Hanns-G HG281D, LCD Monitor no power

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

Forget about my last question please.

Should I have to order this, instead of buying those 3 caps?

http://lcdalternatives.com/Hanns-G-H...-P2087771.aspx

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

I bought these from Conrad. Are they ok?



The guy in the store said that the 35V caps will be ok, cause does not matter 16V or 35V. Is it true? I have never tried to repair anything like my monitor, so I hope I am not going to ruin it.

[bbcreativo]

Re: Hanns-G HG281D, LCD Monitor no power

Look here:

http://en.agreetao.com/taobao/view/id/41265938447

[bbcreativo]

Re: Hanns-G HG281D, LCD Monitor no power

Hi there, Folks...
I´m Bruno from Germany, (if there´s someone from Germany too, please contact me)


First I got a not functioning HannsG 281DJ for less. It is totally dead. No LED, nothing.
After a search for a Power Supply, I´ve found and bought another used one for 35Euros.
This one has the Power LED first blue, then yellow lighting. There´s an onscreen Display saying "Check Video Cable". Of course the Video Cable was connected right. I changed the board with the Video Connector from the other Monitor, but there was the same onscreen Message "Check Video Cable"

Today I found a way to buy 2 Power Supplies from China for the cost of 110Euros

Question: Are the Problems ever the Capacitors(Condensators)?

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

And to add to Lumberjack777's post above,
Please, DO NOT use Teapo SC capacitors. Those, too, will fail in a relatively short time. Use quality Japanese capacitors, such as United Chemicon (like the brown ones you already have on your board), Nichicon, Rubycon, Panasonic, and Sanyo.
I also highly suggest you DO NOT buy from eBay. While there are a few good sellers on there, 99.999% of the sellers sell COUNTERFEIT Japanese capacitors. Buy directly from either badcaps.net store, Mouser, Digikey, RS Components, or Farnell (I might have missed one more legit store or two, but you get the picture). Local shops are usually not a good idea either.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

Lucky you. That's the easier one to repair. Try replacing the 3 caps circled in red. Feel free to change any circled in blue if you want. But the 3 circled in red are usually the problem.

Make sure to pull straight out on the cap when desoldering. I have seen some botched repairs where the person pushed back in a little on the cap, and lifted the thin copper trace and pad. Those pads lift easily if you push on the cap.

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

Here are some.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

Ok, you fixed the main/logic board. That's good. Your problem with the power on, is on the power board. There are at least 2 different types of power supply board for this monitor. Can you post a picture of your power board, and I think we can help you fix this.

[Castor8]

Re: Hanns-G HG281D, LCD Monitor no power

Hi,
I am new here. I tried to find something/somebody to fix my HG281D.
I had the same issue like Inveio had. In summer it was working perfectly, but in winter I had to wait 2-3minutes or did something to warm up my monitor if I wanted to turn it on. I could not tolerat this thing anymore so I called somebody, who has replaced the bad caps (There was a couple of swolled caps on the supply board) . Than it worked ok for 2 months.
Then I wake up one day and I could not turn it on anymore. I tried to warm up with a hair dryer for a long time (as sometimes did before), but nothing has happened. Only the led indicator was flashing up for a tenths of a second. I could not turn it off anymore (Led indicator did not show the orange color) only the blue color flashed up sometimes.

I would like to fix it, because I like it very much, but I do not know what is its problem. It looks on the pics somebody tried to replace those 2 caps that Lumberjack777 mentioned above. I am afraid how to fix it, cause if somebody tried to replace those two (not the man I called) and did not help, what could be the solution.

Thanks for reading my story. 

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

No 12V/24V can be due to bad power supply or the logic board is not sending the PS_ON to turn on the power supply.
Did you use Low ESR/IMPEDANCE type caps? Did you replace the two caps on the main board?
Please up load good clear pictures of YOUR boards.

[lostsingle]

Re: Hanns-G HG281D, LCD Monitor no power

Hi all out there!!

My HG281D does something weird ,I replaced all the caps after that is was working smooth for about 2 months .
Now the power light comes blue but no backlight .

I have take some measurements and I don't have 12v or 24v on any off the pins from the power board.

What must or can I do to repair that issue ?
Hope that you can help me !

I have al the necessary tools to measure ...esrmeter -multimeter-oscilloscope..etc

thanks in advance

Lostsingle

[momaka]

Re: Hanns-G HG281D, LCD Monitor no power

OK. I've read all of the pages up to this point, even found the exact problem described that I have. Hanns-G 281D Rev.2. From a cold start the monitor turns on and works fine for about 3 minutes. Then black. LED indicates that its getting a signal from the computer. Using a flash light shows no image. Turn it off/on and I get the image back for about a second. So far I have replaced all of the caps on the power supply and the main board. No change. (probably not a cap issue) Not sure where to go next and am feeling a bit dejected that the caps didn't fix the problems. Any body have an idea what to do next?

