Hanns G HG281D 2 second black screen and parts help

[nuhhht]

Hey guys,

I have a Hanns G HG281D 28" 1920x1200 5ms monitor that has recently started to show symptoms of a bad inverter ie: the screen would show grey lines of brightness (flickering kind of) the icons on the desktop would look as if they were being shaken. Also, randomly the screen would turn off but the power led light would stay on.

So I pulled the monitor apart and looked over power board, inverter, and lcd controller for bad capacitor but didn't find anything bulging or leaking. I ordered a replacement inverter from ebay but the symptoms were the same. The likely hood that I have two bad inverters are slim i would think but you never know.

Onto recapping the inverter. All 4 of the caps have T0735 105 PET on them but that's is it as far as markings. Do you guys have any secrets of telling what capacitor I need to order. I will be supplying pictures shortly detailing what exactly I'm talking about. I will also pull the power supply to get detailed pictures just in case you guys see something I may have missed. Thank you!

Something to note is that the screen shaking sometimes will settle out and the monitor works fine with no distorted shaking of any kind. When looking at the screen really closely while it's powered up I can see like faint flickering of white lines.

Sorry for the crappy pictures I only have my iphone. Will get better camera soon.

[PlainBill]

Re: Hanns G HG281D 2 second black screen and parts help

Hey guys,

I have a Hanns G HG281D 28" 1920x1200 5ms monitor that has recently started to show symptoms of a bad inverter ie: the screen would show grey lines of brightness (flickering kind of) the icons on the desktop would look as if they were being shaken. Also, randomly the screen would turn off but the power led light would stay on.

So I pulled the monitor apart and looked over power board, inverter, and lcd controller for bad capacitor but didn't find anything bulging or leaking. I ordered a replacement inverter from ebay but the symptoms were the same. The likely hood that I have two bad inverters are slim i would think but you never know.

Onto recapping the inverter. All 4 of the caps have T0735 105 PET on them but that's is it as far as markings. Do you guys have any secrets of telling what capacitor I need to order. I will be supplying pictures shortly detailing what exactly I'm talking about. I will also pull the power supply to get detailed pictures just in case you guys see something I may have missed. Thank you!

Something to note is that the screen shaking sometimes will settle out and the monitor works fine with no distorted shaking of any kind. When looking at the screen really closely while it's powered up I can see like faint flickering of white lines.

Sorry for the crappy pictures I only have my iphone. Will get better camera soon.

Those symptoms would indicate a problem either with the main power supply or the logic card. In particular, a bad inverter would not cause the screen shaking you mention.

PlainBill

[nuhhht]

Re: Hanns G HG281D 2 second black screen and parts help

Thanks Bill. I will tear apart the power supply and put up some pictures.

[nuhhht]

Re: Hanns G HG281D 2 second black screen and parts help

Ok, I pulled the power supply out and found a semi bulging 1000uF 35v cap that I replaced. Fired the screen back up and no change except that the problems only happen during the first few minutes of starting the monitor. After awhile everything goes back to normal and the screen is like new.

So what I'm thinking of doing is replacing majority of the caps on the power supply board for a start. I have never bought caps before so your input is very welcomed.

What I need: All are rated 105 degrees radials.
470uF 35v
22uF 35v
22uF 35v
22uF 400v
10uF 50v
1000uF 10v
470uF 25v
470uF 10v
1000uF 25v
1000uF 25v
1000uF 35v
2.2uF 50v

I also noticed a few spots on the bottom of the circuit board of burnt type spots but nothing major that would indicate a short.

Once again, I will update nice pictures soon!

[retiredcaps]

Re: Hanns G HG281D 2 second black screen and parts help

Having gone through this exercise in another thread, what are the diameter and height measurements of the existing caps? From your pic some of the caps are very close to each other.

Also, it looks like the replacement 1000uF 35V is a Radio Shack cap? While it may work, it is not optimal for this type of application. So you should replace that one as well.

PS. List your location so we can determine the nearest supplier in your country. I'm assuming USA from the Radio Shack cap?

