Looking for some Help Hannsg HD281D flashing BLUE led startup

[rawlings42]

Hi guys, Feeling a complete idiot at the moment, fixed the distorted video and switching off after 10 secs, with replacement caps on the video signal board

After 1 hour of trouble free testing, unplugged mains and started to rebuild.

after i disconnected the lead from PSU to Inverter board it grounded out ( i think) and i heard a loud discharge noise.

Since then Blue led flashing only.

Checked all the main capacitors recommended for replacement elsewhere, all measured in limits with Fluke multimeter, uf seem all OK.

have 5v but no 12v or 24v, inverter board not lighting up. Flashing blue LED only.

Are there any people out there with some checks to do?.... HELP

read a little about startup capacitors, but have i popped something more serious?
No obvious signs of damaged componants etc

I have a background in electrical/electronics but feel stupid after fixing this unit then damaging it ...aaarrrrghh

[selldoor]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

Pictures need to be a bit sharper and need main board and panel board.
Just say again what happened.
Which end of which cable do you think grounded? on what? Pins are usually covered on leads and open on board? so it would be all plastic? or were the boards loose and grounded on the frame?

What is the part number of the power supply board and does the heatsink come off easily or is it soldered.

[Th3_uN1Qu3]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

You have either shorted a diode, or simply blown a fuse. You say you don't get 12v or 24v. Check for fuses on those rails.

[rawlings42]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

Pictures need to be a bit sharper and need main board and panel board.
Just say again what happened.
Which end of which cable do you think grounded? on what? Pins are usually covered on leads and open on board? so it would be all plastic? or were the boards loose and grounded on the frame?

What is the part number of the power supply board and does the heatsink come off easily or is it soldered.

Thanks newer photos attached,
fixed original fault with digital input board, all ok working fine,
When it came time to fix all boards into place and full rebuild - this happened...
as i disconnected the cable from psu to inverter board it touched the rear of the lcd panel, and sparked across - this is when i heard the discharge noise.

I cant say for definate that it wasnt the psu shorting, this was in its place in the rear cover at the time, and it was being moved with the cable at the time it went bang.

I have another monitor and swapped the PSU out , all ok
So im confident the panel and the input board are still ok and fully working , the fault lies within the psu board.

Hope that gives a bit better indication

PSU p/n 71-y2831200g001, heatsinks are screwed on top but the soldered.

thanks

[selldoor]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

You will need to check for fuses on the power supply board as we cant see them.
Could be any shape or size - if your not familiar -google images fuse will give ideas
if you can see the board designations should be Fxxx but refer anything with an F in it.

On the main board I cant spot any fuses but there are around a dozen components labeled FBxx Some are zero resistors and some are ferrite beads - can you test them all as if a fuse. Report any that are higher than touching your probes together

[rawlings42]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

You will need to check for fuses on the power supply board as we cant see them.
Could be any shape or size - if your not familiar -google images fuse will give ideas
if you can see the board designations should be Fxxx but refer anything with an F in it.

On the main board I cant spot any fuses but there are around a dozen components labeled FBxx Some are zero resistors and some are ferrite beads - can you test them all as if a fuse. Report any that are higher than touching your probes together

Hi Thanks, there is only 1 main fuse, thats OK , nothing else labelled with an F prefix, some 0 rated surface mount pieces all OK, thanks for your advice tho'
dave

[budm]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

Is this the same as yours?
http://s807.photobucket.com/albums/y...NNSG%20HG281D/
There is the PS_ON isganl form main board to the power supply board to turn on the the 12/24V power supply circuits.

[rawlings42]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

Is this the same as yours?
http://s807.photobucket.com/albums/y...NNSG%20HG281D/
There is the PS_ON isganl form main board to the power supply board to turn on the the 12/24V power supply circuits.

yep looks exactley the same,

i have 2 same monitors, 1 perfectly working ok, took psu board and placed in the faulty display and all worked ok.
so my (smaller) pcb the main board is ok??
swapping the main psu only made the faulty unit work.

thanks the pson signal does sound right though

dave

[budm]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

OK, you have verified that the power supply is bad for sure, and since you have two power supplies, one is good, one is bad, then you can compare resistance reading between the two boards.

[rawlings42]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

OK, you have verified that the power supply is bad for sure, and since you have two power supplies, one is good, one is bad, then you can compare resistance reading between the two boards.

Yep I know, but using the other as working PC monitor, dont want to strip down but, if i have to. Wanted to see if anyone could help rather than blindly checking. Appreciate your help

dave

[budm]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

Without the diagram and without knowing which pins got shorted out will make it hard to troubleshoot, but you can at least do some visual inspection, and Transistors/Diode/IC checking with the meter will be the starting point.
Also try to download the data sheet of the IC so at least you will know how they are used.

[rawlings42]

Re: Looking for some Help Hannsg HD281D flashing BLUE led startup

Thanks all