Acer AL2216W Repair Question

[selldoor]

Re: Acer AL2216W Repair Question

You should observe the polarity when doing this Red probe to positive leg black lead to negative. In your photo looks like negative is on the right.


Just to check - when you did the 5v test you did have the boards connected?

Also in the pictures the boards are on a metal frame? If they are fixed in their normal position that is ok but do not turn on if they are resting on anything conductive.

[trains58554]

Re: Acer AL2216W Repair Question

@jetadm123,

On the big cap. I got 168.9VDC. Earlier when I was checking the 5 volts the surge protector was not plugged in so I rechecked that and still no 5 volts.

@selldoor,

Yep the negative terminal was on the right. yep both boards where hooked together and screwed into there normal place.

[retiredcaps]

Re: Acer AL2216W Repair Question

On the big cap. I got 168.9VDC.

Delta board. Jetadm123 knows this board very well.

I circled the startup cap. It is probably 22uF 50V.

1) What is the DC voltage across this capacitor?
2) Is it steady or fluctuating?
3) On the backside of the board, there is a 8 pin IC (probably U102) that is the SMPS. What is the part number?

[jetadm123]

Re: Acer AL2216W Repair Question

After you perform retiredcaps suggested measurements, two things have come to mind:

1) You are not getting 5VDC, but are you getting 12VDC?

2) Most of this series of Delta boards have a fused 5V output. IIRC, the fuse is something like F101 or F102 and it's a surface mount component on the bottom of the board with a "M" or "W" (depending on how you look at it) stamped on it. Check to see if it's open. Also, a good focused photo of the bottom of your power board would be helpful. There may be other surface mount fuses and it wouldn't hurt to check them as well.

[trains58554]

Re: Acer AL2216W Repair Question

@retiredcaps,

The voltage was steady at 38 volts.

as for the 8 pin ic on the back. u101 LM393 I believe that one is hard to read. U105 is EA1532A

@jetadm123,

nope no 12 volts.

I checked the fuse with the w on it and the others that look the same and they where all still good.

[retiredcaps]

Re: Acer AL2216W Repair Question

@retiredcaps,

The voltage was steady at 38 volts.

U105 is EA1532A

1) Hmm, 38V DC is higher than I expected.

2) Refer to

http://pdf1.alldatasheet.com/datashe.../TEA1532T.html

See figure 3 on page 4 for the pinout.

3) Put your black probe on pin 2 (GND). Put your red probe on pin 1 (VCC). Be careful not to let the probes touch and short out your IC. What is the DC voltage reading? Is it steady?

[trains58554]

Re: Acer AL2216W Repair Question

ok I was getting 34.46 volts steady.

[retiredcaps]

Re: Acer AL2216W Repair Question

ok I was getting 34.46 volts steady.

Still high. What is the VCC to GND on the U105?

[trains58554]

Re: Acer AL2216W Repair Question

It is the 34.46 volts from above is the U105 ic

[retiredcaps]

Re: Acer AL2216W Repair Question

ok I was getting 34.46 volts steady.

For the small cap, are you putting your red probe on the positive leg and black probe on the negative leg and measuring DC voltage?

The TEA1532 VCC maximum voltage rating is 20V DC. If 34.46V is being fed into the IC, the IC might be fried.

[trains58554]

Re: Acer AL2216W Repair Question

I checked the U105 wrong I am getting 9.8 volts. I was checking from pin 1 to the ground tab but this time I put the red lead on pin 1 and the black lead on pin 2 ground

[retiredcaps]

Re: Acer AL2216W Repair Question

I checked the U105 wrong I am getting 9.8 volts. I was checking from pin 1 to the ground tab but this time I put the red lead on pin 1 and the black lead on pin 2 ground

9.8V DC is too low for the SMPS to start. It requires typically 11V DC.

Can you remeasure the startup cap as per my instructions in post 30?

[trains58554]

Re: Acer AL2216W Repair Question

I checked it again. It started at 5 volts and was down to 4.9 after 5 seconds. With full power being suppled.

[retiredcaps]

Re: Acer AL2216W Repair Question

What is part number Q102?

[trains58554]

Re: Acer AL2216W Repair Question

I did not see the Q102 on the board but I think I found the problem the 22uf 50volt cap is not making a very good connection.

[retiredcaps]

Re: Acer AL2216W Repair Question

Q102 is just above the small cap. There is also F100 (a fuse). A bad solder joint would cause problems.

[trains58554]

Re: Acer AL2216W Repair Question

Ok we are getting somewhere now. I have the small cap soldered in again. Now When I turn the power on to the monitor the light flashes orange for a millisecond then off. I still did not see the q102 or the f100 if we still need those values I will look again.

[trains58554]

Re: Acer AL2216W Repair Question

I also just checked the SMPS again and I am still getting 9.8 volts

[retiredcaps]

Re: Acer AL2216W Repair Question

Ok we are getting somewhere now. I have the small cap soldered in again. Now When I turn the power on to the monitor the light flashes orange for a millisecond then off. I still did not see the q102 or the f100 if we still need those values I will look again.

See diagram. Green is Q102. Blue is F100.

What is the DC voltage reading across the small capacitor after resoldering?

[jetadm123]

Re: Acer AL2216W Repair Question

If you look at your first photo of the power board, look to the left of the startup cap. Q102 is the transistor mounted on the heatsink. If you look a little higher, you'll see F100.

What exactly was wrong with the startup cap?

Oops! Retiredcaps beat me to it!