Yet Another Hanns-G HG281D Thread...

[stingray072]

Sorry to post another thread on this cursed monitor but yesterday my display started doing something wacky that I haven't seen anywhere else in this forum.

My monitor had been working fine, when in the middle of watching a video the screen started to turn white, from left to right, almost like it was bleaching out. The display then stayed completely white- about as bright as it could be. I turned it off, turned it back on, same thing.

The display turns on fine, blue light, then after a few seconds orange, and stays on at orange without shutting off, making think this is not a power supply issue (but of course I'm writing here because I don't know what's wrong so please correct me if you know better!). I've isolated the fact that the display turns white, regardless of input, but rather as a response whenever anything comes up on the screen. For example, when the display first powers on, led turns blue, the box would come up that says no signal input, and the display would go to standby. A second after I press the menu button and the menu comes up, the display whites out.

I tried reseating connections, inspecting the boards for bulging caps but didn't see any (even though that doesn't mean there aren't still bad ones), and testing continuity over the f400 fuse on the Tcon board. I really don't know much about this, but new monitors this size are over $400 where I am now, so any ideas or recommendations of things to test would be incredible.

[budm]

Re: Yet Another Hanns-G HG281D Thread...

It can be these two caps in the logic board that are common failure.
http://s807.photobucket.com/albums/y...NNSG%20HG281D/
Try replacing them first since they should be replaced any way.

[stingray072]

Re: Yet Another Hanns-G HG281D Thread...

It can be these two caps in the logic board that are common failure.
http://s807.photobucket.com/albums/y...NNSG%20HG281D/
Try replacing them first since they should be replaced any way.

Thanks for the info! Which two caps are you referring to specifically- the pictures above had a few C80 and C83?
If those caps were the bads one, should I expect to see a relief of symptoms if I heat them up with a blowdryer or the likes?

[budm]

Re: Yet Another Hanns-G HG281D Thread...

These two caps:
http://s807.photobucket.com/albums/y...t=DSC00085.jpg

It depends how bad the caps are, if they dry out so much, then heat may not help at all.
Caps in the power supply for this monitor (same as used on some of the Viewsonics Monitors) will need to be replaced also. I suggest these two caps first since they are easy to do.

[stingray072]

Re: Yet Another Hanns-G HG281D Thread...

Well I replaced the two caps you indicated, and lo and behold the display started working again.

I started to notice a lot of small flickering on blacks and whites, and then after about an hour of use, the screen went completely white again. Sigh*

So I guess I probably need to recap the whole main board (I already have the caps for that), or would I probably also need to recap the power supply?

[t.j.]

Re: Yet Another Hanns-G HG281D Thread...

where the caps low esr? or ratshat/source generic?

[stingray072]

Re: Yet Another Hanns-G HG281D Thread...

I don't know if the caps are low esr but they're supposed to be the right caps for this board. I just ordered them within a set off of ebay. The 16v 100uF ones say 1NEB if that means anything, but it replaced the crappy cap-x ones....

[budm]

Re: Yet Another Hanns-G HG281D Thread...

Chweck the voltages outputs of those two regulators.

[stingray072]

Re: Yet Another Hanns-G HG281D Thread...

Hi budm,

Please excuse my ignorance and thanks so much for you help, but what regulators? Do that mean the two capacitors? And how would I check the voltage exactly? I have a multimeter, but not sure across what two points I would be checking. From the + to - parts of the capacitor? When it's on or off? Help much appreciated. Thanks!

[mariushm]

Re: Yet Another Hanns-G HG281D Thread...

http://s807.beta.photobucket.com/use...ml?sort=3&o=12

Those two black chips at the bottom right corner.

Put the meter on Voltage DC, put the black probe tip on that ring to the left, and then put the red probe tip on the pins of those regulators.
On the left chip, one pin should have 1.8v or something very close to that, on the chip to the right one pin should have 3.3v

Write here the measurements for both if you're not sure of the values.

[Jerzy54]

Re: Yet Another Hanns-G HG281D Thread...

Hi all,
I'm new to this forum and I'm trying to recap a main board and power supply board on my
Hanns-G HG281D. I was reading that the best way to do it is to replace all the caps.
Well I have trouble to find some Panasonic caps on Digikey. I can find all the caps except the following:

power supply board
10uF 50V
2.2uF 50V
47uF 50V
1uF 100V
10uF 35V

main board:
470uF 16V

Can anybody advise where can get these caps.

Thanks,

[stingray072]

Re: Yet Another Hanns-G HG281D Thread...

http://s807.beta.photobucket.com/use...ml?sort=3&o=12

Those two black chips at the bottom right corner.

Put the meter on Voltage DC, put the black probe tip on that ring to the left, and then put the red probe tip on the pins of those regulators.
On the left chip, one pin should have 1.8v or something very close to that, on the chip to the right one pin should have 3.3v

Write here the measurements for both if you're not sure of the values.