Ok, I pulled the power supply out and found a semi bulging 1000uF 35v cap that I replaced. Fired the screen back up and no change except that the problems only happen during the first few minutes of starting the monitor. After awhile everything goes back to normal and the screen is like new.

So what I'm thinking of doing is replacing majority of the caps on the power supply board for a start. I have never bought caps before so your input is very welcomed.

What I need: All are rated 105 degrees radials.
470uF 35v
22uF 35v
22uF 35v
22uF 400v
10uF 50v
1000uF 10v
470uF 25v
470uF 10v
1000uF 25v
1000uF 25v
1000uF 35v
2.2uF 50v

I also noticed a few spots on the bottom of the circuit board of burnt type spots but nothing major that would indicate a short.

Once again, I will update nice pictures soon!

[nuhhht]

Re: Hanns G HG281D 2 second black screen and parts help

Yes I'm in the USA and purchased this temp cap from there.

I will get measurements but majority of the caps were the same dimensions as the 1000uF cap from radioshack.

Something else to note is that the monitor seems to be getting extremely hot which would indicate why the bottom of the power supply board looks burnt a bit.

[retiredcaps]

Re: Hanns G HG281D 2 second black screen and parts help

Most monitors I find in public areas (like library, stores) have all their settings set on "torch" mode. Torch mode is 90+/100.

If your brightness level is 90/100 (100/100 being brighest), the monitor is going to draw more power and produce more heat. Most of my monitors at home are 50/100 or 30/100 on the brightness scale depending on the location.

Heat will also cause the caps to die earlier too. I think the I read that every 10C increase in temp halves the life of the cap. Or every 10C decrease in temp doubles the life of the cap.

PS. Post 100 for me!

Something else to note is that the monitor seems to be getting extremely hot which would indicate why the bottom of the power supply board looks burnt a bit.

[PlainBill]

Re: Hanns G HG281D 2 second black screen and parts help

Yes I'm in the USA and purchased this temp cap from there.

I will get measurements but majority of the caps were the same dimensions as the 1000uF cap from radioshack.

Something else to note is that the monitor seems to be getting extremely hot which would indicate why the bottom of the power supply board looks burnt a bit.

As the ESR of a cap rises, the cap generates more heat, which accelerates the deterioration of the cap. Also, ventilation is often not given proper consideration in the design of a monitor, so they run hotter than necessary.

Many caps are available in different form factors - normal, long and thin, and short and stout. When selecting caps it is important to know the maximum height available, and also the diameter of caps in tight spots. I've defaced your picture, placing a red dot on a number of caps that are in tight quarters.

ALSO, there is a particularly nasty failure we encounter from time to time. Small (<100uF) caps can fail with no visible sign. This can cause problems, particularly when a cap in the start-up circuit fails. On the same theory that a lost nail can result in a lost kingdom, I recommend replacing these also. I've tagged them with a green dot.

The 22uF, 400 volt cap is probably for the standby power supply, and is unlikely to be a problem. Your call if you want to go to the trouble of replacing that.

In the FAQ are a couple of threads explaining which caps to buy and where to buy them. I personally recommend Digikey because of their good selection of caps; I'm partial to Panasonic FM and FC series. Also, they offer a USP First Class Mail shipping option, which will get an order like this into your hands in two days for under $3.00.

And this thread will give you a start selecting the appropriate caps.

PlainBill

[PlainBill]

Re: Hanns G HG281D 2 second black screen and parts help

Most monitors I find in public areas (like library, stores) have all their settings set on "torch" mode. Torch mode is 90+/100.

If your brightness level is 90/100 (100/100 being brighest), the monitor is going to draw more power and produce more heat. Most of my monitors at home are 50/100 or 30/100 on the brightness scale depending on the location.

Heat will also cause the caps to die earlier too. I think the I read that every 10C increase in temp halves the life of the cap. Or every 10C decrease in temp doubles the life of the cap.

PS. Post 100 for me!

Yes!!! Now you're a contributing member!!! Contributing member, you want to try your had at selecting these caps, should I do it, or should we let nuhhht go it alone?

PlainBill

[nuhhht]

Re: Hanns G HG281D 2 second black screen and parts help

Let me tackle the selection of caps on my own and will report back with what I came up with

The small caps I included in the list above.

