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Old 05-05-2010, 01:05 AM   #1
severach
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Default Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

I got 4 of these in with no back light. The TDK TBD292LF EA02B292T PK07V00330I A668.TBD292LF.TDK XinE 2 inverter has quantity 10 of 100uf 35v 105*C (NK CON) WK CON EVL series capacitors. EVIL they are too. The first two monitors I fixed by replacing bulged caps C34, C35, C36, and C38 which get burned up by Q6 and Q4. I left the remaining non bulged caps. All I could find at the time was some 100uf 25v 85*C 2000 hour Nichicon VR caps. These ended up working fine for more than a year and were not damaged when removed. The other two monitors had the same 4 caps bad but they didn't work after fixing. MOSFETs Q6 and Q4 near the bad caps were shorted so I tried to swap in the NICO P2804BDG and P5504EDG from Q3 and Q5 to get one board working but it didn't. I didn't notice all the fuses on this inverter and I didn't have any good tools to remove the small stuff so I couldn't get any farther.

Nice detective work on the oddball MOSFETs at Need help finding replacement transistors and more possible replacement items for when the MOSFETs go at Electronics Forum: Acer AL2416W value of F2, then replace the Q4, Q6

Lately the AL2416 I kept starts dim and brightens within a few minutes. I thought this might normal CCFL operation but I decided to open it anyways to see how the substandard temperature caps are holding against the heat because spare boards are rare on eBay and letting the caps go bad for too long results in dead hard to find MOSFETs and who knows what else. The Nichicon caps were fine but now I have more caps and better equipment so I replaced them with some lower ESR 100uf 25v 85*C 2000 hour Chemicon SMG caps and greatly improved the soldering quality.

The power supply is equipped entirely with Rubycon YXG caps and the big semiconductors all have heat sinks. FSP100-4F01, FSP100-4F02, FSP130-4F01 look like good power supplies that won't see many capacitor failures. All caps tested great.

The AA668 VL-2401 REV:1C video board caps Lelon 220uf 16v and 22uf 16v tested fine. A few of the Chemicon 100uf 16v 105*C KMG caps tested a bit high so I replaced C159, C135, and C154.

So I put it all together and it flickers. Fortunately I notice that the flickering is affected by how I move the screen. I pull it back apart and the inverter cable is loose on both ends. My fault of course, but getting these connectors to seat is harder than it looks.

Yet another year later I hear a pop and see some steam out of the monitor. Even with one magic smoke released it kept on going. As a consumer I'd ignore this and forget to mention it to the service tech when the monitor finally goes. Knowing that the MOSFETs are at risk I cut power immediately.

Now the room smells like stale peanuts. Open it back up and the next 4 are going C1, C2, C3, and C39. The sleeves seem heat discolored compared to the remaining two C29 and C4. One has popped, one has bulged out the bottom, and the other two are as fine as they can be near the end of their life. It's a big monitor with a lot of lights that runs pretty hot and the 85*C SMG and VR caps are still going good and that's all I have so I put 4 more in and the monitor is back in operation.

It seems odd to me that the left and right side of the TDK inverter are probably the same circuit and the layout is different.
Attached Images
File Type: jpg Acer AL2416 Monitor.jpg (377.2 KB, 546 views)
File Type: jpg Acer AL2416 Inverter 1.jpg (454.6 KB, 592 views)
File Type: jpg Acer AL2416 Inverter 2.jpg (463.3 KB, 531 views)
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Old 10-07-2010, 06:52 PM   #2
Lagunapete
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Excellent tech work. I have replaced the four caps on the upper half of the inverter board previously and my customer said she was swapping a computer and when she plugged in the monitor there was no screen image.

Checking on this, I noticed that the problem is not the backlighting which is working fine. This time there is a problem on the video board. No startup logo or any imaging at all.

C159, C135, and C154 as you mention above checked out OK as well as the remaining caps.

