Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashlight

[Peale]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Oh, F200 is good, also.

[Peale]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

1) that was one of the first things that I resoldered (everything that you circled in yellow). You're right - photos lie.

2) F102 is good.

3) S1 --> S2 = .748, S3 --> S4 = .746. So, that means 748 Ohms and 746 Ohms, respectively.

[selldoor]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Ok I have marked a number of things on the board that may help.

1 The yellow ringed joints "look" a bit odd (it may just be the light or the picture - they often lie) Can you check with a magnifier and if they look bad to you resolder them.
Recommend adding a bit of new solder removing it all and resoldering.

2 I have marked in magenta? a fuse Can you test it.
There may be more but my eyes are tired.

3 S1 -4 are I think the secondary windings on the Inverter transformer. Power OFF - meter on ohms 2000 - test S1>S2 and S3>S4 and post the results.

[Peale]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Absolutely! Let me know if these don't work.

[selldoor]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Could be
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 (in the same orientation) 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...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

[Peale]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Replaced the capacitor as mentioned above, no change.

I started to think about it, a bit. I unplugged the leads for one of the florescent bulbs, and powered it up...and it came up. For a second.

Tried the same with the other pair...same thing.

Does that mean that the...I think it's called an "inverter...is bad?

Revisiting this. Is there a way that I can test this component? Or, am I barking up the wrong tree? This was working, after the recap, until it wasn't.

[Peale]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Replaced the capacitor as mentioned above, no change.

I started to think about it, a bit. I unplugged the leads for one of the florescent bulbs, and powered it up...and it came up. For a second.

Tried the same with the other pair...same thing.

Does that mean that the...I think it's called an "inverter...is bad?

[Peale]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

I'm guessing a problem with the mosfets (they're not reading as shorted, but one definitely has different readings than the other). I'd order a couple from Mouser (along with the proper fuses) but it seems that Mouser doesn't carry them, unless I'm missing something.

Found them on eBay. Replaced them, the monitor fired right up.

Left it running; came back, it was dead, again.



Shut it down, waited a few seconds, plugged it back in, and it came up. Walked away, came back...dead again.

Did that at least once more, and now it won't come up, at all.

Fuse F200 isn't blown. Resoldered every torroid, transformers and inverters to no avail.

Still haven't replaced that one cap (the 2200uf that I referenced, above). Will advise when I do.

[Peale]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Just picked up one of these from a free pile.

All the 220uf caps were swollen. Replaced all electrolytic caps except the 120uf @ 400v and the 2200uf cap (and didn't replace that one because I didn't have one on-hand).

Found that F200 is blown. Not having one on hand, I put in a regular fuse in the interim, so I could keep testing. I've been using a fast blow, but should I use a slo-blow instead? It blows immediately.

I'm guessing a problem with the mosfets (they're not reading as shorted, but one definitely has different readings than the other). I'd order a couple from Mouser (along with the proper fuses) but it seems that Mouser doesn't carry them, unless I'm missing something.

[darioj]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Please use the manage attachments button to post your pictures and please do not post inline.

yes,sorry I know not how to do!

[retiredcaps]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Photos are not mine,.

That is exactly the point. We need photos of YOUR boards. Manufacturers make revisions all the time to the board internals, but keep the exact same lcd model number.

In addition YOUR board may contain nuances that we can spot (like a hot area, burned resistor, dodgy component, etc).

Please use the manage attachments button to post your pictures and please do not post inline.

[darioj]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

Photos are not mine, but the board are the same as mine.Photos are 1550x1397, and logic is 800x600.for me do not seem too small!
I certainly understand that you do not repair a circuit looking at the picture!
I would just like an idea,What I can measure or what i can replace.

[PlainBill]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

So if the drive works well, is the logic wrong? I remind you that the status LED is always orange, and the power button does not work.
You said:"The logic card does not use the 13.8 volt supply."
did you see in the photo that the pin 13 of the inverter goes the 13.8 vcc
to logicboard?why ?
excuse my many questions: I try to understand.
ultimately:you think that I must replace the logicboard or what?

I can't see anything useful in the photos!!! One is obviously NOT from your monitor. Both are too small to see much. And on the power supply / inverter you didn't provide a picture of the bottom of the board, and the legend is obscured.

Most monitors use the 13V output of the power supply only for the inverter. In those cases it goes to the logic board it is usually used only to power the LCD panel. The logic board itself has LDO regulators to provide the voltage the ICs require.

PlainBill

[darioj]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

So if the drive works well, is the logic wrong? I remind you that the status LED is always orange, and the power button does not work.
You said:"The logic card does not use the 13.8 volt supply."
did you see in the photo that the pin 13 of the inverter goes the 13.8 vcc
to logicboard?why ?
excuse my many questions: I try to understand.
ultimately:you think that I must replace the logicboard or what?

[PlainBill]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

yes,the problem is not the fuses,why the problem is not the absence of tension, in fact I find more tension than normal!what I want to understand: it is the higher tension that inhibits proper logicboard or the logicboard is gone?
and also: because I find tension higher than normal?
sorry, I hope I explained the concept.

The power supply regulates only the 5 volt output. It is designed so under normal load (backlights on), the other output is at 13.8 volts. If the backlights are not on, the 13.8 volt output will be at a higher voltage.

This is not the cause of the problem. The logic card does not use the 13.8 volt supply.

PlainBill

[darioj]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

yes,the problem is not the fuses,why the problem is not the absence of tension, in fact I find more tension than normal!what I want to understand: it is the higher tension that inhibits proper logicboard or the logicboard is gone?
and also: because I find tension higher than normal?
sorry, I hope I explained the concept.

[alexanna]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

If the backlights are not on you are not under alot of load.
There are very small surface mount fuses on the back side of the power supply,have you checked them?

[darioj]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

hi,
These are photos of the inverter and logic board.i asked to myself why i found
15,3vcc with no load,and 16,8 with logicboard connected:i should found 13,8 !
maybe it is corrupted the logicboard? or voltage is too high for its smooth operation?

[PlainBill]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

hello,
this is very interesting forum.
I also have a problem with this inverter:
monitor is dark, LED always orange and power button not risponding.i replaced the two MOSFETs and two capacitors which were bulging (C204, CE101), but the situation as not changed:the problem is not resolved.i measured output voltages:
I have the 5Vcc, but instead the 13.8 vcc i find
15.3 vcc, why this? You think that I must replace the logic board?
wait an help .thanks in advance and sorry for my bad english.

The 13.8 V output is high because only the 5V output is regulated. With no load on the 13.8 V supply the output will be a little high.

Pictures of the signal card would be useful. Some of them have a defective reset controller; other times we see a bad LDO regulator.

There is nothing seriously wrong with your English. You could pass as a product of the American educational system.

PlainBill

[darioj]

Re: Acer AL1916W Ab Monitor, DAC-19M008 - No Backlight, Recapped, Can see with Flashl

hello,
this is very interesting forum.
I also have a problem with this inverter:
monitor is dark, LED always orange and power button not risponding.i replaced the two MOSFETs and two capacitors which were bulging (C204, CE101), but the situation as not changed:the problem is not resolved.i measured output voltages:
I have the 5Vcc, but instead the 13.8 vcc i find
15.3 vcc, why this? You think that I must replace the logic board?
wait an help .thanks in advance and sorry for my bad english.