Acer AL2416 with bad caps

[Lumberjack777]

Re: Acer AL2416 with bad caps

Hair dryer in one of my best tool, been using it since the 70's, and ESR meter sure help explains what I am seeing. That is my work bench at the non-profit electronics recycle (www.crc.org) place that I do volunteer works fixing electronics every Saturday, I get free pizza, been doing this since 1995, hope to get bigger bench but we do not have that much money. All the stuff I work on (and post on photobucket) are all from this place.

I'll bet they are happy to have you volunteering there. I also volunteer for a nonprofit known as Relectronics. We are basically santa's little helpers right now. Getting all the laptops and monitors ready for the kids on Christmas.

As far as your photobucket database. I have been there many times. It's a warehouse of knowledge. Great job! It's so good to have you, and retiredcaps, jetadm123, Rtech, The_Unique and the others out here to help people.

[budm]

Re: Acer AL2416 with bad caps

Hair dryer in one of my best tool, been using it since the 70's, and ESR meter sure help explains what I am seeing. That is my work bench at the non-profit electronics recycle (www.crc.org) place that I do volunteer works fixing electronics every Saturday, I get free pizza, been doing this since 1995, hope to get bigger bench but we do not have that much money. All the stuff I work on (and post on photobucket) are all from this place.

[Lumberjack777]

Re: Acer AL2416 with bad caps

That's a very interesting diagnostic technique budm. I might start using the hair dryer technique more often. Besides I don't have enough hair to use it on my head anymore. Might as well put it to good use.

You got a little lucky because normally the caps on that inverter board take out one of the transistors (P2804BDG or P5504EDG) and at least one of the white smd fuses marked with an "M". I circled them in red for anybody who reads this thread in the future.

And the last picture with the working monitor made me very happy. Because your workshop looks just like mine. With everything exactly in its right place.

[jetadm123]

Re: Acer AL2416 with bad caps

The way they mounted those caps, you can't help but think that the board was originally designed for SMD caps. Instead, it looks like they cheaped out and installed lower quality caps.

[retiredcaps]

Re: Acer AL2416 with bad caps

Ahh, yes those EVL caps on the inverter board are always prime suspects.

[budm]

Symptom: The backlights will flash on for seconds.
The bad caps (bulging tops) in the power supply were replaced as a set.
The 24V, 5V and all the signals are present after new caps are replaced.
The 24v and the BL_ON are shown up at the inverter board but it still just does the 2-seconds to black. Used a set of test lamps and it still blacks out.
So I heated up the 10 caps (100uF 35V) on the inverter board with hair dryer, the backlights then stay on.
Removed all 10 caps and check the capacitance, all are within 20%, check ESR with my home made ESR meter, 4 of them has >10 Ohms. I heated them up with hair dryer, then the ESR dropped down to 0.1 Ohm.