I'm beginning to think that it may be the ribbon cable. If only the designer spent another day or two on this model, I believe it may have been more reliable (aside from the caps they had gotten from their vendor).

One oddity I noticed is that my revision omits the entire connector in the corner of the board next to the ribbon cable.

RE: AA668 VL-2401 REV:2A
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Old 10-25-2010, 07:15 PM   #3
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Hi. I also have the same monitor, one day after trying to connect my ps3 to the monitor via hdmi - dvi connector cable it suddenly stop working. Shows Acer logo then monitor went to standby (front panel light turned amber). The same problem when i tried connecting the monitor to my working pc. One thing i noticed was the hdmi - dvi cable i used is no longer working (test it with another monitor and pc). So i opened the monitor but didn't see any bad/bulging/leaking/burnt caps on all the boards. I'm suspecting power supply problem.?? How can i test the power supply outputs safely?
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Old 10-25-2010, 07:18 PM   #4
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Quote:
Originally Posted by dt2rz View Post
I'm suspecting power supply problem.?? How can i test the power supply outputs safely?
Quick clarification. Right at this moment, with a known good cable, known good source, does the Acer logo still show up on power up?

To test the power supply, you will need a multimeter. Funny, we just talked about this 15 minutes ago here ...

http://www.badcaps.net/forum/showthread.php?t=11726

However, before you do that, just clarify the logo question above.
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Old 10-25-2010, 07:35 PM   #5
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Thanks for the quick reply. "yes" Acer logo still shows for about 3-5 seconds and then screen turns black and the front panel light of the monitor went from green to amber. I dont have a multimeter right now, maybe i will buy tomorrow.
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Old 10-25-2010, 07:43 PM   #6
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Whoever said the fsp power supply was good-well a few are but fsp is turning into crap like raidmax and powmax. Now of course i know nothing about their lcd psu offerings hut im expecting the same crap...
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Old 10-25-2010, 07:55 PM   #7
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Quote:
Originally Posted by dt2rz View Post
Thanks for the quick reply. "yes" Acer logo still shows for about 3-5 seconds and then screen turns black and the front panel light of the monitor went from green to amber. I dont have a multimeter right now, maybe i will buy tomorrow.
Okay, another couple of questions.

1) If you hookup a known good video cable and a know good source, do you see the display on the LCD if you shine a flashlight on it?

2) If the image does show up, does it "flash" briefly and then go off?
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Old 10-25-2010, 08:42 PM   #8
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

-Yes, i can still see the Acer logo upon shinning the flashlight.
-Yes, logo flashes briefly and then says 'no signal' and then turns off (light on front panel turn amber)
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Old 10-25-2010, 09:25 PM   #9
jetadm123
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

From the looks of post #1, now would be a good time to post some photos of the entire power supply (front and back with the steel cover off) and inverter (front and back). See links below:

http://www.badcaps.net/forum/showthread.php?p=118105

http://www.badcaps.net/forum/showthread.php?t=1868

And welcome to the forum!

Last edited by jetadm123; 10-25-2010 at 09:28 PM..
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Old 10-25-2010, 09:43 PM   #10
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

OK, I will take some pics. Thanks.
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Old 10-25-2010, 10:11 PM   #11
retiredcaps
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Quote:
Originally Posted by dt2rz View Post
-Yes, i can still see the Acer logo upon shinning the flashlight.
-Yes, logo flashes briefly and then says 'no signal' and then turns off (light on front panel turn amber)
One more question right now.

If you hookup a computer (that is what I meant by a source in the previous posts), can you see the display briefly and with the flashlight?

This last answer will tell us which direction to troubleshoot.

Last edited by retiredcaps; 10-25-2010 at 10:27 PM..
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Old 10-25-2010, 11:35 PM   #12
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Quote:
Originally Posted by retiredcaps View Post
One more question right now.

If you hookup a computer (that is what I meant by a source in the previous posts), can you see the display briefly and with the flashlight?

