Badcaps.net Forum
Go Back   Badcaps Forums > Electronics Theory and Troubleshooting > Troubleshooting Computer Displays
Register FAQ Members List Social Groups Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 09-05-2010, 07:51 PM   #1
Borgleader
New Member
 
Join Date: Sep 2010
Posts: 8
Default Acer AL1916

Hi,

after reading a blog post I dug out my Acer AL1916 from my closet in hopes of possibly fixing it. The reason I had stopped using it in the first place is that one morning when I got up I tried to turn it on and neither the power LED or the screen itself would light up.

So like I said I dug it out plugged it in and no surprise here, nothing happened. Now I've already checked the capacitors and I believe all of them are in order, I didn't see any bulging near the top for those that had slits and for those that didn't I couldn't see any obvious bulging either.

Aside from that I have no clue. I am completely oblivious to anything electronic/electric which is why I came here (the bad capacitor suggestion was made by someone on another, more software oriented, forum).

http://www.mediafire.com/?v2a385jl9e05m

Here I uploaded pictures of the circuit boards inside the monitor. Also, I'm not sure if this can be of any help:
http://www.go-gddq.com/upload/2009_0...0313346662.pdf
It's an Acer Service Guide for this model (I assumed it was the right one, there are multiple variants of the AL1916 model but this particular guide was the only one to have pictures of the circuit board that matched mine).

P.S: This is probably not important but if I connect the monitor to my laptop's VGA port, the laptop's display flickers to a different resolution.

Last edited by Borgleader; 09-05-2010 at 07:58 PM..
Borgleader is offline   Reply With Quote
Old 09-05-2010, 08:29 PM   #2
PCBONEZ
Grumpy Old Fart
 
PCBONEZ's Avatar
 
Join Date: Aug 2005
City & State: Phoenix, AZ
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Professional Tech
Posts: 10,631
Default Re: Acer AL1916

Order replacements for the Elite.
If they aren't shot yet they will be soon enough.

Next check for a blown fuse on the yellowish PCB.
.
__________________
Mann-Made Global Warming.
- We should be more concerned about the Intellectual Climate.

-
Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

- Dr Seuss
-
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
-
PCBONEZ is offline   Reply With Quote
Old 09-05-2010, 10:04 PM   #3
Borgleader
New Member
 
Join Date: Sep 2010
Posts: 8
Default Re: Acer AL1916

Quote:
Originally Posted by PCBONEZ View Post
Order replacements for the Elite.
If they aren't shot yet they will be soon enough.

Next check for a blown fuse on the yellowish PCB.
.
I used the search function inside the service guide with "fuse" and it came up next to "F901", and if I look at the yellow board F901 is a little red box with 3 pins. I was expecting some sort of tube shaped component with one pin on each end.

Aside from that none of the components actually look damaged.
Borgleader is offline   Reply With Quote
Old 09-06-2010, 02:27 AM   #4
Rtech
Badcaps Veteran
 
Join Date: Jul 2010
City & State: Harrogate UK
Posts: 1,078
Default Re: Acer AL1916

'3' Pins ?????,should just have '2' !!!
If that is ok,then measure DC Volts acoss the big Brown capacitor,that should be 1.4 times your mains voltage, dependant on what country you are in ??.BEWARE Mains Voltage can be dangerous, so be VERY careful.
Rtech is offline   Reply With Quote
Old 09-06-2010, 05:29 AM   #5
PCBONEZ
Grumpy Old Fart
 
PCBONEZ's Avatar
 
Join Date: Aug 2005
City & State: Phoenix, AZ
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Professional Tech
Posts: 10,631
Default Re: Acer AL1916

F901 should only have two pins. [look at schematic]
Probably looks like a resistor.
.
PCBONEZ is offline   Reply With Quote
Old 09-06-2010, 06:01 AM   #6
sabre504
Badcaps Veteran
 
Join Date: May 2010
City & State: Cambridge (UK)
Posts: 399
Default Re: Acer AL1916

