Hanns-G HG281D, LCD Monitor no power

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

We rarely provide lists of caps as we have no idea what version of any particular board might be in your set. The manufacturers sometimes make amendments to the values they use even on the same board versions.
The best way is to simply list the caps you have on your board and then look up the datasheets and see what is available at digikey. You need the same voltage and uf value and same or better esr. You should also make sure they will physically fit.

If you look a few posts up there is an example of this -

[videoman5]

Re: Hanns-G HG281D, LCD Monitor no power

I know I could do that, but I'd rather not open it up and blah blah blah. But I am going to have to open, won't I?

I'm a lazy electronics engineering major.

[Crais]

Re: Hanns-G HG281D, LCD Monitor no power

Replacing those two caps worked great (two hours into testing). Thanks Lumberjack and Budm.

Videoman5, I just happen to have the list I made for mine right in front of me. As selldoor pointed out this may or may not apply to your board but you can probably compare yours to mine on the previous page to see if they appear the same.

Mainboard:
3x 16v 470uF
5x 16v 100uF
12x 16v 10uF

PSU: Mine is apparently one of at least two different models.
2x 35v 1000uF
2x 16v 1000uF
2x 25v 680uF
1x 25v 220uF
1x 10v 220uF
1x 16v 100uF
1x 35v 33uF
4x 50v 10uF

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

"Replacing those two caps worked great " That is great. If running on low resolution allow the monitor to stay on, then that is always the sign of those two bad caps on the main board are bad.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

You had that one nailed way back in post #427 Bud. I'm going to add that to my diagnostics routine. I learn so much from you, and retiredcaps, rtech, jetadm, and the others. Thanks for all you do guys!

[ngstime]

Re: Hanns-G HG281D, LCD Monitor no power

Hello,

Great thread, bad HG281D here too...

Symptoms:

• Blinks blank, sometimes stay blank. Seems to work best after warmed up than cold
• Dark pages drives it nuts, blinks like crazy
• Runs fine at 640x480, no issues at all
• Brightness/Contrast doesn't work very well, always a click away to resetting to default 100/70
• Occasional pop sound from the back. Can't recall what was going on that caused this, seems like it was resetting resolution (like quitting a game).

I've read a lot of this thread, and picked up quite a bit.
Looking at the caps, they all appear fine visually

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Start by changing the caps C80 and C83 (pic 1/2) then if that fixes it consider changing the caps on the power supply.
A cap that looks bad is bad
A cap that doesnt look bad is probably bad given the symptoms you describe.

[doramjan]

Re: Hanns-G HG281D, LCD Monitor no power

I've got another bad HG281D.

It started turning on only after the second or third click of the power button, but got progressively worse. Now, when I press the power button, the blue power light turns on for a moment and turns off. Pressing the power button more times will not immediately cause the blue power light to turn on. It will only turn on momentarily after a 'cooldown' time of about 5-10 seconds. After a handful of tries, it used to turn on eventually and be more or less OK until it was turned off again. Now all I get is the brief blink of the blue power light.

I've peeked at the caps, and none are bulging or leaking. I have ordered replacements for the most common problem capacitors discussed on this forum. I have no idea if replacing caps will fix the problem.

Does anyone have any specific advice?

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Bad caps can look normal. Try setting the video resolution to the lowest setting to see if it will stay on, if it does, then you need to replace the two caps on the maon board. tehn you should also replace a set of caps int he power supply.

[JonM]

Re: Hanns-G HG281D, LCD Monitor no power

I know, same old song here. Just one more for the list...but I have one symptoms I didn't see anyone else mentioned. First I have the blackout problem. It stays on for a few minutes and then shuts off, no blue or amber light on. If I reboot it comes on but the same thing happens after a little while. I looked at all the compositors, no bulges and no leakage. I have tried low resolution, same thing. Now the thing I noticed is while the screen is off and I disconnect the HDMI cable and plug it right back in, the screen comes back for a few minutes. I forgot to take pictures of the logic board, but all of those capacitors also looked like the ones on the power board. Any suggestions? ...

