Acer AL2216W / DAC-19M009 dead?

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

U7 gives me 13 Ohms on middle pin vs. ground from the VGA connector, close enough to zero? =(

[jetadm123]

Re: Acer AL2216W / DAC-19M009 dead?

Well, the regulator could be internally shorted to ground. The only real way to test would be to remove U7 from the board and measure the middle pad to ground. Once off, you can also try testing U7 with a 9V battery. Apply the 9V to the input and measure the output with your meter. However, without a load on the regulator, there's potential for a false reading. Of course, if you read a zero volt output, then you know it's bad for sure.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

Okay, i'll try it tomorrow. Thank you so far

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

Looks like Jetadm is leading you to the right path to find the problem. If you remove the regulator and the low resistance reading is still there, then you can possible have bad MLCC , there are 5 of them that are connected to the regulator output pin, they tend to fail shorted out.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

I just unsoldered the regulator. Its resistance values are:

GND/ADJ - OUT: 338 Ohms
GND/ADJ - IN: 1810 Ohms
IN - OUT: 1491 Ohms

Looks fine so far, I guess.

I measured the caps you marked on the picture. I unsoldered one side of each one and measured eachs resistance, all infinte -> caps are fine too?

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

Are these the value measure at the pads on the board without the regulaor or the measurement made on the regulator itself?
The resistance we are interested in is the OUT pin pad and Ground pad reading.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

Values are from the regulator itself. So I have to unsolder it again and measure between the connectors on the circuit board?

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

We need to find out where the 13 Ohms reading on the OUT pin is from.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

Ah okay. I unsoldered it and it gives me the 13 Ohms between GND/ADJ- and OUT-pad.

Following the conducting path near the left cap you marked me (red) led me to the blue marked component. Ohm-meter gives me 13 Ohms between both pins and 0 Ohms between bottom pin and ground of the DVI-connector. The brown color implies that component being burnt, especially because its nearby "friends" are all black. What kind is it? It says "Z6" on circuit board and C2 (or 02?) on the component itself.

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

OK, you found it! Those are protection diodes for the Video dvi input signal, you can remove the burnt one out and see if the 13 Ohms goes away. They are use for the surge and spike protection for the DVI, there should be similar setup for the VGA input also.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

I removed the burnt one and reassembled the monitor as far as needed to test if it works now.
Plugged it in -> no LED, no starting possible.
I measured the Voltage of top 2 pins from the PSU: 1.11V giving me 1.27V on the circuit where the sources of the LED-MOSFETs and the OUT-pin of the regulator are in. Any new ideas? :/

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

Ok , so the 13 Ohms is no longer there? And unless I read it wrong, what voltage do you get now at the Out put of the regulator, it should be 3.3V as Jetadm had indicated.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

13 Ohms gone, 338 Ohms now (guess from the regulator OUT-GND).
The voltage is the 1.27V I mentioned above (remeasure gave me 1.35V now), thats the circuit in which the sources of the status LED controllers are.

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

From the thread, it is indicated that this is a 3.3V regulator, same as the other one on this board, both of them has the same number printed on them, right? If that is the case, this one should also put out 3.3v, it could be damaged due to that 13 OHMS load. You were getting less than 0.5V before you found that shorted component.

[selldoor]

Re: Acer AL2216W / DAC-19M009 dead?

Did you test the regulator with the 9 volt battery? - post 22

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

Yes, i just did. New 9V battery (delivered 9.6V) attached to the regulator gave me 3.6V from OUT-pin.

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

The ADJ pin connected to the Negative of the batteries, and put a 100 Ohms resistor between Out pin and negative of the batteries, then check the output reading again.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

Guess i just wrecked it. Shortened OUT and GND with my multimeter tip, 0V OUT since then.

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

I still think this regulator is already bad, I would just get another one.
By the way, when you were measuing 3.6V at the output pin, was the AGJ pin connected to the negative of the batteries, if not, that may explain why you are getting 3.6 instead of 3.3V

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

I'll order some new, hope they will be delivered on saturday and 0.29€/pc is a good price

I checked the voltage of the battery with my multimeter, positive 9.6V were shown, so I put the GND/ADJ pin to the battery terminal where the black tip was while measuring the voltage.