to remove in one piece. Removing the excess solder is much easier than trying to deal with a partial left in place lead that's flush with the PCB.

The other thing is, don't wiggle or apply any force on the cap until you can see the solder on its pads melt.
Solder wick or a desoldering bulb may also be helpful.

Items are on the shopping list for Digi-Key or whoever can provide the caps I need.

Sounds good. This will give you a better idea of what the original problem was too.

All in all, purging bad or heat-damaged caps is always good, even if it doesn't fix the problem because at least it eliminates other "potential" problems. Judging by the hotspots on the PSU and video/logic board, this monitors must have really poor ventilation.

[retiredcaps]

Re: Hanns-G HG281D, LCD Monitor no power

I went online @ Digi-Key and dang, this is a bit over my head.

Also, one Q: What's the white plastic stuff added to the sides of the capacitors, sometimes bonding them together?

1) PlainBill wrote a procedure on how to choose Panasonic FR, FM, and FC caps at

https://www.badcaps.net/forum/showpo...33&postcount=2

2) If you want a more streamlined approached, goto digikey.com. Try this.

a) Check the "in stock" box.
b) In the search field type in "470uF 25V FR". If it comes back successful, check the diameter and height to make sure they fit. Repeat for all other caps.
c) If the FR search was unsuccessful, try "470uF 25V FM". If that also fails, try "470uF 25V FC".

Basically your first choice is FR, them FM, and finally FC.

3) The white stuff is glue to hold the components in place during the manufacturing process. You can remove the glue (especiallly if it turned brown).

[heli2reg]

Re: Hanns-G HG281D, LCD Monitor no power

1) PlainBill wrote a procedure on how to choose Panasonic FR, FM, and FC caps at

https://www.badcaps.net/forum/showpo...33&postcount=2

I have followed these instructions and think to have gotten quite comfortable except that in some cases so many results pull up that I don't know the difference from one to another, e.g. what does the "Ripple Current" rating have to say, or the "Impedance" ... that's where I get lost. I kinda know what it means in theory, but don't know which is better or worse.

I just realized that I made one obvious listing error. The 3rd line on the logic board should be:

CapXon KM, 16V, 470μF, 105°C, P735, 8.2mm d, 13mm h, 2.5mm ls, 8.2mm sp, 2.5mm sh

And with these specs - trying 25V as well - I could not find any matches.

[...]
Basically your first choice is FR, them FM, and finally FC.

Does that apply for Panasonic, Nichicon, and United Chemi-Con? In which order should I select the brand?

[retiredcaps]

Re: Hanns-G HG281D, LCD Monitor no power

e.g. what does the "Ripple Current" rating have to say, or the "Impedance" ... that's where I get lost.

PCBONEZ explains it at

https://www.badcaps.net/forum/showpo...30&postcount=7

CapXon KM, 16V, 470μF, 105°C, P735, 8.2mm d, 13mm h, 2.5mm ls, 8.2mm sp, 2.5mm sh

Use Panasonic FR

http://search.digikey.com/scripts/Dk...name=P14394-ND

Does that apply for Panasonic, Nichicon, and United Chemi-Con? In which order should I select the brand?

A list of good caps is at

https://www.badcaps.net/forum/showthread.php?t=2280

[heli2reg]

Re: Hanns-G HG281D, LCD Monitor no power

PCBONEZ explains it at
https://www.badcaps.net/forum/showpo...30&postcount=7

Use Panasonic FR
[...]

So, if I may ask, what would be the proper replacement for
CapXon, 16V, 10μF, 105°C, P733, 4.2mm dia, 5.75mm h, 1.5mm lead spacing, 6mm dia surface space, 2mm spaced holes?

P11212-ND or P14482-ND or is there even a better one?

I assume P11212-ND, but your input will greatly help me making the right choices down the road. Thank you!

[heli2reg]

Re: Hanns-G HG281D, LCD Monitor no power

So, if I may ask, what would be the proper replacement for
CapXon, 16V, 10μF, 105°C, P733, 4.2mm dia, 5.75mm h, 1.5mm lead spacing, 6mm dia surface space, 2mm spaced holes?

P11212-ND or P14482-ND or is there even a better one?
[...]

I think I answered my question with 493-1767-ND - correct?

Thanks again for all your help and assistance!

[retiredcaps]

Re: Hanns-G HG281D, LCD Monitor no power

I think I answered my question with 493-1767-ND - correct?

Either the Nichicon PW (493-1767-ND) or Panasonic FC (P11212-ND) will work fine.

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

CapXon KM, 16V, 470μF, 105°C, P735, 8.2mm d, 13mm h, 2.5mm ls, 8.2mm sp, 2.5mm sh

And with these specs - trying 25V as well - I could not find any matches.

Use Panasonic FR

Well, in this case, it appears that the 16v, 470uF CapXon KM are near the audio amp, so it's probably better if they get replaced with something closer to their specification. Panasonic FR is a few grades better than CapXon KM, but Panasonic FC or Nichicon PW is a much better match.
......
It appears that the Ltec TK series are also general purpose caps like CapXon KM. So, the list of suitable replacements I posted for CapXon KM is also applicable to the Ltec TK caps.

[heli2reg]

Re: Hanns-G HG281D, LCD Monitor no power

Status update:
I went above and beyond and decided that I may want to make fixing hardware my hobby as time permits. I purchased items >$600 with Digi-Key - a multi-meter with capacitance testing capability and some more bells and whistles (knowing it would not solve hardware issues, but maybe make it more motivating working with it), a work center with vise (this really makes all the difference when soldering!), and basics (!), such as soldering braid, flux and tin.

