Hanns-G HG281D, LCD Monitor no power

[CATA2003]

Re: Hanns-G HG281D, LCD Monitor no power

Which board are they on - are they standard or smd do they have any marking on them

1. They are on the PSU board (on the feedback chain)
2. SMD
3. Don't have them (have been replaced with other value, now I will make it as the original one).

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

On the control board pw549da3 62c6-1549-1002
M06 ver5.0a can any one tell me what part number for Q14

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

I put cable from power suply in upside down and shorted Q14 looks like i put
12v in to it but is mosfet for power on switch and only need max of 5.x v.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

That's part number 9435GM

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

i seen that on older post but it was on a ver6 board

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

I dont know if bill is still watching but if you are.
Could you tell me if the key values that i should be looking at for a replacement, or any one else that knows

How would i check a voltage regulater for shorts. Sorry about the spelling.:-!

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

I ordered a new mosfet part number FDS9435ACT-ND from DIGI-KEY i hope it will be a good replacement can any one have a look and tell me if i made the right choice.

Thanks to all.

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

Here are some photos

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

Here are some good ones

[CATA2003]

Re: Hanns-G HG281D, LCD Monitor no power

Another problem strikes, I have replace the psu with an universal one and now the HDMI input is not working, I get a message on the screen that no input is detected an the digital one,but the VGA input is working.

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

check voltage reg's on the control board

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

I got my screen working now. After replacing the three small caps on the power supply as others did (C603,606 and 707) and replacing that mosfet I burnt. But I think that I need to recap the control board (logic board) and for sure the power supply. The image on the screen when I turn on the computer is shimmering. then it heats up and it look good.

I think that it's because some of the caps might be a little out of spec. so when they are cold they have hi ESR.

Any comments on this thinking

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

So did you replace those two 100uF 16V by the regulators on the main board?

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

I didn't replace any on the main board yet.

[budm]

Re: Hanns-G HG281D, LCD Monitor no power

Those two when bad can cause shimmering/lines on the screen, if you heat them up with hair dryer, the problem may clear up if they are not too far gone.

[Mark369]

Re: Hanns-G HG281D, LCD Monitor no power

Thanks budm

[Samsara]

Re: Hanns-G HG281D, LCD Monitor no power

Hello everyone,

I have a simple question (I think), but a long description. It regards the transformer in this image which is PHIHONG 26002170001, E149666 FIS-B1, 904040-001 0804 RA3, HI-POT.

It's on a PSM217-404-H-R power supply for Hanns G HG281D, hence why I'm posting here. I have very little understanding of electronics and after searching and trying to read through most of this thread I thought it best just to show a picture of what to me looks like the problem.

My screen has deteriorated in the following way over the last year:

- It started to take a while to get it to turn on, taking a few presses of the power button to get the blue "G" on and the screen would come on as normal.

- Those few presses turned into a LOT and I would spend 5-15 minutes pressing the button and it would eventually turn on.

- It became so bad that I would never turn it off with the power button and the screen would go to "sleep" (orange "G" power indicator) while the computer was off.

- The display would randomly disappear for a few seconds during normal use every now and then. This became more and more common.

- More recently, having kept it turned on, after turning off the PC and letting the monitor "sleep" it would die completely. No power light. Nothing.

- After turning on the computer and running it for a few hours the blue power indicator would flicker now and then and eventually, with no prompting other than the signal coming through the HDMI input from the computer, the screen would flicker into life and I'd have full display.

- Now that doesn't even work. Dead monitor.

Basically, does this melted, eroded transformer indicate the fault? Or does it sound like something else. I can provide pictures of different parts if needed.

Apologies if I've missed the answer in previous posts. I don't mind being directed to those answers to save time.

Thanks

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

Ok, your symptoms are classic for capacitors going bad. On that power supply normally the small capacitors in the middle dry up. Your picture of the switchmode transformer is interesting. With the melted plastic. I have never seen that before. Normally the brown residue is normal from the manufacturing process. What's important is the windings. I use a ring tester to test those windings.

Maybe somebody has another method for him to test it?

If it turns out the transformer is miraculously good. You need to change the capacitors circled in red on my photo. And it wouldn't hurt to change the ones circled in blue. That's almost always the problem with that power supply.

[Samsara]

Re: Hanns-G HG281D, LCD Monitor no power

Ok, your symptoms are classic for capacitors going bad. On that power supply normally the small capacitors in the middle dry up. Your picture of the switchmode transformer is interesting. With the melted plastic. I have never seen that before. Normally the brown residue is normal from the manufacturing process. What's important is the windings. I use a ring tester to test those windings.

Maybe somebody has another method for him to test it?

If it turns out the transformer is miraculously good. You need to change the capacitors circled in red on my photo. And it wouldn't hurt to change the ones circled in blue. That's almost always the problem with that power supply.

I've just plugged it all back in after replacing the capacitors you said to replace, and it works! Better than ever in fact. I hope it lasts!

Thank you very much for your advice. You've saved me. I really appreciate it.

[Lumberjack777]

Re: Hanns-G HG281D, LCD Monitor no power

Great to hear! You're welcome.

If you start getting any video problems like shimmering, color shifting, or fuzziness you'll need to replace the "two 100uF 16V by the regulators on the main board" as budm recommends in post #593. Those are usually the other capacitors that go bad.