Acer X223W power problem - Panel?

[Jerryv]

I have searched for similar issues without success so I thought I would start a new thread.

On power up the power LED just blinks on and then off repeatedly. I suspected bad power supply caps, but on dis-assembly nothing was obvious. Most problems seem to be related to the backlights, but while trying to check those I found that the power will stay on if the ribbon cable is disconnected from the panel. The backlights work just fine in this case, but of course there is nothing displayed. The panel is an LG LM220WE1 which I have found a data sheet for that shows the pinout on the ribbon cable connector, but unfortunately nothing on the electronics of the board. It looks like 5 volts is supplied to the panel through the ribbon cable and I suspect that the panel is overloading the power supply which causes it to shutdown and restart repeatedly. The panel circuit board looks like it may have voltage regulators to reduce the 5 volts further but I haven't had much luck deciphering the part numbers. I am wondering if anyone else has seen something like this and had any luck repairing it.

I actually have three of these with the same symptoms so I thought it might be worth putting a little time into it. Seems like it might be a common problem with this model.

Thanks
Jerry

[budm]

Re: Acer X223W power problem - Panel?

Or can be weak 5V power supply due to bad cap: I.E start up cap.

[Jerryv]

Re: Acer X223W power problem - Panel?

More Info:

By chance a fourth identical unit showed up in the recycling bin so I gave it a try. It worked, but had an annoying flicker. This gave me a chance to do some parts swapping and comparative testing. When I put the #1 and #2 boards on #4 panel they each worked (I couldn't really evaluate the flicker) so I was more convinced the panels were bad, but then I put the #4 boards on the #2 panel and that combination also worked although the backlight blinked off once before staying on. I did notice an odor of ozone though, so I am now suspecting a lamp problem.

I connected #2 boards back to #2 panel and it still cycles on and off so the #4 boards must be less sensitive to problems or something. I found that if I unplug one or the other lamps, the 5V stays on, but of course the connected lamp just blinks.

I will have to make one of the CFL test lamps and try that. I think I have a 13W one somewhere.

It looks like it may be time to pull a panel apart and see what the lamps look like. I have not done that yet.

Jerry

[momaka]

Re: Acer X223W power problem - Panel?

Could still be bad caps in the power supply, even if none of them look bad. I suggest you post some pictures of the power supply. Some caps will just not bulge when they go bad.

[Davi.p]

Re: Acer X223W power problem - Panel?

Your swapping test results makes some confusion, is there a possibility you made a mistake?
You have the panel's d.sheet, can you power up the panel n.1 or 2 or 3 with external psu and connect it to the N.1 , N.2 and/or N.3 boards? ensure that there's an onboard fuse.
NOW.. i have to go BATH

[budm]

Re: Acer X223W power problem - Panel?

" I did notice an odor of ozone though" That is one clue of high voltage arcing for sure.
I was able to smell an Ozone and the lamp were flickering, check the wires attach to the lamps were OK, not until I decide to remove the black shrink tubing off the wire then I saw the cause of the problem.
http://s807.photobucket.com/user/bud...tml?sort=3&o=0

[Jerryv]

Re: Acer X223W power problem - Panel?

Finally got a chance to work on these a little more. I took the lamps out of the #4 panel ( the one that had the flickering problem). The top lamp had some discoloration on the ground end. I then took these lamps and plugged them one at a time to the number 2 monitor. With the bottom lamp from number 4 in place of the top lamp on number 2, it looked like I had a good combination so I took apart the #2 panel and put in the lamp. The reflector had to be turned around to match which wouldn't be difficult except the ground wire is stuck to the back of the reflector. After re-assembling #2 completely, it works like a champ. One down and three to go.

The ground wire on the flickering lamp was loose and arcing. I will try to reattach it and check the lamp again. Looks like I will have to order at least some lamps.

The protection circuits on the first three power supplies must be more sensitive than the one on the fourth. I am still puzzled that unplugging the panel allowed the lamps to work on the first three, but it must be just enough extra load to trip the shutdown.

