I'm trying to repair my Acer AL2416W B monitor

[countrydj]

Hi Guys..
I have an Acer AL2416W B monitor that is rather pooly.

First of all, the problem that I had was that I had to turn on my computer FIRST and then the monitor.
If I switched off the monitor, I had to disconnect the data lead until the indicator light turned AMBER and then reconnect.

Secondly, whilst watching the screen (I was on the telephone) the screen suddenly went BLACK at the left hand side and graduated to bright at the right hand side.

I have tried to repair it by replacing the known bad capacitors on the invertor board. I changed the top 4, which were clearly blown. The bottom 4 and the 2 others seemed OK.
However, this made no difference.
I have now changed the bottom 4 and the 2 others and this has made no difference.

Is it possibe that the FETs can cause this problem ?
If so, I will set about changing the FETs.
This means that I will have to remove the invertor board again to find the number on the FETs

Regards,

John C


Now for a question: How can I test the monitor, after a repair, without reassembling it completely, including putting the back back on.
I have seen video on Youtube showing a monitor working without the back on.

[mariushm]

Re: I'm trying to repair my Acer AL2416W B monitor

Check the soldering of the wires on the end of the lamps, make sure the wires are properly connected to the cfl lamps. you have to remove the shield on the back of the panel to do that.
DO NOT open it while plugged it, as you have 700v+ on the lamps.

If wires are loose, then one of them could turn off and the other lamp could take up the load and become very bright until the inverter can't keep up anymore.

Check the lamps and see if they got black at the ends (sign of going bad)

as for testing without closing it... usually people use a big desk and a mirror or something similar.

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

hi - Not sure what boards you have in this model. Are there some voltage regulators on the main board? Have you tested them?.
Welcome to the forum-
We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

[countrydj]

Re: I'm trying to repair my Acer AL2416W B monitor

Many thanks for quick replies...

If wires are loose, then one of them could turn off and the other lamp could take up the load and become very bright until the inverter can't keep up anymore.

Check the lamps and see if they got black at the ends (sign of going bad)

I will have a look at these, hopefully tomorrow.
I'm not quite sure where the lamps are. Can you give me a clue.
Presumably, there are lamps at each side of the screen.
Up to now, I've just taken the back off and the metal cover sheilding the pcbs.

as for testing without closing it... usually people use a big desk and a mirror or something similar.

I'm not worried about the size and seeing.
When I've plugged in the mains lead, the monitor will not switch on (no green indicator light) until I have fitted the back cover.
Am I missing something ???

Regards,

John c

[countrydj]

Re: I'm trying to repair my Acer AL2416W B monitor

A little bit 'off topic' but I am wondering:

mariushm
Badcaps Veteran

Join Date: May 2011
City & State: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hobbyist Tech
Posts: 1,078

and

selldoor
Slow Learner

Join Date: Dec 2010
City & State: Lancashire UK
Posts: 2,015

How can selldoor be a slow learner with 2015 posts, and mariushm be a Badcaps Veteran with only 1078 posts ????
Maybe it's because selldoor is from the same county as me ???
My trouble is that I'm a 'NON LEARNER'...

Regards,

John C

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

Its so that I can ask daft questions whenever I feel like it - eg why does it only work with the back on ( Only Joking.) I probably just have more time to spend on here and it saves me buying rubbish on ebay.You will soon be a learner -steep curve. I havent heard that one before tho the odd tv has a switch so it doesnt work when exposed to light.
Just check for micro switches

Was it this utube http://www.youtube.com/watch?v=Xm0AJ65TGOI

His mosfets or at least one had gone. Works with back off. As you're
a noobie I can ask if you had the cable pushed right in, plugged in and switched on at the mains : :

[countrydj]

Re: I'm trying to repair my Acer AL2416W B monitor

Was it this utube http://www.youtube.com/watch?v=Xm0AJ65TGOI

Yes. This was the best help to repair my monitor (up to now).

Its so that I can ask daft questions whenever I feel like it ......

As you're a noobie I can ask if you had the cable pushed right in, plugged in and switched on at the mains

I understand now.

NO. I'm joking...

Yes. I did have the cable pushed in properly, and it was disconnected from my spare monitor that I am using so it was plugged into the mains properly

As you don't know me, let me explain.
Back in the olden days, I was a fully qualified radio, television and electronics engineer, with City & Guilds final certificate plus colour thelevision endorsement.
I gave that up in the mid 1970's
I am now a computer engineer, qualified only by experience.

Back in the olden days, a 'proper' television engineer would repair a television down to component level.
Nowadays, the seem to swap panels and then send them away for repair.

I'm not a lot different with computers. It is easier and CHEAPER to 'throw away and replace'.
As a matter of fact, I can replace this monitor for around £112.00, but it is more interesting to try and repair it.

Regards,

John C

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

Ok - so are you getting some pictures for us? and did you look for anything that might be a tamper switch on the frame where the back goes on.

[countrydj]

Re: I'm trying to repair my Acer AL2416W B monitor

Hi Guys...

I have now stripped down the monitor again, and at each stage I plugged in the mains lead - and the power was on.
Maybe selldoor's suggestion that I didn't push the power cable far enough in was correct.
I told you that I am a NON LEARNER!!!