This last answer will tell us which direction to troubleshoot.
Oh i see. Hook up to the computer that i'm using right now and shine my flashlight to the screen but no display can be seen. After showing 'acer' logo and then 'no signal' the screen is just black (its like on standby or turned off)
Here are some pics: I noticed something abnormal on the power supply which i circled red..
Attached Images
File Type: jpg acer24-1 001.jpg (310.5 KB, 330 views)
File Type: jpg acer24-1 003.jpg (344.6 KB, 277 views)
File Type: jpg acer24-1 006.jpg (365.0 KB, 338 views)
File Type: jpg acer24-1 011.jpg (302.2 KB, 363 views)
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Old 10-25-2010, 11:44 PM   #13
mathog
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Take the metal plate off the power supply and show us what is under it. The covered section is where one often finds failed capacitors. (Not on this board in particular, I don't know anything about this board in particular, but it is the part of typical power supply boards where the 12V and 5V are regulated.)

Edit: It is even marked for you, see it says "secondary" just next to that plate.

Last edited by mathog; 10-25-2010 at 11:50 PM..
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Old 10-25-2010, 11:47 PM   #14
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Quote:
Originally Posted by dt2rz View Post
Here are some pics: I noticed something abnormal on the power supply which i circled red..
I'm not sure what that is on the transformer. The fact that you are getting a power LED and a "no signal/logo" suggest that most of the power section is working fine.

Is there a way to take off that shield (with the serial number and Rohs sticker) so we can get a peek underneath?
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Old 10-26-2010, 01:55 AM   #15
bonney
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Acer AL2416W
Inverter TDK P/N TBD292LF
10 capacitors 100uf 35v miniature
Fuse F2 marking M
Q4 faulty P2804BDG
Q6 can go faulty P5504EDG
Q3 faulty P2804BDG
Q5 can go faulty P5504EDG
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Old 10-26-2010, 01:59 AM   #16
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

If Q5 and Q6 are weak they give you half brightness on the left side same if you dont use P5504EDG P2804BDG
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Old 10-26-2010, 08:21 AM   #17
jetadm123
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Try removing the metal cover plate by reomoving the two screws on top. Also, "feel" along the bar code label for a "hidden" screw. If this doesn't release the plate, then look underneath the power board for screws.

Again, we need to see what you're seeing, which means we need to see photos of the entire boards top and bottom.

Last edited by jetadm123; 10-26-2010 at 08:23 AM..
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Old 10-26-2010, 10:53 AM   #18
mathog
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

That's the first power supply board I have seen with a shield plate like that. More typically the power supply/inverter/video card are al mounted on the back of the LCD panel and a single box-like shield bolts down over all of them. I wonder if they didn't put this plate on because of interference within the box between the power supply and the video card? In any case, that shield is going to seriously restrict airflow through the secondary part of the power supply, which will raise temps, which would tend to make the electrolytics in there fail (even) faster.
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Old 10-26-2010, 01:24 PM   #19
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

Here are back side pics of the boards and power board without the metal plate:

Again, here's the situation:
1) Connected monitor to known working computer
2) Turn on monitor
3) Power LED on front panel of monitor is Green
4) 'ACER' logo is displayed on the screen, then says 'NO SIGNAL'
5) Power LED on front panel of monitor turned Amber/Orange, and the screen goes black
Attached Images
File Type: jpg acer24-3 009.jpg (303.8 KB, 307 views)
File Type: jpg acer24-2 002.jpg (200.5 KB, 209 views)
File Type: jpg acer24-2 006.jpg (361.4 KB, 220 views)

Last edited by dt2rz; 10-26-2010 at 01:33 PM..
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Old 10-26-2010, 01:37 PM   #20
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Default Re: Acer AL2416 AL2416W 24" 1920x1280 LCD Monitor

It's hard to tell, but on the fourth photo (inverter) of your original set, it looks like the second cap above transformer T103 is domed. Also, the cap above to the left of IC2 might also be domed.
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