So, on the intermittent power-on monitor issue: I got the fix in the wrong direction: Not intermittent any longer. It now remains off. I assume this is bad news but just wondering if that's necessarily the case, or if in fact something may have been fixed, but there may some other issue colliding with it. For now I guess I made things worse and I believe to know the issue to be the logic board. It may be the one whole where I simply couldn't get the cap lead removed from. My force might have been to brutal on the board. Anyhow, now I got a few questions on that:

First, on that logic board: Do I understand correctly that there are two types of PCBs? On the PSU board, one side has no traces at all but components only, the traces are all on one side. On the logic board, however, it seems that the entire board beneath the surface has a conductive layer where the traces are made by a de-facto frame, which is not conductive, around the surface or trace that is supposed to be connected. True? Not true? - I really should get into the weeds and start on a practice board if I want to fix this monitor rather than using it for practice and breaking more than fixing.

Second: I know an eyelet repair would probably be in order but can I get away with fixing this problem once with solder only? Setting the trace free on both sides on the logic board and connecting the solder with the leads of the capacitor? I wonder what's the easier surgery? That, or going through an eyelet repair procedure?

[Scenic]

Re: Hanns-G HG281D, LCD Monitor no power

First, on that logic board: Do I understand correctly that there are two types of PCBs? On the PSU board, one side has no traces at all but components only, the traces are all on one side. On the logic board, however, it seems that the entire board beneath the surface has a conductive layer where the traces are made by a de-facto frame, which is not conductive, around the surface or trace that is supposed to be connected. True? Not true? - I really should get into the weeds and start on a practice board if I want to fix this monitor rather than using it for practice and breaking more than fixing.

yep. the powersupplies are usually single-layer, the logic boards are multi-layer (just like computer motherboards)

[PlainBill]

Re: Hanns-G HG281D, LCD Monitor no power

The proper repair of a damaged feed-thru involves inserting an eyelet. Soldering top and bottom, or better yet, running a fine gauge wire through the hole alongside the lead and soldering it top and bottom works quite well. Just don't expect it to pass a NASA inspection.

In may ways I prefer working on 'hard' failures rather than intermittent problems. With intermittent problems, unless you find a verifiable cause (bad solder joint), you can't be sure the problem won't come back.

PlainBill

[retiredcaps]

Re: Hanns-G HG281D, LCD Monitor no power

a multi-meter with capacitance testing capability and some more bells and whistles

Why multimeter did you get if you don't mind sharing?

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

So, on the intermittent power-on monitor issue: I got the fix in the wrong direction: Not intermittent any longer. It now remains off.

Question - did you change any caps on the PSU? (more particularly, any small caps)?
The reason I'm asking is because Steven_C ran into a similar issue where his PSU would no longer turn on because he found that he accidentally ripped a trace on the PSU board. His thread can be found in the link below. If you have not changed any caps on the PSU, then disregard my question:
https://www.badcaps.net/forum/showth...358#post162358

As for the logic board - as long as you haven't lifted any traces or accidentally chipped any SMD components, it should be okay. Check the voltages on the various pins of U7 and U8 with respect to ground. Let me know what they are. If you get 0V for all of them, check that the PSU is outputting the proper voltages - that is, first measure 5vsb without turning on the monitor. If present, then turn on the monitor (or, well, try to) and check 5v, 12v, and 24v rails.

[julealgon]

Re: Hanns-G HG281D, LCD Monitor no power

Hi there all.

I found this forum today when I was searching on possible problems for this same monitor. I bought it maybe a year/year and half ago, and today it, out of the blue, shut down on me. I was browsing the internet for other stuff when it simply powered off. I tried switching cables and things like that to no avail, the monitor acts like no power is present (no blue/orange light at all).

My initial question is if it is completely safe to open it. I'm not on the same knowledge level you guys are with this kind of equipment. I barely know what a capacitor is, and I'm afraid to destroy the whole thing for good.

What I was reading is that repair costs for these monitors are very high because they tend to switch the whole module. I'm willing to learn how this thing works and trace the problem like some of you did. I'm a computer science student (at the sixth semester at the moment) so I think that with enough effort and patience I could probably learn how to repair this.

I have no tools for this though, and it seems some of them are expensive (I've seen someone comment here that an equipment to measure one of the capacitor parameters - ESR or something like that - to cost between 50 and 300 dollars).

The fact that I live in Brazil and actually imported this monitor from eBay complicates things a whole lot. I'm not even sure there is anyone here that ever heard of Hanns-G (though it seems most of these monitors work similarly).

Anyways, I'm sorry for interfering in the thread like this (this is my first post actually), but my problem seems to be exactly the same, and I felt hopeful for a moment.

Your forum is quite nice I must say.

Any tips would be extremely appreciated.
Regards,
Juliano Goncalves

[retiredcaps]

Re: Hanns-G HG281D, LCD Monitor no power

the monitor acts like no power is present (no blue/orange light at all).

Rather than repeat myself, see this post on how to post pictures

https://www.badcaps.net/forum/showpo...76&postcount=2

My initial question is if it is completely safe to open it.

Unplug the monitor and let it sit for about 1 hour. Then open it.

I'm not on the same knowledge level you guys are with this kind of equipment. I barely know what a capacitor is, and I'm afraid to destroy the whole thing for good.

You will need a multimeter and a soldering iron at minimum.