Hanns-G HG281D turning OFF on HDMI waving on VGA

[accxer]

Hello everyone. I have been reading this forum for a quite wile now, loads of good information.
However i have a quick question regarding my old Hanns-G monitor.
The monitor turns off if i plug it via HDMI (blue light is constantly ON).
Now if i use analogue (VGA) there's two green (sometimes one) lines appear on the right side of the monitor as well as the picture itself is wavy.
It needs good 30 mins before monitor back to normal (waves and green light disappear).
Now after monitor warms up (after an hour or so) i can sometimes switch the cable to HDMI and monitor works just fine.
I have tested voltages while monitor is on stand-by (i get steady 4.98V on one output) in addition i get +12 and +14 if the monitor is in its active state.

What do you think can cause such a behavior?

Thank you and sorry for my English

[jetadm123]

Re: Hanns-G HG281D turning OFF on HDMI waving on VGA

The caps on the logic board (the same board you plug your video cables into) are a known problem for your model monitor. You can first try the usual things like removing the ribbon cables from the logic board, cleaning them, and reseating them. If that doesn't work, replace the caps.

[accxer]

Re: Hanns-G HG281D turning OFF on HDMI waving on VGA

thanks for your reply, previously i have replaced 22uF 400V cap on power supply board (it measured low capacitance). No ripple on any of the output DC.
Now i have replaced two 100uF 16V caps on logic board (got 60uF and 0.6uF readings for those). Please see the pictures attached.
Changing those two caps fixed blinking issue as well as there is no flickers or any other artifacts on the screen except the vertical green line.
Where should i look to fix that?
Much appreciate your help.

[retiredcaps]

Re: Hanns-G HG281D turning OFF on HDMI waving on VGA

Changing those two caps fixed blinking issue as well as there is no flickers or any other artifacts on the screen except the vertical green line.

Carefully re-read jetadm123's post #2. If you haven't reseated and cleaned every internal connector on every board, then do so or say that you have done so.

Also, jetadm123's advice was to replace ALL the caps on the logic board. Unless you have an ESR meter and tested every capacitor out of circuit to verify they are good, there is no way of knowing if the capacitor is good or not.

[Th3_uN1Qu3]

Re: Hanns-G HG281D turning OFF on HDMI waving on VGA

The green line looks like a panel defect. It most likely has nothing to do with the logic board.

If cleaning and reseating the LVDS cable going from the logic board to the panel does not fix it, then the problem is likely to be bad tab bonds from the Tcon to the panel, and cannot be repaired. You can try tho. Take off the metal shield of the Tcon and run your finger over the flex cable ribbons going to the panel. If you're lucky, the green line will go away when you touch a certain area. This can sometimes be fixed by figuring out something to keep the ribbon pressed in place.

[jetadm123]

Re: Hanns-G HG281D turning OFF on HDMI waving on VGA

Since the green line goes away after 30 minutes, try using a hair dryer to accelerate the removal of the green line. First, heat up the logic board caps with the hair dryer. If the line goes away, then replace the remaining caps. If the line doesn't go away, heat the ribbon cable tab (where the cable end is bonded to the LCD pane) associated with that line. If the line goes away, then it's a panel defect and not repairable.

[accxer]

Re: Hanns-G HG281D turning OFF on HDMI waving on VGA

Thank you guys for your inputs.
I have used ESR meter to test the caps on a logic board.
Also have cleaned the cables prior posting on this forum.
Now for the green line, strangely i have carefully pressed the screen with my thumbs and moved it a bit (the screen actually moves around).
After this the green line disappeared, this screen is a bit of a joke. Well at least now i can use it as a secondary screen so that my wee girl can watch movies.
Will let you know if the green line comes back.

[budm]

Re: Hanns-G HG281D turning OFF on HDMI waving on VGA

Please see this thread:
https://www.badcaps.net/forum/showth...632#post254632