Hi which model of 1916 is this (widescreen or standard)
Only that i may have the correct pdf
sabre504 is offline   Reply With Quote
Old 09-06-2010, 07:50 AM   #7
Borgleader
New Member
 
Join Date: Sep 2010
Posts: 8
Default Re: Acer AL1916

Quote:
Originally Posted by Rtech View Post
'3' Pins ?????,should just have '2' !!!
If that is ok,then measure DC Volts acoss the big Brown capacitor,that should be 1.4 times your mains voltage, dependant on what country you are in ??.BEWARE Mains Voltage can be dangerous, so be VERY careful.
http://www.gbaudio.co.uk/data/mains.htm
Canada: 120V @60Hz
Voltage across the biggest of the capacitors is ~165V.


Quote:
Originally Posted by PCBONEZ View Post
F901 should only have two pins. [look at schematic]
Probably looks like a resistor.
.
It seems I was incorrect, when I looked at it last night the lighting was dim, so today I un-screwed the yellow board and flipped it over it only has 2 pins. Also, the markings on the box read "T2A" and "392". And it looks in good shape.
http://www.mediafire.com/imgbnc.php/...1abf703c6g.jpg
http://www.mediafire.com/imgbnc.php/...9c06cb206g.jpg
http://www.mediafire.com/imgbnc.php/...b6c9b00d6g.jpg

Quote:
Originally Posted by sabre504 View Post
Hi which model of 1916 is this (widescreen or standard)
Only that i may have the correct pdf
My model is AL1916AB, ration 4:3. I've taken a picture of the back sticker with P/N and all in case you need to know anything else. Like I said in the OP, out of the 4 service guides on the Acer website (e,p,v,W) the only one where the green circuit board was the same was the v (which I linked to).
http://www.mediafire.com/imgbnc.php/...8b72360c6g.jpg
Borgleader is offline   Reply With Quote
Old 09-06-2010, 08:51 AM   #8
smason
Badcaps Veteran
 
smason's Avatar
 
Join Date: Feb 2010
City & State: Alberta
My Country: Canada
Line Voltage: 120VAC 61Hz
I'm a: Hobbyist Tech
Posts: 1,589
Default Re: Acer AL1916

Looks in good shape, but did you measure it?
Looking isn't going to eb enough. You'll need to measure, or replace caps, and measure fuses and voltages to fix the problem.
__________________
36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....
smason is offline   Reply With Quote
Old 09-06-2010, 09:08 AM   #9
Borgleader
New Member
 
Join Date: Sep 2010
Posts: 8
Default Re: Acer AL1916

Quote:
Originally Posted by smason View Post
Looks in good shape, but did you measure it?
Looking isn't going to eb enough. You'll need to measure, or replace caps, and measure fuses and voltages to fix the problem.
As weird as it may be, the continuity test on my multimeter doesn't "beep", instead when I connect the two probes the value goes from 1. to ~0.

Since the fuse (red box) is soldered so close to the board, I can't test the two pins from the top, so I unscrewed the board again and put one probe on each of the two pins/metal patches on the bottom of the board and I got the same ~0.

This means it's good right?
Borgleader is offline   Reply With Quote
Old 09-06-2010, 10:31 AM   #10
retiredcaps
Badcaps Veteran
 
Join Date: Apr 2010
City & State: Canada
Posts: 8,350
Default Re: Acer AL1916

Quote:
Originally Posted by Borgleader View Post
As weird as it may be, the continuity test on my multimeter doesn't "beep", instead when I connect the two probes the value goes from 1. to ~0.

This means it's good right?
The threshold for continuity varies with multimeters. Some beep "good" if the resistance is less than 1.5k ohm.

A good fuse should read less than 1.0 ohms depending on the multimeter.

Since you measure 165V DC across the main filter capacitor that implies the main fuse is good.

The next step is to measure the secondary voltages between the logic board and power board. Use a ground screw for ground. You should see 5V DC and maybe 12V or 19V DC depending on the monitor.

If you don't, then post clear focused pictures of the backside. On the backside, there will likely be a 8 pin or 10 pin IC. We will need its part number.