If you used good quality caps (i.e., not Radio Shack, eBay for the most part, etc.) and they are low-ESR, then the problem likely isn't cap-related.

Something intermitten like this tells me it could be a bad solder joint or faulty regulator possibly. Since you can't see any image with a flash light when the problem occurs, my guess would be the problem is related either to the logic board (where the signal scaling/processing happens) or the t-con board (this is the board that "maps" the scaled signal on the screen - it's a board usually at the top of the LCD monitor under a metal shield and is permanently attached ot it via delicate ribbon cables).

How to narrow it down:
I think the best approach would be to take some voltage measurements before and after the problem occurs. These would be the 5VSB (5V standby comming from the power supply), the input and output voltages of the two regulators on the logic board (should be close to C80 and C83), and the t-con supply voltage (usually 5V or 3.3V for most monitors).

You will need a multimeter for this. All voltages should be referenced to ground (i.e. any metal part on the case of the LCD - attach negative (black) lead of the multimeter to that).

And last but not least, add pictures of your monitor!

[rspendl]

Re: Hanns-G HG281D, LCD Monitor no power

@jimmy1256 Try measuring the voltage at the power supply. If +5VSB is stable all the time (even when the monitor turns off), this circuit is OK, otherwise use better quality capacitors C601/602/603, possibly C707. If some other voltage fluctuates it might be regulators or one of the U(101, 102, 201...) chips. When replacing caps, I've almost broken a pad next to U201 once (as user Steven_C on this forum also did), so try checking whether there was some damage done when replacing caps. Might be something completely different, but this is something to start with. In any case, voltage measurement on power supply is where you should start.

[jimmy1256]

Re: Hanns-G HG281D, LCD Monitor no power

OK. I've read all of the pages up to this point, even found the exact problem described that I have. Hanns-G 281D Rev.2. From a cold start the monitor turns on and works fine for about 3 minutes. Then black. LED indicates that its getting a signal from the computer. Using a flash light shows no image. Turn it off/on and I get the image back for about a second. So far I have replaced all of the caps on the power supply and the main board. No change. (probably not a cap issue) Not sure where to go next and am feeling a bit dejected that the caps didn't fix the problems. Any body have an idea what to do next?

[invenio]

Re: Hanns-G HG281D, LCD Monitor no power

I've repaired about 10 of these. It's always the same caps. The ones on the power board. And the two on the main/logic board as Budm mentioned. If you replace just those 2 you'll probably be fine. Many, many, of the other caps are still good. And it's a waste of time and money to even replace them. Try replacing these 2.

Got the 2 caps for the main board in the mail yesterday and replaced them. Great news, the monitor is working as new. No flickering, no 10 minute warmup,... everything back normal. I wonder now whether there were bad caps on the power board at all. Regardless, thank you for all the help. If I didn't find out about replacing just those two caps on the main board, I probably would not have gone through the trouble of taking it apart again.

For those reading this and having similar problems. Replace those two caps on the main board. It only costs about $3 (with s/h) from digikey for those two extra caps.

[invenio]

Re: Hanns-G HG281D, LCD Monitor no power

Link doesnt work this is what you need
http://www.digikey.co.uk/product-det...391-ND/2433525

Great. Thanks. I made the order so hopefully next week I can give an update on the outcome.

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Link doesnt work this is what you need
http://www.digikey.co.uk/product-det...391-ND/2433525

[invenio]

Re: Hanns-G HG281D, LCD Monitor no power

Just use panasonic FM or FR whatever you can get that will physically fit.
Same values as the ones you have.

Would this be a good option: http://www.digikey.com/scripts/DkSea...35008274923241

Sorry if this is a dumb question, I don't know too much about electronics so I rather double check everything before ordering.

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Just use panasonic FM or FR whatever you can get that will physically fit.
Same values as the ones you have.

[invenio]

Re: Hanns-G HG281D, LCD Monitor no power

I've repaired about 10 of these. It's always the same caps. The ones on the power board. And the two on the main/logic board as Budm mentioned. If you replace just those 2 you'll probably be fine. Many, many, of the other caps are still good. And it's a waste of time and money to even replace them. Try replacing these 2.

I think I will try and replace those two then. Do you have link to a specific cap that you find worked well for you?