Hanns-G HG281D, LCD Monitor no power

[DIODE]

Re: Hanns-G HG281D, LCD Monitor no power

Use a resistor as suggested below

https://www.badcaps.net/forum/showpo...9&postcount=45

I tried a 3.3k jumper from PS-ON to 5vsb and still no 5/12/24 volts, I measured no AC voltage going to the primary winding of the xformer in the center of the board. See attached pdf pic with voltages with 3.3k jumper from PS-ON to 5vsb, the 4.89v shown is the voltage measured on the PS-ON circuit with 3.3k jumper PS- to 5vsb. The PS-ON signal connects to Q702 and it appears to function. 174VDC is measured across the large cap downstream from the 120vac bridge rectifier.
Any suggestions would be helpful, thank you for all help provided thus far.

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

How come the transformer is not soldered in place? I can see blank holes with the traces going to the rectifiers for the 24vdc outputs.

[DIODE]

Re: Hanns-G HG281D, LCD Monitor no power

How come the transformer is not soldered in place? I can see blank holes with the traces going to the rectifiers for the 24vdc outputs.

The transformer is in place and all pins are soldered, See post 214 - the transformer was removed and reinstalled, the post 214 picture of the foil side was used to ilustrate what voltages are present at PS-ON after reinstalling the transformer, the post 214 pics are the best focus and exposures of the foil side I have.

[Kaun]

Re: Hanns-G HG281D, LCD Monitor no power

I just looked at the pictures of the power supply you have posted, I really suspect those caps to be bad, see PDF. You can try heating them up with hair dryer to see if the lamp will light up steadily, unless the caps are really dried out.

After reading through all of these post, while noticing some great tips and patience, I came across this post and thought "what else do I have to lose".

This was what the issue was here and once I heated caps and board up after just a couple minutes of blow dryer application I plugged the AC cable back in and the lights all came on as they should.

I will be paying attention to this monitor for a while now but I wanted to ask if this is a sign of something that I should now be looking to work towards fixing or just make sure that the monitor does not get shut off again to cool down?

The monitor works great now and has no visible issues.

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

That can be the sign of small value caps (Electrolytics type 22uf and less) are failing, that is from my experience. Look at the area where you heat up to see if there are any small value caps around. But that does not eliminate cold solder joints and bad semiconductors. Easy to put in 25 cents caps to find out.

[DIODE]

Re: Hanns-G HG281D, LCD Monitor no power

The transformer is in place and all pins are soldered, See post 214 - the transformer was removed and reinstalled, the post 214 picture of the foil side was used to ilustrate what voltages are present at PS-ON after reinstalling the transformer, the post 214 pics are the best focus and exposures of the foil side I have.

If anyone has a schematic of this power supply or very similar power supply I would appreciate knowing, the power supply is "PHIHONG model PSM217-404-H-R , the monitor model is; I-INC IF281D , similar to HANSPREE 281D.

I appreciatte all help and assitance. Thank You

[onyx00]

Re: Hanns-G HG281D, LCD Monitor no power

Well I just fixed one of my monitors this weekended. Replaced the usual suspects mentioned in this thread on the power board, but what finally did it was replacing some on the logic board.

Bad news is I went to do the second monitor I have (same model), and my Weller WES50 went crazy - heats up to maximum temperature. I didn't noticed until I had badly burned some of the leads/holes. I got it back together and working fine, but needless to say I'm none to happy with Weller and need a new iron.

[tom66]

Re: Hanns-G HG281D, LCD Monitor no power

Newer Weller irons seem to be made in China crap, instead of the old German made units which were very nice, although I've never had the pleasure of owning one.

[mclarengt]

Re: Hanns-G HG281D, LCD Monitor no power

I Have read through all of these posts multiple times, and am having a somewhat different issue. The power light stays orange, but no video at all. I was looking through the mess of posts and saw no similiar issue, and on the power board, The 2 yellow double caps (at least that is what I read they are) labeled Carli have no continuity(I know you would rather know the ESR, but I have no access to an esr meter.) I was hoping for a bit of help on what might be wrong, as I have found nothing similiar posted here.. Any Help would be appreciated!!

[DIODE]

Re: Hanns-G HG281D, LCD Monitor no power

Whne the monitor is plugged in and the LED goes blue then amber the monitor is powered up but not detecting an input or the main board that takes the input has a problem. As a first step connect video to a different input, HDMI input or the VGA input to illiminate lack of input as the problem. If the video souces is confirmed and tried on both inputs and still no blue led I suspect the main board not recognizing the video input(main board= board with VGA/HDMI connectors) This is based on my knowledge og the I-INC IF281D monitor that is likely simialr to the Hanspree 281D , Good Luck

[mclarengt]

Re: Hanns-G HG281D, LCD Monitor no power

It does not get a blue power led at all. It turns orange as soon as you plug in the power cord, and as a correction it flashes, Which from what I have learned indicates it is getting an overload somewhere correct? It gets absolutely no video, regardless of anything I have tried.