BTW, pictures should be posted using the following method here.

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

Please do not post pictures inline as they slow down the loading of pages.
retiredcaps is online now   Reply With Quote
Old 09-06-2010, 12:18 PM   #11
Borgleader
New Member
 
Join Date: Sep 2010
Posts: 8
Default Re: Acer AL1916

(I had originally uploaded my pictures to mediafire to save bandwidth to the server, but since the guidelines suggest using attachments with a max width of 700px i resized it and attached it)

Ok so on this picture, the cables going off to the bottom right come from the yellow circuit board. I put the black probe on the ground screw under them (from this angle) and the red probe in a few of the sockets at the end of the cables.

I got readings of ~4.47V DC (for brown cable), and ~4.92V (for yellow & green cables). The others I couldn't get a reading, the metal part is just too far in.
Attached Images
File Type: jpg DSC_0024_2.jpg (657.4 KB, 49 views)
Borgleader is offline   Reply With Quote
Old 09-06-2010, 01:29 PM   #12
retiredcaps
Badcaps Veteran
 
Join Date: Apr 2010
City & State: Canada
Posts: 8,350
Default Re: Acer AL1916

Quote:
Originally Posted by Borgleader View Post
I got readings of ~4.47V DC (for brown cable), and ~4.92V (for yellow & green cables). The others I couldn't get a reading, the metal part is just too far in.
Look at page 32 of the PDF file in your first post.

It tells you to measure U701 and U702 for 3.3V. You should also be seeing 12V DC on pin 5 and 6 at CN701.

Your pictures of the power board at the offload site have too much glare for me to see the PCB designations. We want a picture that looks like this

http://www.badcaps.net/forum/attachm...7&d=1280167246
retiredcaps is online now   Reply With Quote
Old 09-06-2010, 01:47 PM   #13
retiredcaps
Badcaps Veteran
 
Join Date: Apr 2010
City & State: Canada
Posts: 8,350
Default Re: Acer AL1916

BTW, on page 45 of the PDF, it shows F902, a fuse.

If this F902 is open (you need to verify with a multimeter), then you will not get 12V DC.

Note the fuse might be on the backside of the board if it is not on the front.
retiredcaps is online now   Reply With Quote
Old 09-06-2010, 03:11 PM   #14
retiredcaps
Badcaps Veteran
 
Join Date: Apr 2010
City & State: Canada
Posts: 8,350
Default Re: Acer AL1916

If the fuse F902 is less than 1.0 ohms, then test diode D921.

Check the diode "in circuit" first. If the readings are suspicious, then you will have to remove it and retest.

If it is a dual diode, it should have two diode symbols pointing at each other towards the middle pin (pin 2).

Put your multimeter on 2000 ohms (if manual range) scale. With power off and lcd unplugged.

1) put red on pin 1, black on pin 2. report ohms.
2) put red on pin 3, black on pin 2. report ohms.
3) put red on pin 1, black on pin 3. report ohms.

Now switch to diode mode setting on your multimeter. With power off and lcd unplugged.

1) put red on pin 1, black on pin 2. report volts.
2) put black on pin 1, red on pin 2. report volts.
3) put red on pin 3, black on pin 2. report volts.
4) put black on pin 3, red on pin 2. report volts.

If the diode tests good, then I suggest measuring the voltage (power on) on pin 2 on the diode (put black on a ground screw). You should get 12V DC.

If you are not getting 12V DC, then either one of or all C923, C931, C925 (see schematic) is bad (as per PCBONEZ back in post #2). Even though they show no visible sign of distress, they can have high ESR (ohm) or be out of uF tolerance.
retiredcaps is online now   Reply With Quote
Old 09-06-2010, 08:38 PM   #15
Borgleader
New Member
 
Join Date: Sep 2010
Posts: 8
Default Re: Acer AL1916

Quote:
Originally Posted by retiredcaps View Post
Look at page 32 of the PDF file in your first post.