This forum is great!

Jerry

[Davi.p]

Re: Acer X223W power problem - Panel?

"The protection circuits on the first three power supplies must be more sensitive than the one on the fourth. I am still puzzled that unplugging the panel allowed the lamps to work on the first three, but it must be just enough extra load to trip the shutdown."
I don't find any logic in this situation.. and i have never heard of a blinking led with a lamp problem..


(i was joking before, i don't had to go bath)
(why in english tube=tubing??)

[selldoor]

Re: Acer X223W power problem - Panel?

OFF TOPIC

"


(i was joking before, i don't had to go bath)
(why in english tube=tubing??)

I have difficulty in understanding what you are on about a lot of the time
Are you asking about TUB not tube as in
http://dictionary.reference.com/browse/tub

[Jerryv]

Re: Acer X223W power problem - Panel?

"The protection circuits on the first three power supplies must be more sensitive than the one on the fourth. I am still puzzled that unplugging the panel allowed the lamps to work on the first three, but it must be just enough extra load to trip the shutdown."
I don't find any logic in this situation.. and i have never heard of a blinking led with a lamp problem..


(i was joking before, i don't had to go bath)
(why in english tube=tubing??)

I don't think I understand the comment. The LED I was referring to was the indicator in the power switch. It shows blue when the power is on and orange when the monitor goes to standby. Pretty common. Most switch mode power supplies will shutdown if they are overloaded and then try to restart. I suspect this is what was happening in this case.

Jerry

[Davi.p]

Re: Acer X223W power problem - Panel?

in post 7 you have repaired mon. #2 by replacing light tubes but you said in the post 1 that the led was blinking, this is an uncommon mode.. also the fact of detaching the ribbon and the supposed overload don't seem to have to do with bad lamps, as inverter are self protected and if a lamp draw too much current that stops transistors to drive lamp transformers.

Selldoor: "Are you asking about TUB not tube as in"
It was only a curiosity , when i translate with google, TUBE is = to TUBING why?
i've read in this thread "heat shrink tubing" i knew only the word "tube"

[selldoor]

Re: Acer X223W power problem - Panel?

OFF TOPIC

Selldoor: "Are you asking about TUB not tube as in"
It was only a curiosity , when i translate with google, TUBE is = to TUBING why?
i've read in this thread "heat shrink tubing" i knew only the word "tube"

I got to TUB thinking you were referring to BATH.

When we read "tubing" in context - plastic tubing, glass tubing we just understand it means plastic tube, glass tube, whether that is a correct use for it or not.
here is a dictionary definition
http://www.thefreedictionary.com/tubing

I dont know how that will translate as I know very little Italian

[Davi.p]

Re: Acer X223W power problem - Panel?

OK Selldoor thanks , i've understood the difference now but google translates badly..

[Jerryv]

Re: Acer X223W power problem - Panel?

Update:

I have now had a chance to work on these a little more and it turns out they all had the same problem. The wire going to the far end of the top bulb was disconnected and arcing. By far end, I mean the end opposite where the wires come to the bulb. A little cleaning, soldering, a dab of silicone sealer and they are operational again. Taking the panels apart to get to the bulbs is a bit touchy, but with care it is not hard. The heating/cooling of the bulbs must eventually break the connection and lead to this problem or else there was a bad batch that got through production.

Thought I would throw this out there in case anyone else runs across this model.

Jerry

[selldoor]

Re: Acer X223W power problem - Panel?

That is good to hear Acer monitors are known to have bulb problems in certain models - this must be one of them.
Thanks for reporting back.

[Yatti420]

Re: Acer X223W power problem - Panel?

It seems pretty common with the Acer Xseries monitors.. I have 1 X193W that is flickering pretty badly and makes nasty noises when you plug in the power cord.

[budm]

Re: Acer X223W power problem - Panel?

@jerryv, If you can smell the Ozone, that will be one of the clue. Glad to hear you got it fixed. AM radio is also good detector for electric arcing.