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Old 03-02-2009, 07:07 PM   #1
shimjocky
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Default The infamous 2 seconds to black

Just found this site yesterday. I think its great that you have a community willing to help noobies like myself who are just handy enough to be dangerous and not smart enough to walk away.

I have an Acer AL2223W. It has the symptom of blacking out seconds after being turned on. I have been wanting to learn to work on these things so I decided to tear into it.

After doing some reading here I decided to do what I could to troubleshoot the power supply. I was able to bench test it and with my multimeter I found that it was putting out the proper +12V and +5.2V. I then rigged it into my psu tester to try and put it under a load. What I found was that when I did this the +12V dropped to about 10.7V while the 5.2 stayed strong.

Two of the caps on the board look like they are trying to bulge. They are the type with a + scribed in the top. The quadrants of the + have bulged up a bit I think but not like I expected to find. These caps are very close to the output of the power supply.

Could the voltage drop under load possibly be why this monitor fires up then fails?

I wish I could take a pic but I am waiting for my batts for the camera to charge. Will follow up with a pic if needed.

Thanks for any help you can offer and thanks again for running such a great site.
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Old 03-02-2009, 07:25 PM   #2
NxB
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Default Re: The infamous 2 seconds to black

Just replace the caps and see. They could look fine and still be bad. Unless you have an ESR meter you won't know.
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Old 03-02-2009, 10:36 PM   #3
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Post Re: The infamous 2 seconds to black

Pics help, but if you put something like "I have 2 SamXon GL 2200uf 25v 105c on...."..." and 2 CapXon" well....., you get the idea. Brand,series, capacitance and V rating.
And yes, those fat caps can cause that, but you couldn't tell for sure until you change these (and maybe others, that's why the data or the pictures help).
And welcome to the forums.
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Old 03-03-2009, 06:23 PM   #4
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Default Re: The infamous 2 seconds to black

Here are the pics I just took. Will follow up with info from the caps. Sorry in advance to anyone with a smaller res but I am not sure how to thumbnail these darn photobucket images and your attachment manager is throwing db errors so I couldn't do it that way.







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Old 03-03-2009, 06:33 PM   #5
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Default Re: The infamous 2 seconds to black

Ok, now for the info on the caps. Damn those things can be hard to read!

one Capxon 25V 220uF KF105C C717

one Capxon 25V 220uF KF105C C718

two Taicon 25V 680uF 0715(M) 105C(HH)P

two Taicon 10V 1000uF 0715(M) 105C(HW)P

one Taicon 50V 22uF 0715(M) 105C(HW)P

P.S. Not sure of the values on the big cap as they are obscured by the goo.

Last edited by shimjocky; 03-03-2009 at 06:41 PM..
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Old 03-03-2009, 06:47 PM   #6
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Post Re: The infamous 2 seconds to black

Quote:
Originally Posted by shimjocky
Ok, now for the info on the caps. Damn those things can be hard to read!

Capxon 25V 220uF KF105C C717

Capxon 25V 220uF KF105C C718

Taicon 25V 680uF 0715(M) 105C(HH)P

Taicon 10V 1000uF 0715(M) 105C(HW)P

Taicon 50V 22uF 0715(M) 105C(HW)P
Change the 25v 680uf and 220uf - in fact all, but those first. They look OK with the naked eye, but sometimes they fail without visual indication.
Also, I have some questions:
  • When the lamps turn on, did you notice a reddish/pink hue in the light, or they light OK but shut down seconds after? You may have bad lamps on that one.
  • The 50v 22uf is near the transformer? you didn't put the C### marking like in the first two.
  • Do you notice any sound when the lamps go off?

With the specs you specified, in no time someone will be telling you the recommended replacement caps.Just wait, and see ...
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Old 03-03-2009, 07:08 PM   #7
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Default Re: The infamous 2 seconds to black

Thanks for the reply.

I have only looked at it during the post screen but I saw no strange colors. You see the acer logo then the actual post screen for about a second then it shuts down.

I just took another look at the caps and I am pretty sure I gave everything there was to be had.

I don't think I recall hearing anything strange when it shuts down

I added a crappy little arrow to point to the cap that I had said I thought was bulging. Kinda hard to tell in the pic, maybe due to the flash.

Last edited by shimjocky; 03-03-2009 at 07:13 PM..
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Old 03-04-2009, 04:17 AM   #8
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Default Re: The infamous 2 seconds to black

Also check out those 2 black rectangle box shape things, next to that cap you arrowed off, they look like fuses to me
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Old 03-05-2009, 05:11 AM   #9
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Default Re: The infamous 2 seconds to black

I think I will recap the whole psu at this point as it seems worth a try given the fairly low cost of doing so. If someone wouldn't mind recommending top shelf replacements for my caps I would be very grateful.
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Old 03-05-2009, 07:05 PM   #10
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Default Re: The infamous 2 seconds to black

Decided to try and figure out some replacements on my own. Here is what I am thinking so far. Please feel free to step in if you feel I have made an error in my choices. These are all Panasonic FC Series caps.