However, there is progress. Not good progress. When I switch on the monitor (before I stripped it down) the picture came on for about half a second and then went off. The dark right hand side was still evident.

I now have a couple of photos (if I can figure out how to attach them).
I have uploaded 2 pictures which I can see in the Attach Files section, but I don't know what to do now.
I will just Submit this post. If you can't see the attachments, maybe you can advise me what to do.
Now that I have just Previewed my post I can see the attachments.

On picture 009.jpg you will see that it is a block of 4 caps (which I have already changed) and 2 FETs.
I put an ohmeter across the 2 outer legs of 4 FETS and found that when I tested the RIGHT hand one of the 2 showing in the photo, it had a very low resistance (compared with the others).
The FET is a NIKOS P5504EDG.
The P5504 does not return any results on CPC web site.

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

Man - thats a terrible picture but your on the right track I will try and see what you can use instead - They are usually replaced in pairs are both/ all four the same part number.

[countrydj]

Re: I'm trying to repair my Acer AL2416W B monitor

Man - thats a terrible picture

I know. I'm going to learn how to use the camera. I've only had it about 12 months.

There are 2 x P5504EDG and 2 x P2804BDG

I think that CPC do a FDD4685 which is very similar to P5504EDG but I haven't found an equivalent for P2804BDG.
That Youtube video suggested FDD4685 but that is not in the CPC catalogue.

I think that I have seen some equivalents somewhere, but I can't remember where.

Am I right that the FET with the low resistance reading is faulty, or is it the other 3 ???

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

I came up with these pairs

FDD5614P and FDD5612.

FDD8451 and AOD413

Farnell have at least one of them but not cpc - typically

This is the test we recommend for mosfets its from retired caps guide
https://www.badcaps.net/forum/showthread.php?t=10419
Mosfets
---------

If you have a manual range multimeter, set it to 200 ohms (two hundred). You can test a mosfet (Q, IC designation) "in circuit" by (power off and unplugged)

a) black on pin 1- red on pin 2 - record ohms
b) black on pin 1- red on pin 3 - record ohms
c) black on pin 2- red on pin 3 - record ohms

If any ohm reading is less than 30 ohm you might have shorted mosfet. Remove from circuit and repeat the tests to verify.

Some mosfets are more than 3 pins. To test those, identify the part number and search for its datasheet. Once you find the datasheet, the pins will be designated source (S), gate (G), and drain (D). It will probably be documented as S1, S2, G1, G2, D1, D2.

Simply test

a) black on pin S1- red on pin G1 - record ohms
b) black on pin S1- red on pin D1 - record ohms
c) black on pin G1- red on pin D1 - record ohms

Repeat for the "2" pins. That is S2-G2, S2-D2, G2-D2.

Note: a shorted mosfet would likely cause a very brief flash of the backlight or no backlight.

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

I think that CPC do a FDD4685 which is very similar to P5504EDG but I haven't found an equivalent for P2804BDG.

That Youtube video suggested FDD4685 but that is not in the CPC catalogue.

Not sure if you have a number wrong here? I have done a comparison sheet of basic data and cpc stock 2 either of which I think would do. However the differences might be enough to cause an imbalance putting more pressure on other components.
What I would try (I have not tried it before) would be if you think a P5504EDG is failing or failed having done further tests, is buy just 1 from cpc and just try it to see if it improves, if it does then you could change the other/s so they match. I note the ones I found earlier that others had used were 60volt which might even be more robust but I dont know enough to be sure though.

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

Just looking at your poor pictures again and whilst I cant see them there are two fuses on the inverter board - have you checked them?
Meter on Ohms, probe on each end of fuse, should be almost the same as touching the probes together. Please quote numeric value rather than just saying its good.

[countrydj]

Re: I'm trying to repair my Acer AL2416W B monitor

Here are some better pictures, with some readings.
The first one is the whole board, pinched from the Internet somewhere.
The other 2 are clips from the first one, with added comments.

hth

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

Ok to look at web pics perhaps best not to post them as although you have
said its a copy people get confused and look for and find things on the pics that are not on your boards.
My guess is that caps deteriorated put pressure on the mosfet and when it
went (im pretty sure its dead) took out the fuse.
You can wait for other opinions see if any other suggestions then if nothing
buy the one at cpc - Its probably quite difficult to remove - may help to pre heat the whole area with a hairdryer to stop the board conducting all the heat away.

Any marking on fuse?

ebay have original mosfets - order now 20-25 days delivery

http://www.ebay.co.uk/itm/P5504EDG-P...item415dd70480

[countrydj]

Re: I'm trying to repair my Acer AL2416W B monitor

Ok to look at web pics perhaps best not to post them as although you have
said its a copy people get confused and look for and find things on the pics that are not on your boards.

It is an EXACT picture of mine.
I got the picture from:
http://www.ebay.com/itm/Acer-AL2416W...item2c677fdbff
There was no copyright notice attached to it, so it is fair game....

Any marking on fuse?

No. Only f2.

[selldoor]

Re: I'm trying to repair my Acer AL2416W B monitor

It is an EXACT picture of mine.

No it is not.

No. Only f2.

Should be ok with a 4A fastblow 32v.
If you dont like soldering smd parts, with a fuse you can just solder it on top of the old one.

[countrydj]

Re: I'm trying to repair my Acer AL2416W B monitor

No it is not.

OK. If you say so...