ACER AL2423W - no display

[QuickFix87]

Re: ACER AL2423W - no display

I have recently fixed such a monitor. It went black after several minutes in use. Replacing 7 capacitors CS 10/11/12/13/14/15/16 fixed this problem. At least 3 of them were clearly broken. Replaced all of them for the surefire result.
Also, the resistor R59 on the same power unit PCB seemed to be burnt. It was in black dust. I wiped this dust. Its body looked whole. I detached it. Its resistance was 826 KOhm. I thought it was too high for that place and concluded that it was broken. And read its color rings backwards. The resulting resistance that I calculated this way was either 1.3 or 13 KOhm 0.5%. I was unsure as the brown ring looked almost identical with the red.
Yet, after first replacing the original 826 KOhm resistor with a new one of 1.3 KOhm the screen was black even with good capacitors. After a while I figured that those 826 were close to the standard 820 KOhm, so it was fine. I put back the original resistor and the screen started ok.

[dondrusco]

Re: ACER AL2423W - no display

I received brand new power board for AL2023. Problem still persists - I have to continue with control board, it looks like backlight-on signal falls too low. Power led stays green.

I have another chance to swap parts between three monitors.
Gericom T2000 - faulty LVDS cable
Acer AL2023 - turns the backlight off after a while
Acer AL2423 - backlight problem.

AL2023 + logic board from AL2423 - backlight problem persists
AL2023 + panel from T2000 (the same model/revision) - backlight FIXED!
Some CCFT has a problem
AL2423W - recapped primary capacitors (C22,C24,C25,C30,C32) - backlight FIXED!
Couriously, the T2000 backlight works fine with no issue with panel from AL2023...

[juhae]

Re: ACER AL2423W - no display

Hi, my ACER 2423 backlight turns on only by unplugging inverter board cable from the PSU. Just short flash was visible during power on. After power on: Disconnecting/connecting pin 6 makes backlight to turnon. I cut the cable and soldered a switch to make short cut in on/off backlight control.
I have to replace caps from primary side of 19 V.

Here is link to shematics:http://www.manualslib.com/download/2...Acer-X241.html

Ha! There is no diagram of power board AND Pin is 1 ( not 6). Sorry for mistakes!

[juhae]

Re: ACER AL2423W - no display

Hi, my ACER 2423 backlight turns on only by unplugging inverter board cable from the PSU. Just short flash was visible during power on. After power on: Disconnecting/connecting pin 6 makes backlight to turnon. I cut the cable and soldered a switch to make short cut in on/off backlight control.
I have to replace caps from primary side of 19 V.

Here is link to shematics:http://www.manualslib.com/download/2...Acer-X241.html

[desqa]

Re: ACER AL2423W - no display

Hello.
I'm trying to fix monitor with the same power supply as mentioned in post #5 - DELTA ADP-58AF. I replaced all the capacitors and main MOSFET (Toshiba 2SK2843) but found out that Zener diode right next to it is shorted... And here's my problem, I don't know the value of this diode (ZD4). I can't find any schematic for this power supply, and the only information I have is the marking of the diode that remained on the glue after desoldering... I think it's either "81" or "18". Is it possible that this is a 18V Zener or is it some other marking?

Any help would be greatly appreciated, thank You.

---
Below are photos before and after desoldering.

[Behemot]

Re: ACER AL2423W - no display

Most likely it was so bad, having high ESR thus heating itself.

[Blacklite]

Re: ACER AL2423W - no display

Thanks for your help so far. I'm pretty confident I can do all this, as long as I can find the right parts. Does anyone have a schematic for this board? I tried searching for one last night but no luck...

Also I'd like to know where all that heat came from too, so I can be sure that replacing these caps will prevent it from happening when I plug it in again. Anyone got any ideas?

[Behemot]

Re: ACER AL2423W - no display

Yep. Use quality low-ESR caps for the bigger ones and low-ESR or GP purpose for the small ones - there have a look into datasheet to gain the idea what the replacement parameters should be.

As for the high-voltage input cap, I suggest lines like NCC KXJ and similar, they have very long life (10000+ hours).

I just by the way got the display again, the diode once again burned itself but now completely; probably the leg was too much oxidized and the solder did not attach it even it seemed that way. Since I didn't have 1kV+ standard diode, I have used 5A/1,7kV diode from old CRT TV/display in TO-220F package and used parts of it's legs as conductor also. It has slightly higher drop but is bigger thus should also transfer heat better. Hopefully it will last this time, it's soldered propely. If not, there would be interesting effects

[tron]

Re: ACER AL2423W - no display

replace the others too (all of them)

[Blacklite]

Re: ACER AL2423W - no display

Can't seem to edit my post... Oh well, here's another picture of the board from a different angle:

[Blacklite]

Re: ACER AL2423W - no display

I have the same monitor, and after 3.5 years of faithful service, it's finally given up. It started hissing/beeping (blowing cap sound), so I turned it off, then turned it on again and got no picture and the beeping was still going, so I turned it off again.

