Acer AL2216W / DAC-19M009 dead?

[hitz]

Hello!

I've got a serious problem with my Acer AL2216W. It started with the orange stand-by LED getting darker a few weeks ago. Until yesterday there was no problem except the LED, the monitor was working fine. So yesterday i turned it off and when i came back, the orange LED was off and the monitor didn't start at all.
I opened it and checked the caps (had to change them a few years ago) two 1000μF were bulged. Today I replaced them with some of the same local shop, re-assembled the monitor, but no orange LED, no starting

So I plugged it in and checked the outgoing voltages:
13.8V pin was about 14.3V (a little high?)
5V pin was exactly 5V

Back to checking parts: The power switch and LEDs were fine, so I followed up the conducting path from the LEDs on the switch circuit board to the MOSFETs (K84 T9) and measured the voltage of the pins to case-ground:

green LED (power on):
Gate: 3.26V
Source: 0.16V
Drain: 0V

orange LED (stand-by):
Gate: 3.26V
Source: 0.16V
Drain: 0V

I checked the MOSFETs with the diode-check of my multimeter when the PSU was off, both gave me same values for the different measuring options (G-S, G-D, whatever).

So I followed the MOSFET's source circuit track to the PSU-connector. Its taken from a circuit between the top two pins (8 & 16) - voltage between them: 0.16V

The voltage seems a bit low to me, but following the pin conducting paths didn't lead me to any new idea. At this point I'm out of knowledge, so please help me!

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

"I checked the MOSFETs with the diode-check of my multimeter when the PSU was off, both gave me same values for the different measuring options (G-S, G-D, whatever)."
So what is the reading?
And "whatever" what does that mean?

Use Ohm mode and check S-D, S-G, D-G and tell use what the readings are, also tell us what ohm scale you are using, when look for short, I use 200 Ohms first then go lower scale from there.
Also check the fuses:
https://www.badcaps.net/forum/showth...ght=DAC+19M009

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

"I checked the MOSFETs with the diode-check of my multimeter when the PSU was off, both gave me same values for the different measuring options (G-S, G-D, whatever)."
So what is the reading?
And "whatever" what does that mean?

Didn't know the exact combinations I measured, but those combinations gave me nearly same values for both MOSFETs.

The Ohm-mode shows only a "1" in first position on the display, but in diode-check mode it shows following values (guessing its Ohms cause values for resistors were the same in Ohm-mode an diode-mode):
(left: black tip - right: red tip)
orange LED's MOSFET:
S-D: (starting with 752, slowly decreasing to) 684 Ohms
G-S: 1247 Ohms
G-D: 1806 Ohms

green LED's MOSFET:
S-D: (starting with 750, slowly decreasing to) 688 Ohms
G-S: 1248 Ohms
G-D: 1820 Ohms

Also check the fuses:
https://www.badcaps.net/forum/showth...ght=DAC+19M009

Fuses are fine (F102, F200, the one near AC connector and F1 near 16-pin connector on the smaller circuit board).

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

"green LED (power on):
Gate: 3.26V
Source: 0.16V
Drain: 0V

orange LED (stand-by):
Gate: 3.26V
Source: 0.16V
Drain: 0V"
Th voltage reading you are showing indicated that you are not getting the DC voltage feeding the MOSFET. What DC voltage do you get on that axial glass fuse, that fuse feeds the 14vdc fo powering the inverter circuits.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

What DC voltage do you get on that axial glass fuse, that fuse feeds the 14vdc fo powering the inverter circuits.

Its 23.2V

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

Please see pictures, you need to check the DC for the inverter again.
OK, your earlier post are not the same MOSFET I had in mind, the MOSFET'S are the 8-pin dip on the power supply-inverter board

[selldoor]

Re: Acer AL2216W / DAC-19M009 dead?

Its 23.2V

Was your meter on vDC?

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

Or at the right ground point?

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

I hold the black tip onto a screw attached to the monitor case. 23.2VDC, controlled it. The P605 Ohm-values are for both MOSFETS the same, as u can see on the picture i attached. The 3rd pin shows only shortly a value ~1700Ohms but then goes to unmeasurable.

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

"P605 Ohm-values are for both MOSFETS " What is the P605 Ohms?
There are 4 MOSFET's 8-PIN DIP that I redlined and I need the resistance reading of ALL FOUR MOSFET's.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

I've only 2 on my board, both got the values you can see on the picture i attached to my previous posting.

[budm]

Re: Acer AL2216W / DAC-19M009 dead?

OK, I see and understand your answer now. Sorry about the confusion.

[jetadm123]

Re: Acer AL2216W / DAC-19M009 dead?

If I correctly understood your testing of the AOP605, you tested S-D and G-D, but not S-G. You can test S-G by measuring across pins 1-2 and 3-4 of both AOP605.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

Oh yes, I missed that.

Pins: Top/Bottom MOSFET
1-2: 284 Ohms / 282 Ohms
3-4: 740 Ohms / 741 Ohms

[jetadm123]

Re: Acer AL2216W / DAC-19M009 dead?

Try checking fuse F1 (to the right of the black 16 pin connector) on the main/logic board.

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

Fuses are fine (F102, F200, the one near AC connector and F1 near 16-pin connector on the smaller circuit board).

[jetadm123]

Re: Acer AL2216W / DAC-19M009 dead?

Oops! Missed the earlier post about F1. Since you're not getting a power led, but good output voltages, possibly something wrong with the main board. There appears to be two voltage regulators on the main board U7 and U4? (upper right corner). Reconnect the power board to the main board and measure the voltage at each pin of U7 and U4. Also, what are the part numbers of U7 and U4?

[hitz]

Re: Acer AL2216W / DAC-19M009 dead?

Its U7 in the middle and U6 in upper right corner. Both are labeled 50117K-G.
The middle pin of U7 is directly connected to the source pins of both LED-MOSFETs I mentioned earlier.
For measured voltages open the attached picture.

[jetadm123]

Re: Acer AL2216W / DAC-19M009 dead?

It looks like U7 may be bad. We also want to make sure the output of the middle pin of U7 is not shorted to ground. To verify, unplug your monitor from power. With your meter set to 200 ohms, place one probe on the middle pin and the other probe to a ground point. Hopefully, you won't read zero ohms.

I'm thinking the regulators are part of the 1117 family of regulators.

[jetadm123]

Re: Acer AL2216W / DAC-19M009 dead?

If you look at the link below, post #5, you will see that a Viewsonic VX2235 uses the same mainboard as your Acer. And the output for both regulators should be 3.3V. If U7 passes the ground test, you should be able to use a 1117-33 regulator as a replacement.

https://www.badcaps.net/forum/showth...light=50117K-G