[retiredcaps]

Re: Hanns G HG281D 2 second black screen and parts help

I spy with my two little eyes, 2 smaller caps underneath the heat shield just below the big main filter cap (bottom left hand corner). Make sure to get those as well if you are going to recap everything.

I'll help verify once you get the measurements! Also, you may want to order a spare of each cap if $$$ permits.

Let me tackle the selection of caps on my own and will report back with what I came up with

The small caps I included in the list above.

[nuhhht]

Re: Hanns G HG281D 2 second black screen and parts help

Yes the problem is they used adhesive for one of the components that attaches to the heat shield. Taking that apart will be difficult and I'm not sure what that component may be.

[nuhhht]

Re: Hanns G HG281D 2 second black screen and parts help

Here is what I came up with guys. Most are Panasonic FM series. Any critique is highly appreciated. Thanks!

1 2 P12415-nd Cap 470uf 35v Elect Fm Radial 0 0.61000 $1.22
2 4 P11230-nd Cap 22uf 35v Elect Fc Radial 0 0.33000 $1.32
3 2 P11250-nd Cap 10uf 50v Elect Fc Radial 0 0.28000 $0.56
4 2 P10224-nd Cap 1000uf 10v Elect Fc Radial 0 0.52000 $1.04
5 2 P10274-nd Cap 470uf 25v Elect Fc Radial 0 0.52000 $1.04
6 2 493-1024-nd Cap 470uf 10v Elect Vr Radial 0 0.28000 $0.56
7 4 P10278-nd Cap 1000uf 25v Elect Fc Radial 0 0.85000 $3.40
8 2 P12405-nd Cap 1000uf 35v Elect Fm Radial 0 0.97000 $1.94
9 2 P10313-nd Cap 2.2uf 50v Elect Fc Radial 0 0.26000 $0.52
10 2 493-1449-nd Cap 22uf 400v Elect Vz Radial 0 0.98000 $1.96

[PlainBill]

Re: Hanns G HG281D 2 second black screen and parts help

Here is what I came up with guys. Most are Panasonic FM series. Any critique is highly appreciated. Thanks!

1 2 P12415-nd Cap 470uf 35v Elect Fm Radial 0 0.61000 $1.22
2 4 P11230-nd Cap 22uf 35v Elect Fc Radial 0 0.33000 $1.32
3 2 P11250-nd Cap 10uf 50v Elect Fc Radial 0 0.28000 $0.56
4 2 P10224-nd Cap 1000uf 10v Elect Fc Radial 0 0.52000 $1.04
5 2 P10274-nd Cap 470uf 25v Elect Fc Radial 0 0.52000 $1.04
6 2 493-1024-nd Cap 470uf 10v Elect Vr Radial 0 0.28000 $0.56
7 4 P10278-nd Cap 1000uf 25v Elect Fc Radial 0 0.85000 $3.40
8 2 P12405-nd Cap 1000uf 35v Elect Fm Radial 0 0.97000 $1.94
9 2 P10313-nd Cap 2.2uf 50v Elect Fc Radial 0 0.26000 $0.52
10 2 493-1449-nd Cap 22uf 400v Elect Vz Radial 0 0.98000 $1.96

Depending on the location in the circuit, I would substitute 471uF 10V FC Series P10221-ND for item 6. The cap you have selected is not rated for low ESR.

PlainBill

[nuhhht]

Re: Hanns G HG281D 2 second black screen and parts help

I went ahead and placed the order. Thanks Bill, and others for your help. Once all these are recapped I will report back with details.

[retiredcaps]

Re: Hanns G HG281D 2 second black screen and parts help

Did you mean FC? The FCs outnumber the FM by 6-2.

Here is what I came up with guys. Most are Panasonic FM series. Any critique is highly appreciated. Thanks!

