Acer AL-2416w dead.

[jetadm123]

Re: Acer AL-2416w dead.

Ive just checked the 14 pin connector & checks out as it should, ive re-checked the fuses with DMM set at 200ohms (as mentioned on other post) & F1 is showing zero, I couldnt find the value of the fuse on the other thread so i really could do with some suggestions on what it could be as well as what to check next.,,,,cheers.

When you say F1 is showing zero, do you mean zero ohms? If yes, then that means the fuse is good. Or, does your meter shows zero when open circuit? Please clarify. Also, please post a photo of your entire inverter board. Tough to jump between different threads when trying to analyze a problem.

[froggy]

Re: Acer AL-2416w dead.

I checked the fuse with no power to the board, youve really confused me regarding the meter as i thought they would all read the same way,
As stated im only a beginner so what might be 2nd nature to you is something new to me,
Anyhow here is a picture of the inverter although its awkward to get a close up due to the boards width. In the meantime how do i go about testing Q3 to Q6 & do i test them in situ?.....thanks.

[retiredcaps]

Re: Acer AL-2416w dead.

See post #13

https://www.badcaps.net/forum/showthread.php?t=10419

In post #13, there is a section that talks about multimeters and how to interpret the readings.

There is also a section on how to test transistors for shorts.

[froggy]

Re: Acer AL-2416w dead.

Thanks for putting me onto the guide that saved alot of questions, ive just checked Q3 to Q6 & im getting obsolutely no reading on all but one!, Also checked fuses F1 to F3 & got the following:
F1---0.00
F2---0.8
F3---0.8
Looks like im in the market from some fets & two fuses, But i must ask what has caused these fets to go pop?, Its just that id hate to change them all if there is an underlying problem thatll do the same again, Is it advisable to change the caps for safetys sake?, (sorry, more questions but at least im learning!).

[retiredcaps]

Re: Acer AL-2416w dead.

ive just checked Q3 to Q6 & im getting obsolutely no reading on all but one!

1) Let's slow down a bit here.

2) Please post a picture of your multimeter.

3) Put your multimeter on 200 ohms. Touch your black and red probe together. What is the reading?

4) A multimeter ALWAYS gives a reading. It is a matter of interpretation.

[froggy]

Re: Acer AL-2416w dead.

Here is a picture of my DMM with reading taken @200ohm & both probes touching, dont tell me im doing something daft!.

[retiredcaps]

Re: Acer AL-2416w dead.

Okay, when the probes are touching you are getting 0.9 ohms. This is the lowest reading, in theory, you should get when reading a "good" fuse.

The readings for F2 and F3 (0.8 ohms) are more likely what you should get for a good fuse.

If you are reading 0.00 ohms in F1, it means you may be doing something wrong. I suggest re-measuring F1.

To measure Q3-Q6, list all the readings doing the following procedure.

Set the multimeter to 200 ohms (two hundred). You can test for shorted transistors "in circuit" (with power off and unplugged)

a) put black probe on pin 1 and red probe on pin 2 - read/record ohm
b) put black probe on pin 1 and red probe on pin 3 - read/record ohm
c) put black probe on pin 2 and red probe on pin 3 - read/record ohm

You should have 3 readings for Q3, 3 for Q4, 3 for Q5, and 3 for Q6. So you should have 12 readings in total. List them all.

"1" of the left hand side of the multimeter means the resistance is greater than 200 ohms and is a "valid" reading.

All the above will take less time to do than it took for me to write it out.

[froggy]

Re: Acer AL-2416w dead.

O.k here are my results:

Q3/ 1&2-----1
1&3-----1
2&3-----1*

Q4/----same as above

Q5/ 1&2-----3.5
1&3----1.7
2&3----2.7

Q6/ The same as Q3 & Q4

The (*) denotes meter flashing random numbers before settling on "1" as opposed to not moving & staying on "1".

FUSES.
F1-------1
F2------0.9
F3------0.8.

I hope you can make something of these figures.

[retiredcaps]

Re: Acer AL-2416w dead.

Q5/ 1&2-----3.5
1&3----1.7
2&3----2.7

Q5 is shorted and probably bad. Desolder and perform the exact same test on the transistor when it is out of circuit. If the readings are similar, then Q5 is 100% bad.

FUSES.
F1-------1
F2------0.9
F3------0.8.

F1 is open and bad. Replace F1. Note if F1 was 1.0 on the right hand side, it would be a good fuse. But since you are seeing "1" on the left hand side, F1 is bad.

[froggy]

Re: Acer AL-2416w dead.

Great stuff!, i`ll get onto it sometime tomorrow as the mrs has just come in & doesnt appreciate the dining table doubling up as a workbench!, Plus the fact i dont have any fuses so will have to order them in, would a 2 amp be o,k?, I noticed on another thread somebody had used a 1.25 amp but i cant find any on ebay.

[Lumberjack777]

Re: Acer AL-2416w dead.