[edit] It is also an HF289H which is similiar to the 281

[DIODE]

Re: Hanns-G HG281D, LCD Monitor no power

I cannot be certain about the LED operation for that model. However, if the power supply is labled "PHIHONG model PSM217-404-H-R" The following applies
On the header connection is printed in very small white lettering Gnd, 5v, 5vsb, PS-on,12v and 24v. If PS-ON is between 3.3 and 5.2 volts the other voltages should be present if theye are not the problem is on the Power supply. If PS-On is below 3.3 the power supply is not getting a power up signal from the main board.

[Recycler]

Re: Hanns-G HG281D, LCD Monitor no power

@mclarengt:
That logic board is quite different from my logic board (HG281D).
It looks like it has heated up, judging from te PCB color, top&bottom.
If you have the 5VSB (amber led as you said, but trace and measure anyway) then it could indicate a failure on the logic board.

There are two big regulators on that logic board, try to measure the input and output of those components.

Cheers.

[vfnpunk]

Re: Hanns-G HG281D, LCD Monitor no power

I am having the EXACT same problem on my HANSPREE HF289H as mclarengt. Pretty much no power or response from the monitor anywhere. The only response ill get is when I plug it into my pc or any type of video source, I'll get that orange light flashing once then nothing. Now I found parts of the monitor fairly cheap, I just want to isolate the problem and buy the right one. I was told its the inverter board, but couldn't it also be the power board and the video board? Ill post pics as soon as I upload them but mine looks a lot more burnt than his

[kukri]

Re: Hanns-G HG281D, LCD Monitor no power

Here are some high res pictures.. ugh costs several hundred to repair. I guess I need to know which resistors to replace so I will start the research. Nothing looks messed up here.. >

[kukri]

Re: Hanns-G HG281D, LCD Monitor no power

Ok for the dumber guys like myself... I have read the thread and since I don't have much knowledge about the topic, only understood some of it. However, I can solder. Could we just have pictures (I can provide the images) of all the boards and all the needed capacitors that need to be replaced circled? Perhaps make a list? This way, even though some of us might replace parts that weren't yet bad, at least we will eliminate 90% of the possible issues.. ideas? I'm sure like me, a lot of people find this thread to see if they can fix their monitor and end up not understanding anything that is written here. And the only time I soldered and used voltmeter was with my car. Also I feel like if I replace the most necessary ones my monitor will work again (as it only turns off at the beginning of operation and flickers rarely with white background). I read the names of capacitors to replace.. but which ones are they on the boards? No idea..

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

@ kukri
Hi - welcome to the forum. If you have read all this thread you should realise this may not be an easy fix. How do you think we can give you a list of what is on your board? As these boards are made, the manufacturer is always changing updating items - if it is needed you will have to do it.
Whilst the pictures are good they are not exactly what we need - we need ones like in post3.Then list the questions asked by retiredcaps and put your answers in. That will give a good start.
Care when working on open boards 300-400 volts may be present.
Do not allow boards to touch each other and do not work on a conductive surface
Measure voltage with power on
Measure resistance with power off (for 5 minutes)
You will need to follow instructions carefully.
Perhaps practice with your meter a bit measure resistances on things switched off to get used to holding the probes and looking at the meter at the same time. We have had a few costy errors recently.
All items on the boards are numbered if you do pictures as requested and quote board numbers
we will both know what we are talking about.

[Recycler]

Re: Hanns-G HG281D, LCD Monitor no power

Also I feel like if I replace the most necessary ones my monitor will work again (as it only turns off at the beginning of operation and flickers rarely with white background).

The power supply has United Chemicon caps.
You forgot to post pics of the logic board, my problem was similar to yours and it turned out to be faulty caps on the logic board.

Cheers.

[kukri]

Re: Hanns-G HG281D, LCD Monitor no power

Okay I will try to post some pictures soon

[charleseo]

Re: Hanns-G HG281D, LCD Monitor no power

I was just given a hg281d which is not working, every so often when i press the power button i get a little flicker of blue in the bottom right power light but I have not managed to get anything else out of it, Is there anyone out there willing to try to help me threw this, if so I will take some picks tomorrow of the boards inside.. this will be my first attempt at fixing a problem like this so it might take baby steps. The monitor is beautiful, owned by a old lady that prolly never even put a fingerprint on it. she just bought a new monitor and that's how i got my hands on this