Acer AL2416W Power supply problem

[budm]

Re: Acer AL2416W Power supply problem

What is P/N on that PFC IC1 in picture #3? Check D1, R4, Q4 which drive the Gate of MOSFET for the PFC. Also check PFC diode D13. R49 is the Source resistor for Q3.

[lele.v]

Re: Acer AL2416W Power supply problem

@jetadm123: i know, but i couldn't remove the screw only because there wasn't enough space for the screwdriver.
I think the original problem was the well-known problem with the inverter (capacitors-mosfet-fuses) but i was insecure because i didn't notice any flashlight when turn on the monitor. the display was always black as it was off but the led indicator stayed always green. so, i thought that there might be a problem with the power supply...

@rtech: what is the SMPS? where is located in the board? and how can i test it?

@budm:
1) i cant locate IC1 on picture 3 and i dont know what's P\N (excuse my ignorance )

2) dont know if the method is correct, i obtain these results:

D1: setting the multimeter to 200k, the display returns in one way "out of range", in the other way 136. so i can assume that it's good?

R4: setting to 200k the display returns 136

Q4: assuming the pin named like in the image attached... i cant understand what range of values i must set to measure it (i think i must measure the resistance in all pin combination)


D13: setting to 200k i obtain in way out of range, in the other 93

[jetadm123]

Re: Acer AL2416W Power supply problem

I think budm meant IC2, not IC1. IC2 appears to be a PFC controller with a P/N (Part Number) TDA4863.

Your reading for D1 looks good.

R4 is a 10 ohm resistor. You may have to remove it in order to test it properly.

Measure Q4 the same method you used for the K3568 with pins 1 and 3 on one side and pin 2 by itself on the opposite side.

[lele.v]

Re: Acer AL2416W Power supply problem

yes, on the IC2 it's written "4863G G0718"

i'll try to remove R4 but i'm scared to break it because it's a so little component... :/

for Q4, if 1 is near the writing ic2, 2 the second on the same side and 3 on the opposite side, i obtain the results:

1-2: 1.5
1-3: 19
2-3: 18,5

[retiredcaps]

Re: Acer AL2416W Power supply problem

1-2: 1.5
1-3: 19
2-3: 18,5

1.5 what? 1.5 ohms? 1.5k ohms? 1.5M ohms?

[lele.v]

Re: Acer AL2416W Power supply problem

1.5 what? 1.5 ohms? 1.5k ohms? 1.5M ohms?

yes pardon, 1.5 ohms (multimeter set to 200)

[lele.v]

Re: Acer AL2416W Power supply problem

@jetadm i've tried but i can't remove R4, too little and even if remove the tin the component doesn't move away :/ is really necessary to test it? i've measured again the resistor after i've tried to remove it and now it reads 129 Kohms

@retiredcaps: all the readings for Q4 are intended to be ohms

[budm]

Re: Acer AL2416W Power supply problem

Q4 is shorted, R4 is blown, I can see hole on the body of R4 in post #22 picture, more like the Diode and the IC are damaged also. That means it had short in the Gate to drain of the MOSFET when it blew up, very common. These day when I have blown MOSFET I will always check the components used in the Gate drive circuits and replace the IC. If the IC Gate drive is stuck on, the new MOSFET will be fully on instead of switching at high frequency, this will cause the new MOSFET to blow due to high Source to Darin current because the DC resistance of the transformer is very low, this situation can cause the main fuse to blow and can also damage the bridge rectifier.
When the circuits work properly , the MOSFET will be switcing ON/OFF at about 80,000 times per second, in this mode the Reactive resistance of the transformer winding will be high which is why it does not damage the MOSFET.

[lele.v]

Re: Acer AL2416W Power supply problem

i understand... so what i can do now? you think i can try to repair or it's bettere to throw all away?

[budm]

Re: Acer AL2416W Power supply problem

Well, you will have to try to get the PFC IC, Transistor, may be the Diode. Not sure how good you are at surface mounted repair works.

[ben7]

Re: Acer AL2416W Power supply problem

R4 is 10 ohms
Q4 is a MMBT4403 (a 2N4403 in smd package)
D1 is some type of zener diode, not sure what voltage though.

To remove R4, you have to break the red glue that is under it. you can try a small drill to drill out the center (and the glue) of the broken resistor, then remove the ends of what is left of R4 from the board.

You can also heat both ends of R4 at the same time, and try pushing it to the side, to break the glue. Not recommended though, the pads on the resistor have the possibility to break.

[lele.v]

Re: Acer AL2416W Power supply problem

so, if i want to try to repair i must get:

1xR4 10 ohm smd resistor 1206 (right?)
1xQ4 MMBT4403
1xIC2 TDA4863G
1x K3568
1x T3.15AH250V fuse

that's all or i must check other components?

[lele.v]

Re: Acer AL2416W Power supply problem

dead topic?