Capxon 25V 220uF KF105C C717
AND
Capxon 25V 220uF KF105C C718
Replacement
Panasonic EEUFC1E221
http://search.digikey.com/scripts/Dk...name=P10271-ND



Taicon 25V 680uF 0715(M) 105C(HH)P
Replacement
Panasonic EEUFC1E681
http://search.digikey.com/scripts/Dk...name=P10277-ND



Taicon 10V 1000uF 0715(M) 105C(HW)P
Replacement
Panasonic EEUFC1A102
http://search.digikey.com/scripts/Dk...name=P10225-ND


Taicon 50V 22uF 0715(M) 105C(HW)P
Replacement
Panasonic EEUFC1H220
http://search.digikey.com/scripts/Dk...name=P10318-ND

That just leaves the big cap. Do I need to worry about that one? If so how the heck do you break it loose from all the goo? I was just trying and it felt like I was gonna break the board.
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Old 03-05-2009, 07:07 PM   #11
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Default Re: The infamous 2 seconds to black

Quote:
Originally Posted by shimjocky
That just leaves the big cap. Do I need to worry about that one? If so how the heck do you break it loose from all the goo? I was just trying and it felt like I was gonna break the board.
Leave the big boy alone. They rarely fail, or so I've heard.
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Old 03-05-2009, 07:10 PM   #12
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Default Re: The infamous 2 seconds to black

Quote:
Originally Posted by eguevarae
Leave the big boy alone. They rarely fail, or so I've heard.
Thanks, will do.
How bout the FC series for power supplies, any good? I know this site recommends them for mobo's.
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Old 03-06-2009, 12:21 AM   #13
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Default Re: The infamous 2 seconds to black

When I'm ordering from DigiKey, I always order Panasonic FMs if the value I need is available in that series. They are better spec, and sometimes they are also cheaper than FC.
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Old 03-11-2009, 02:39 PM   #14
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Default Re: The infamous 2 seconds to black

Back again.

I got my caps today and did the power supply/inverter. I fired it up and I have the same problem as before. Well, actually the problem is worse now.

At one point before recapping I reassembled the monitor to do the flashlight test. I could see the faint pic so I know that part is working. Problem is that instead of the backlights coming on for a couple seconds they did not come on at all. The symptom is still the same after recapping.

I decided to tear it down further to look at the lamps. Boy I almost wish I hadn't! These things are a mess to take apart and I just hope I can remember how to get it back together again.

Anyhoo, since I have it apart what can I do to check the lamps? I honestly don't know what to look for. Also, is there a way I can test the inverter side of the power supply?

Thanks again for the advice thus far. I am learning a lot and having fun doing the work so keep it comin!
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Old 03-11-2009, 03:14 PM   #15
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Post Re: The infamous 2 seconds to black

Repost a clearer picture of the underside of the board to see if there's a SMD fuse to check. It was a problem with two Westinghouse units that have been discussed recently.

Last edited by EGuevarae; 03-11-2009 at 03:16 PM..
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Old 03-11-2009, 05:28 PM   #16
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Default Re: The infamous 2 seconds to black

Here is my latest round of pics. Still can't seem to upload to the forums here even though they are within the rules for size, keep getting database errors,ugh.

Took several pics of both sides with no flash so hopefully they will be helpful.















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Old 03-11-2009, 06:11 PM   #17
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Default Re: The infamous 2 seconds to black

See the marked components? those are jumpers. There may be a fuse around that area, as I can't locate any on the other side of the board.

What are the markings/part number on those two Q's?

Do you have any voltage reading AFTER the caps (like in the inverter's transformer)?
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Old 03-11-2009, 06:14 PM   #18
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Question Re: The infamous 2 seconds to black

Quote:
Originally Posted by shimjocky
After doing some reading here I decided to do what I could to troubleshoot the power supply. I was able to bench test it and with my multimeter I found that it was putting out the proper +12V and +5.2V. I then rigged it into my psu tester to try and put it under a load. What I found was that when I did this the +12V dropped to about 10.7V while the 5.2 stayed strong.

Could the voltage drop under load possibly be why this monitor fires up then fails?.
Did you re test it after the recap?
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Old 03-11-2009, 06:49 PM   #19
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Default Re: The infamous 2 seconds to black

Cant seem to get the same results with my psu tester as I did last time, not sure why, maybe my tester is broke. I am checking voltage at the output to the vid board and its showing good there but then it did before too.

I wouldnt know a fuse on the bottom if it bit me in the ass,lol. I did look at your latest pic in the westinghouse thread and made the assumption that a small fuse would be labeled with an F, if so I found none.

Q's???
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Old 03-11-2009, 07:04 PM   #20
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Default Re: The infamous 2 seconds to black

Quote:
Originally Posted by shimjocky
Cant seem to get the same results with my psu tester as I did last time, not sure why, maybe my tester is broke. I am checking voltage at the output to the vid board and its showing good there but then it did before too.

I wouldnt know a fuse on the bottom if it bit me in the ass,lol. I did look at your latest pic in the westinghouse thread and made the assumption that a small fuse would be labeled with an F, if so I found none.

Q's???
Transistors.
R = Resistor
F = Fuse
TH = Thermistor
D = Diode
Q = Transistor <---------------- I don't know why Q, because as you can see we had a pattern here until mr. Q arrived

If you can post the number on them (and if you can read voltage on them). And you are right. F is what you'll be looking for. I found none, either on the top side or the bottom.
Do you have voltage reaching the transformer ("T")?
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