Now I've taken it apart, and it is pretty clear where the culprit lies:



It's the biggest capacitor on the PCB, marked "C1".

When I touched the back of the screen as I started to take it apart, I noticed it was very hot to touch. The plastic was very hot, and the screw holes for the stand almost burnt me. There are a few burn marks on some of the components around the bulging capacitor in the picture. Not sure which bits are relevant exactly, but I'm going to get my photographer colleague to take a quick picture of it tomorrow at work (my phone's camera is a potato).

There are also black marks (burn marks?) along where the heatsink above these components meets the PCB. I believe this all happened when the capacitor blew.

Should I just try replacing the bulging capacitor? I can't seem to find a schematic for this board, the service manual for this monitor doesn't have it as far as I can see.

I have a fair idea of how capacitors work and I know they can be very dangerous. I've done plenty of soldering before and basic electronic stuff, is this something I should be tampering with? Realistically, my only alternative is to throw the whole thing out and buy a new screen (replacing the power board is too costly considering the current value of the screen).

Thanks in advance!

[Winstar]

Re: ACER AL2423W - no display

Well another 5 years would be enough for me... Then will be time to buy an OLED monitor

But I am afraid to buy the board(s) and not fix the problem... In addition I don't think backlight will last forever, but I must say I used it almoust always at minimum brightness

[Behemot]

Re: ACER AL2423W - no display

Can be whatever more or less, but new board has the same crapacitors and will fail again, is it worth? I'd say 30 euros is pretty much money…

[Winstar]

Re: ACER AL2423W - no display

Hi all,
I have an acer al2423w failed some weeks ago after 5 years of work. Image is OK but there is a purple irregular shape vertical line on the center-left of screen. The line increased day after day until it reached the whole height of the screen. I am thinking of replacing logic and power boards, i can find both for 30euros on ebay. In your experience do you think this is a cap fail ? I am not used to soldering so i prefer change the whole board... Do you think i'll fix the problem or it can be a true LCD-panel fail?
thanks a lot

[pedro]

Re: ACER AL2423W - no display

I've got a similar issue with my Acer x241w ...

Whenever you have a different model, regardless of how similar the symptoms are it is always recommended you start a new thread for that specific model. Model-to-model differences mean that specific detail (such as the capID's you quoted) are meaningless or even misleading.

[bimmerd00d]

Re: ACER AL2423W - no display

I've got a similar issue with my Acer x241w, no backlight but i can see the signal with a flashlight. I've pulled the boards out and inspected the caps but didn't find any visibly bulging or leaky ones. I went ahead and replaced the big ones and 2 smaller ones. CS10,11,12,13,15,16 with a kit i got from LCDalternatives.com. I have a picture and the monitor is responding to a DVI cable plug/unplug. If i let it go to standby (orange light) then plug in my DVI cable to my laptop it goes green and I see an image on the screen if i shine a flashlight. The fuses and caps on the inverter appear to be fine, i checked the fuses on the inverter board with my MM and they 0 out. Here's the weird thing, according to Tonnes he got 19v when he tested the inverter cable. I'm seeing 3.2v with my laptop hooked up and the power light green. Something's jacked up here and I can't seem to find it. I am the only owner of this monitor as well, nobody's cracked the seal except me. FYI, I am not very good at reading schematics, and by not good I mean it's russian to me. All this talk of 19v rails has me in the fetal position.


EDIT: Well, after i took the cable off to measure the voltages, i put it back on and tried it. Now it's working. Not sure how long it'll keep working now, but whatever, the wife will be happy she can have her monitor back now

[dondrusco]

Re: ACER AL2423W - no display

I received brand new power board for AL2023. Problem still persists - I have to continue with control board, it looks like backlight-on signal falls too low. Power led stays green.

[Behemot]

Re: ACER AL2423W - no display

I've remeasured actuall voltage on caps in the 20" of mine cause I've forgotten it - and quite suprisingly found there is even arround 19 V coming into inverter part (some 18,5 V under load). I am happy Chemi-Con KY caps are so overrated cause I filled the first display with caps up to 16 V.

I would suggest 18 V than, maybe more…

[dondrusco]

Re: ACER AL2423W - no display

ZD270 is transil unipolar, 600W 16V P6KE16A - but is there any correct replacement?

15V or 18V? 16V is out of stock

[Behemot]

Re: ACER AL2423W - no display

I don't have any display opened now, can't tell.

But in my case, we have room full of these displays and they usually start turning off and on right after turnign them on first time. They did this by themselfs, no button action needed so I think this is only capacitor problem for me. I believe that using good Samxon GF 10 uF caps will be OK, they should hold for long time. But I may position them slightly off the heatsink in some non 90° angle