Sorry its been so long, but I didn't have time to mess with this until finals were over.

For the left chip, from left to right, I got 0, 1.75, and 3.24 (all negative). For the right chip, again from left to right, I got 0, 3.24, and 4.85 (also negative).

The static seems to show up more when the screen shows whites, and it's really intense with certain kinds of greys. Also I have it taken apart to measure the voltage and theres a pretty audible buzzine noise coming from either the power or controller board. Is it worth totally recapping the rest of the controller board since I have the caps for them, or would some of those caps be better used on the power board. I still have 3x16V/100uF, 3x16v/470uF, and 12x 16v/10uF. Thanks!

[budm]

Re: Yet Another Hanns-G HG281D Thread...

You should replace at least those two 100uf 16v on the main board for those two regulators, and most of the cap (except the large filter cap on the primary side)

[stingray072]

Re: Yet Another Hanns-G HG281D Thread...

You should replace at least those two 100uf 16v on the main board for those two regulators, and most of the cap (except the large filter cap on the primary side)

Hi Budm,

Thanks as always for your help. I'm afraid I'm a little confused by your terminology though:


Main board = the board where the inputs are?

And the two 100uf 16v for those regulators - Are these the two you mentioned in the post above here? http://s807.beta.photobucket.com/use...00085.jpg.html
If so I replaced those two first, and that's what got me to even be able to keep the monitor on . It was a great fix to at least get me through the rest of the semester.

The primary side = ? Is this the side with the caps on the same board, referring to only one part of that board, or perhaps something on the power board?

Large filter caps = Are those the 470uF caps?

Sorry for all the questions. I'm trying to make my way through the other threads but I'm not a electronics guy so its kind of a steep learning curve.

[budm]

Re: Yet Another Hanns-G HG281D Thread...

Main board = the board where the inputs are? Yes.

And the two 100uf 16v for those regulators - Are these the two you mentioned in the post above here? http://s807.beta.photobucket.com/use...00085.jpg.html: Yes.

Large filter caps = Are those the 470uF caps? The biggest cylinder one, 450VDC rating.
If so I replaced those two first, and that's what got me to even be able to keep the monitor on: This will stop the monitor from blacking out when use the native resolution, but if the power supply is really bad, then that is not going to help. If you also have bad caps in the power supply board, it can damage the circuits.

[stingray072]

Re: Yet Another Hanns-G HG281D Thread...

This will stop the monitor from blacking out when use the native resolution, but if the power supply is really bad, then that is not going to help. If you also have bad caps in the power supply board, it can damage the circuits.

Hmmm. So what would your recommendation be? Should I replace the other caps on the main board near the voltage regulators (aside from the large filter caps), or you think that there are problems with the power supply board, and I need to replace caps there, or replace the board entirely?

[PhrygianKat]

Re: Yet Another Hanns-G HG281D Thread...

Interesting read, I have the same monitor and am about to endeavor on the same cap changing journey. I don't mean to intrude on a thread, however, the OP mentioned something that caught my eye. You had to change the 470uf caps to run at native res without blackouts??? I don't have this whiteout issue mentioned by the OP but I do have a scenerio were the monitor won't wake from sleep and occasionally it tries and flashes an image several times before total blackout.
The monitor works fine over HDMI, if I leave it on and don't allow the computer to sleep, or if I don't turn off the display while leaving the computer on and then attempt to turn it back on again after a nap. The VGA signal sleeps and wakes just find, however it shows some sort of static interference within the image that reminds me of a 60 cycle humm on the old school stuff. I am using a $450 power conditioner for filtering though, so it can't be interference.
Do you guys think that I am dealing with the same underlying issues? Bad caps? Thanks!

[budm]

Re: Yet Another Hanns-G HG281D Thread...

The large 450v does not go out too often, but other electrolytics caps on the power supply board should be replaced at the same time, and at least the two 100uf/16v on the main board by the regulators.

[Lumberjack777]

Re: Yet Another Hanns-G HG281D Thread...

The large 450v does not go out too often, but other electrolytics caps on the power supply board should be replaced at the same time, and at least the two 100uf/16v on the main board by the regulators.

I had a Hanns-G 28" that had a strange flicker, and a sort of static on the video.
I replaced those two 100uf/16v on the main board you recommended. Fixed the problem and saved me a ton of time. Thank you!

[reddeth]

Re: Yet Another Hanns-G HG281D Thread...

I'm getting ready to replace the capacitors on both the power supply board and the video controller board, as has been suggested in this (and other) threads. However, I'm still pretty new to ordering capacitors, I've found the correct micro-farad and voltage rating, but I'm not sure what else "matters" when selecting capacitors. Mouser gives an option to sort for "audio grade" or "general use" (and a few other options), is one better than the other? If temperature is the problem with these monitors, would I be better off trying to get high temperature capacitors?

Sorry if this isn't the best place to ask this, I felt it was relevant since I'm experiencing the same issue and I really want to pick capacitors based on their use (this monitor).