[Ritalin]

Re: Hanns-G HG281D, LCD Monitor no power

Anyone have the values for C301, C302, and C401? My father removed them and threw out the caps thinking they were all the same value, but didn't have the caps in stock, so.. ya.. no clue what's suppose to go there...

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

jonm, read post 427 and later. Bad cap can look normal.

[jleon92f]

Re: Hanns-G HG281D, LCD Monitor no power

Yes C80 and C83 are usually the ones to change on the main board
They are 100uf16v and the ones in the digikey link will be fine.

should they be low ESR type ? I am trying to use 100uf 50v ones that I have handy?


100uf_50v by jleon92f, on Flickr

Thanks,
John.

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

should they be low ESR type ? I am trying to use 100uf 50v ones that I have handy?


100uf_50v by jleon92f, on Flickr

Thanks,
John.

Please dont ask the same question in two threads- Budm has already answered this?

[jleon92f]

Re: Hanns-G HG281D, LCD Monitor no power

Bad caps can look normal. Try setting the video resolution to the lowest setting to see if it will stay on, if it does, then you need to replace the two caps on the maon board. tehn you should also replace a set of caps int he power supply.

Do they have to be Low ESR type?

Thanks,
John.

[jleon92f]

Re: Hanns-G HG281D, LCD Monitor no power

Please dont ask the same question in two threads- Budm has already answered this?

Hi, I am sorry. Where did he answer this. The Digikey link shows a Regular Cap, Not low ESR? Is this OK.

C80 and C83 100U/16V http://www.digikey.com/product-detai...391-ND/2433525



Thanks,
John.

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

Hi, I am sorry. Where did he answer this.
.

https://www.badcaps.net/forum/showpo...2&postcount=51

The Digikey link shows a Regular Cap, Not low ESR? Is this OK.

C80 and C83 100U/16V http://www.digikey.com/product-detai...391-ND/2433525



Thanks,
John.

The Digikey link shows a Panasonic FR series cap which is considered Low ESR

Whilst Digikey label it as general purpose if you compare the esr figure with
other available caps of the same size and values it will be relatively low.
It is not Extra Low so can be used in this application.
Ideally you should look for a datasheet for the original cap (not an easy task) and match the ESR, as for some applications too low an esr is bad.

[jleon92f]

Re: Hanns-G HG281D, LCD Monitor no power

https://www.badcaps.net/forum/showpo...2&postcount=51





The Digikey link shows a Panasonic FR series cap which is considered Low ESR

Whilst Digikey label it as general purpose if you compare the esr figure with
other available caps of the same size and values it will be relatively low.
It is not Extra Low so can be used in this application.
Ideally you should look for a datasheet for the original cap (not an easy task) and match the ESR, as for some applications too low an esr is bad.

Thank you..after putting it back together, there is NO video now at all? So I guess I screwed something up. It worked before, just had a flicker and would go out sometimes. Should have left it alone..Oh well.

I guess I have to buy a New monitor. The power on and off works great! just No picture or the Analog message in the middle of the screen.

Thanks,
John.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

Thank you..after putting it back together, there is NO video now at all? So I guess I screwed something up. It worked before, just had a flicker and would go out sometimes. Should have left it alone..Oh well.

I guess I have to buy a New monitor. The power on and off works great! just No picture or the Analog message in the middle of the screen.

Thanks,
John.

Sounds like you forgot to plug something back in. Check all the connectors, and the connector to the inverter board, and the one to the lcd. You are probably ok, just missed a connector somewhere.

[jleon92f]

Re: Hanns-G HG281D, LCD Monitor no power

Sounds like you forgot to plug something back in. Check all the connectors, and the connector to the inverter board, and the one to the lcd. You are probably ok, just missed a connector somewhere.

Thanks, I have it apart again and checking. I did use the 100uf 50v caps on the logic board? But it should still show something on the screen,right?

John.