Hanns-G HG281D

[Liquadia]

I am experiencing a problem with my Hanns-g Monitor and before I delve into opening it I would like to know what i should be looking for other than bulging caps.

Basically The monitors backight turns onand off it appears as I cant see nothing. Everything else works fine however i do notice that it flickers alot depending on what screen Resoloution its set at, the lower the less flicker the higher the more flicker sometimes its stable for ages then flickers and gets worse

At present its flickering quite a bit and going from 1920x1200 to 800x600 causes it to stay on and not flicker

What can i do about this! or look for

Is it a power issue



I have taken apart the monitor just now! and seems fine capacitor wise, ill have to try and work out which 1 is faulty how?

[selldoor]

Re: Hanns-G HG281D

Ok It may help us to help you if you post pictures - have you checked the caps bases to see if any have pushed out. Many caps show no external damage or bulge - even a slight dome suggests it is bad.
What make of caps and series are in there - some are known to fail.
As well as caps it may be voltage regulators- pics will help us point them out for testing.
Welcome to the forum-
We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

It will be useful if you can say a bit about yourself - skills tools etc.


As mentioned by Budm most caps should be replaced except perhaps the BIG ones - the ones that seem to cause most problems are C80 and C83

[budm]

Re: Hanns-G HG281D

Did you see the post I replied before you moved to the monitor forum:
https://www.badcaps.net/forum/showth...370#post282370
The two caps are on the main board by the regulator.
http://s807.photobucket.com/albums/y...t=DSC00085.jpg

[Liquadia]

Re: Hanns-G HG281D

Many Appologies for not noticing whats been going on in previous posts! Been kinda rushed to get this monitor open. Being low on cash and not being in work i struggle to keep the monitor on on times.

The monitor seems to work and the power {blue light} stays on when there is no picture! {when the backlight goes off}. the back light does flicker on and off fast sometimes between on and off it takes sometimes 2-5 seconds other times within half a second.

When i first powered on the monitor I heard a Buzzing noise come from the power supply unit! Picture ending 0477, and 0479 shows the area of which is on the left side of the image, i am assuming its the coil wrapped in copper, next to that up against the heatsink is a brown capacitor i think. In front of that there is a i think mosfet resistor! wasnt sure if that was causing it doesnt seem likely. On pic 0479 you will see 3 coils top left, thats where i hear the Buzzzz sound briefly when turning on and off the monitor via switch. It makes this noise when the lights turn on! once the lights are on it is quiet, even when they flicker on and off

Couldnt see no dry joints or lack of solder, who knows....

regarding my skills I have worked in various factories soldering and placing components on boards, as to what the names are on some components today is anyones guess. I done this type of work when i was in my early twenties, now im 39.

I am a qualified computer engineer with 8years field experience work installing and repairing computer systems, networks.

hope the images are sufice..


Forgot to add, it started making dots on the screen as well like flashing dots vertical from top to bottom equally spaced apart about 2-3cm from left to right like this


. . . .
. . . .
. . . .
. . . .
. . . .

their not dots like that above but rather more squished sorta dots rectangle in shape small and also flicker on and off like the matrix weird..
im assumings its all related to power!

[budm]

Re: Hanns-G HG281D

The two caps on main board as shown in my pictures is from the monitor with pictures and black out problem, when they are bad it will cause the screen to go black when the resolution is set higher than 1024x768, it will also cause noise on the screen.
The buzzing problem you are hearing in the power supply is another problem which also needs to be dealt with. This power supply is known for running hot and cause caps to go out, cap can look normal but can have high ESR. I would suggest you to replace all the caps in the power supply, except the large DC filter cap (450V), and the two caps on the main board.
There are so many thread on this monitor model in this sites.
Panasonic FM/FR series should be used.

[Liquadia]

Re: Hanns-G HG281D

I shall look for these capacitors in maplin electronics maybe they have them there! for the psu, and the 2 for the main board ill get the ratings of them. FM/FR Series capacitors throughout i take it? mainboard and psu

[budm]

Re: Hanns-G HG281D

Yes. try the two caps on the main board fist.

[Liquadia]

Re: Hanns-G HG281D

Yes. try the two caps on the main board fist.

ok many thanks for your patience and time. I will get these caps and test it out When i get some coin next.

I will also let you know how it goes.

Best Regards
Jake

[budm]

Re: Hanns-G HG281D

You may also want to read this thread also so you not have the bad connection on the T-CON not seated properly after caps replacement. Right now the voltage reading on the two regulators on the main board may be reading low due to bad caps.

https://www.badcaps.net/forum/showthread.php?t=23592

[Liquadia]

Re: Hanns-G HG281D

Seems they dont have them in stock! any ideas as to where i can get them online

[selldoor]

Re: Hanns-G HG281D

They rarely have stock of suitable caps its good that they didnt palm you off with some rubbish ones. RS online http://uk.rs-online.com/web/ are usually ok but i dont know what their min order/post charge is like. They have a sales counter in pontypridd if you can get there.

[Liquadia]

Re: Hanns-G HG281D

their delivery is Free! next day.

Their capacitor brand is Rubycon are they ok to use

YXF Al electro cap,100uF 16V 105deg C
224-4173

Rubycon
16YXF100M6.3X11
RoHS status: Compliant

http://uk.rs-online.com/web/p/alumin...633D4E4F4E4526

Capacitance 100μF
Construction Radial
Diameter 6.3mm
Dimensions 6.3 Dia. x 11mm
Height 11mm
Lead Diameter 0.5mm
Lead Pitch 2.5mm
Leakage Current 3 μA
Lifetime 5000h
Maximum Operating Temperature +105°C
Minimum Operating Temperature -40°C
Mounting Type Through Hole
Ripple Current 250mA
Tolerance ±20%
Tolerance Minus -20%
Tolerance Plus +20%
Voltage 16 V dc


Or there's this

http://www.ebay.co.uk/itm/100uf-16v-...item4ab1c53560

[selldoor]

Re: Hanns-G HG281D

Go with RS ( by the way, I have no connection with them) and the Rubycon YXF

Although the ebay guy has 100% feedback I have not heard of Panasonic M and the picture is of caps made by Doubillier -why it says Panasonic on the pic I dont know.
Doubillier might make some low esr caps but they also make the caps that maplin sell which are not suitable for this purpose.

[retiredcaps]

Re: Hanns-G HG281D

Or there's this

http://www.ebay.co.uk/itm/100uf-16v-...item4ab1c53560

I have mentioned several times now in various Hanns-G 28 inch monitor threads that these lcds run temperature hot and dry out caps on both the power and main board. The damage done will not be obvious and can only be found using an ESR meter.

Using 85C caps like the ones in the above ebay auction is not a good idea.

For a 28 inch monitor, spend the few extra $$$ and get high quality caps from a reputable distributor.