1 2 P12415-nd Cap 470uf 35v Elect Fm Radial 0 0.61000 $1.22
2 4 P11230-nd Cap 22uf 35v Elect Fc Radial 0 0.33000 $1.32
3 2 P11250-nd Cap 10uf 50v Elect Fc Radial 0 0.28000 $0.56
4 2 P10224-nd Cap 1000uf 10v Elect Fc Radial 0 0.52000 $1.04
5 2 P10274-nd Cap 470uf 25v Elect Fc Radial 0 0.52000 $1.04
6 2 493-1024-nd Cap 470uf 10v Elect Vr Radial 0 0.28000 $0.56
7 4 P10278-nd Cap 1000uf 25v Elect Fc Radial 0 0.85000 $3.40
8 2 P12405-nd Cap 1000uf 35v Elect Fm Radial 0 0.97000 $1.94
9 2 P10313-nd Cap 2.2uf 50v Elect Fc Radial 0 0.26000 $0.52
10 2 493-1449-nd Cap 22uf 400v Elect Vz Radial 0 0.98000 $1.96

[nuhhht]

Re: Hanns G HG281D 2 second black screen and parts help

Yes, sorry about that.

[nuhhht]

I have some further questions while I wait for my caps from digi-key.

My monitor hasn't (in 2 weeks+) gone 2 second black screen on me. What I do experience is a slight distortion of wavy lines through my monitor briefly upon startup. Sometimes this continues for longer periods of times but it usually settles out.

I also notice faint grey lines (like the viewing of a video camera filming an old CRT monitor on TV). In my very new to electronics head (1 week of youtube/badcaps studying), this is telling me that either capacitors on the PSU is slowly charging but may not ever reach the required voltage thus causing certain aspects of the monitor to lose loads?

I'm really trying to learn this whole circuit board stuff and would appreciate some clarifying on certain parts and their uses. For instance on this board, https://www.badcaps.net/forum/attach...chmentid=16201 can someone do a quick ms paint of what different parts are? Thanks guys for helping me learn.

[PlainBill]

Re: Hanns G HG281D 2 second black screen and parts help

I have some further questions while I wait for my caps from digi-key.

My monitor hasn't (in 2 weeks+) gone 2 second black screen on me. What I do experience is a slight distortion of wavy lines through my monitor briefly upon startup. Sometimes this continues for longer periods of times but it usually settles out.

I also notice faint grey lines (like the viewing of a video camera filming an old CRT monitor on TV). In my very new to electronics head (1 week of youtube/badcaps studying), this is telling me that either capacitors on the PSU is slowly charging but may not ever reach the required voltage thus causing certain aspects of the monitor to lose loads?

I'm really trying to learn this whole circuit board stuff and would appreciate some clarifying on certain parts and their uses. For instance on this board, https://www.badcaps.net/forum/attach...chmentid=16201 can someone do a quick ms paint of what different parts are? Thanks guys for helping me learn.

Ratehr than mess with Paint, a quick description will have to suffice. Identifying components by appearance can be tricky. Resistors, capacitors, and inductors can be in several different packages, some of which are almost identical with one another. ICs can be in a number of different packages, and transistors - well, they can be in dozens of different packages.

The reliable method of identifying a component is by the circuit designator. Some common designators:
C - Capacitor
D - Diode
F - Fuse
IC or sometimes I - Integrated Circuit
J - Jumper
L - Inductor
Q - Transistor
R - Resistor
T - Tansformer
U - Integrated circuit
ZD - Zener diode
T - Transformer

The function of the basic components:

A resistor resists the flow of electricity, according to a formula knows as Ohms Law.
A capacitor resists a change in the voltage across itself by storing energy.
An inductor resists a change in the current through itself by storing energy.

As far as what the rest do, I suggest a little research.

PlainBill

[retiredcaps]

Re: Hanns G HG281D 2 second black screen and parts help

I started by reading Electronics for Dummies from the public library. Then I found a troubleshooting "modern" electronics book that explains various tests/fixes, etc.

Watching youtube vidoes on "what is a ????" also helped.

However, it wasn't until 6 weeks later when I starting using my friend's DMM that the "light bulb" suddenly switched on. No pun intended.

I also follow PlainBill's posts (old and new) and try to absorb.

It will come to you, but everyone's learning curve is different. After I fix 3 more LCD monitors, I'm going to tackle an AV receiver next.

I'm really trying to learn this whole circuit board stuff and would appreciate some clarifying on certain parts and their uses.