It tells you to measure U701 and U702 for 3.3V. You should also be seeing 12V DC on pin 5 and 6 at CN701.
I've added a new picture (in attachment) of the green circuit board. At U701 (top left), there isn't actually a component. It's been observed in another thread in this forum: http://www.badcaps.net/forum/showthread.php?t=8257

Even though there wasn't a component in U701, I checked the 3 spots where would've been soldered the pins had they been there (just in case it's helpful) and I also checked the 3 pins for U702. For each of these I used the top screw as my ground.

U701: Top pin: ~0V | Mid pin: ~0V | Bottom pin: ~4.92V
U702: Top pin: ~4.65V | Mid pin: ~3.3V | Bottom pin: ~0V
(Since top/bottom is relative, U701 is top left corner, Blue VGA port is bottom right)

As for CN701, pin 5 doesn't have a cable in it so I didn't manage to get a reading, but pin 6 had a reading of ~14.5V DC.

Quote:
Originally Posted by retiredcaps View Post
BTW, on page 45 of the PDF, it shows F902, a fuse.

If this F902 is open (you need to verify with a multimeter), then you will not get 12V DC.

Note the fuse might be on the backside of the board if it is not on the front.
The fuse is indeed on the backside, and again like F901, in the continuity test I got ~0 which is the silent equivalent of "beep".

Quote:
Originally Posted by retiredcaps View Post
If the fuse F902 is less than 1.0 ohms, then test diode D921.

Check the diode "in circuit" first. If the readings are suspicious, then you will have to remove it and retest.

If it is a dual diode, it should have two diode symbols pointing at each other towards the middle pin (pin 2).

Put your multimeter on 2000 ohms (if manual range) scale. With power off and lcd unplugged.
...

Now switch to diode mode setting on your multimeter. With power off and lcd unplugged.

...

If the diode tests good, then I suggest measuring the voltage (power on) on pin 2 on the diode (put black on a ground screw). You should get 12V DC.

If you are not getting 12V DC, then either one of or all C923, C931, C925 (see schematic) is bad (as per PCBONEZ back in post #2). Even though they show no visible sign of distress, they can have high ESR (ohm) or be out of uF tolerance.
F902 is ~0.3 ohms (I used a scale of 200, didn't have 20).

D921 (ohm scale 20k, 2k was not enough):
1) put red on pin 1, black on pin 2: 3.96k
2) put red on pin 3, black on pin 2: 3.92k
3) put red on pin 1, black on pin 3: 0k

D921 (diode test):
1) put red on pin 1, black on pin 2: 0.232
2) put black on pin 1, red on pin 2: 1. (the manual says to reverse the leads if i get this, which ends up being 1) )
3) put red on pin 3, black on pin 2: 0.231
4) put black on pin 3, red on pin 2: 1.

Sorry for the delay, I have to pretty much google everything because I've never had to do this before.
Attached Images
File Type: jpg DSC_0051.jpg (441.6 KB, 19 views)
File Type: jpg DSC_0046_2.jpg (511.6 KB, 38 views)

Last edited by Borgleader; 09-06-2010 at 08:40 PM..
Borgleader is offline   Reply With Quote
Old 09-06-2010, 09:44 PM   #16
retiredcaps
Badcaps Veteran
 
Join Date: Apr 2010
City & State: Canada
Posts: 8,350
Default Re: Acer AL1916

Quote:
Originally Posted by Borgleader View Post
As for CN701, pin 5 doesn't have a cable in it so I didn't manage to get a reading, but pin 6 had a reading of ~14.5V DC.
Hmm, that voltage looks a bit high. It should be 12V DC.

Quote:
F902 is ~0.3 ohms (I used a scale of 200, didn't have 20).

D921 (ohm scale 20k, 2k was not enough):
1) put red on pin 1, black on pin 2: 3.96k
2) put red on pin 3, black on pin 2: 3.92k
3) put red on pin 1, black on pin 3: 0k

D921 (diode test):
1) put red on pin 1, black on pin 2: 0.232
2) put black on pin 1, red on pin 2: 1. (the manual says to reverse the leads if i get this, which ends up being 1) )
3) put red on pin 3, black on pin 2: 0.231
4) put black on pin 3, red on pin 2: 1.
F902 and D921 test good.

Let's try measuring the voltage on D921 pin 2 (middle pin). Put your black probe on the ground screw in the top left. Red on pin 2. Report the DC V measurement.

Hmm, I will have to think about this. You are getting 5V DC and 14.5V DC, but there is no power LED.
retiredcaps is online now   Reply With Quote
Old 09-06-2010, 09:58 PM   #17
retiredcaps
Badcaps Veteran
 
Join Date: Apr 2010
City & State: Canada
Posts: 8,350
Default Re: Acer AL1916

I just started reading the other thread it looks like 14.5V DC ish is correct. So nix the measurement on the D921.

edit: okay, you may want to read about U406 as per PlainBill's posts.

Last edited by retiredcaps; 09-06-2010 at 10:08 PM..
retiredcaps is online now   Reply With Quote
Old 09-10-2010, 03:21 PM   #18
Borgleader
New Member
 
Join Date: Sep 2010
Posts: 8
Default Re: Acer AL1916

Quote:
Originally Posted by retiredcaps View Post
I just started reading the other thread it looks like 14.5V DC ish is correct. So nix the measurement on the D921.

edit: okay, you may want to read about U406 as per PlainBill's posts.
Sorry for the delay, just got back to Uni and haven't got used to my schedule yet.

Ok so I Ctrl+F U406, and I took the same measurements that PlainBill asked for in the other thread, and I got the same results, that is:
Left pin: 0.00V
Middle pin: 4.92V
Right pin: 4.30V

And so I proceeded with his test (unlike the other poster I chose the battery version). And I got:
Top pin: 0.4V & 0.01V (We werent able to repeat the 0.04V however, so it could be a fluke)
Right pin: 0.05V

I cant deduce anything from his post however since he assumed that the top pin would have 3V on it, although the fact that it doesnt may mean the part is bad, or maybe the soldering gave out?
Borgleader is offline   Reply With Quote
Old 09-10-2010, 04:26 PM   #19
retiredcaps
Badcaps Veteran
 
Join Date: Apr 2010
City & State: Canada
Posts: 8,350
Default Re: Acer AL1916

Quote:
Originally Posted by Borgleader View Post
And so I proceeded with his test (unlike the other poster I chose the battery version). And I got:
Top pin: 0.4V & 0.01V (We werent able to repeat the 0.04V however, so it could be a fluke)
Right pin: 0.05V
I suggest retesting this again. Please try to use the same terminology as in PlainBill's post so it makes it easier for us to track and read.

If you are not getting 3V on the upper pin, that means something is wrong.
retiredcaps is online now   Reply With Quote
Old 09-10-2010, 04:32 PM   #20
jetadm123
Badcaps Veteran
 
Join Date: Feb 2010
City & State: California
Posts: 1,832
Default Re: Acer AL1916

Quote:
Originally Posted by Borgleader View Post
Sorry for the delay, just got back to Uni and haven't got used to my schedule yet.

Ok so I Ctrl+F U406, and I took the same measurements that PlainBill asked for in the other thread, and I got the same results, that is:
Left pin: 0.00V
Middle pin: 4.92V
Right pin: 4.30V

And so I proceeded with his test (unlike the other poster I chose the battery version). And I got:
Top pin: 0.4V & 0.01V (We werent able to repeat the 0.04V however, so it could be a fluke)
Right pin: 0.05V

I cant deduce anything from his post however since he assumed that the top pin would have 3V on it, although the fact that it doesnt may mean the part is bad, or maybe the soldering gave out?
If you read the entire thread, the second test suggests shorting the bottom 2 pins with a small screwdriver, while hitting the power button. This sets the reset pin to zero (ground). Some people actually removed U406 altogether (I don't recommend this). Read the entire thread and decide for yourself.
jetadm123 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 08:11 PM.


Badcaps.net Technical Forums 2003 - 2014
Powered by vBulletin ®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.

Did you find this forum helpful?