Bonney from the UK, on the other thread, posted a supplier for the transistors and those mini-caps (if you want them) http://www.chsinteractive.co.uk/elec...r-ass-make.htm

As far as the fuse(s) go. Depends on the color and marking of it. If it's white with an "M" then it was tested on the other thread to work with a 1.25A fast blow. Those generally are not too tough to find if you look around.

Two important details to remember if you want this to last. The first is why the transistor and fuse shorted in the first place. Personally, I would replace those 100uF 35 V mini-caps. They are cheap on that website I posted. The second is to desolder the transistor carefully. You don't want to lift a copper trace. There were 2 methods of desoldering explained in the other thread. These are surface mount components and it does take some skill to desolder, and solder them properly. You might want to practice on a spare board if you have not done much soldering before. I invested in a "chipquik" kit to help with the SMD desoldering.
Hope that helps.

L-J-7

[retiredcaps]

Re: Acer AL-2416w dead.

Personally, I would replace those 100uF 35 V mini-caps.

I agree.

[froggy]

Re: Acer AL-2416w dead.

Thanks everybody for the info, I was going to ask about the transistor removal but you beat me to it,i can see legs 1&3 solder points but where is no2?, is that the large bit across the top?, I will get a bunch of the mini caps in & get them done,The fuse as far as i can see has no markings on it but is white in colour, ive just been sifting through my late fathers soldering iron collection & they all seem to be a bit large for delicate work, my fathers hobby was repairing crt tv`s where the components were larger & less hassle so it looks like another soldering iron to add to the shopping list (suggestions?), anyhow i`ll follow up on bonneys link later today & get the components ordered,,,,,,,many thanks.

[froggy]

Re: Acer AL-2416w dead.

Regarding the caps on this inverter, I found this on an auction site & wondered what is going on with the caps & is it a consideration as a mod?. (sorry about pic quality but had to shoot direct from screen).

[PlainBill]

Re: Acer AL-2416w dead.

That looks like someone was unable to find caps that would fit and shoehorned physically larger caps into the space. This doesn't inspire confidence in the seller.

PlainBill

[froggy]

Re: Acer AL-2416w dead.

That looks like someone was unable to find caps that would fit and shoehorned physically larger caps into the space. This doesn't inspire confidence in the seller.

PlainBill

That was my first thought Bill, but the thing is there are 4 caps in place of the standard 8, I was only wondering if its an easier but safe option.

[jetadm123]

Re: Acer AL-2416w dead.

The original cluster of 4 caps are probably in parallel, which gives you a total capacitance of 400uf. If you look closely at the photo, two 220uf were used to give a total of 440uf.

[Lumberjack777]

Re: Acer AL-2416w dead.

i can see legs 1&3 solder points but where is no2?, is that the large bit across the top?

Yes, the back is the 2nd leg. It's soldered on top AND on the back. It took me a lot of heat to get the solder on the back to melt completely. There's 2 methods explained to remove those on the other thread. Another guy recommended a heat gun. (which I didn't have)

That looks like someone was unable to find caps that would fit and shoehorned physically larger caps into the space. This doesn't inspire confidence in the seller.

PlainBill

I agree Bill. Now he's going to sell it? That "repair" looks like it will last maybe 2 weeks.

That was my first thought Bill, but the thing is there are 4 caps in place of the standard 8, I was only wondering if its an easier but safe option.

The caps come off fairly easily. Just suck up the solder with some desoldering braid. Then put the tip of the soldering iron down on the cap wire leads; and wait for the solder to melt. Then gently bend each lead up or away from the copper trace with the tip of the soldering iron.

The original cluster of 4 caps are probably in parallel, which gives you a total capacitance of 400uf. If you look closely at the photo, two 220uf were used to give a total of 440uf.

Very good eye there. We'll have to nickname you hawkeye. Putting the capacitance on 2 caps instead of 4 is really dumb. I doubt that "repair" will last 2 weeks.

Hey froggy. If you have any questions just come back and ask. I have seen this repair done at least 10 times, and it always worked. No worries mate.

L-J-7

[froggy]

Re: Acer AL-2416w dead.

Well so far ive replaced all 10 caps with no bother, the Q5 fet was a bit of a pig to get off though, i took the advice & practiced on an old board which nicely filled up the swear jar in the process!, I found my late fathers 80w iron with approximately a 1/2 inch tip(he used it on LOT`s) desoldered the back of the fet from the board nicely but used my baby one for pins 1 & 3, Is there any reason why the fet has so much solder on the back of it?, i really didnt want to solder the new one on with the huge iron so i soldered the fet across the top only, All i need to do now is the F1 fuse but dont know what size to order (length & width), any suggestions welcome,,,,,,cheers!.

[PlainBill]

Re: Acer AL-2416w dead.

Well so far ive replaced all 10 caps with no bother, the Q5 fet was a bit of a pig to get off though, i took the advice & practiced on an old board which nicely filled up the swear jar in the process!, I found my late fathers 80w iron with approximately a 1/2 inch tip(he used it on LOT`s) desoldered the back of the fet from the board nicely but used my baby one for pins 1 & 3, Is there any reason why the fet has so much solder on the back of it?, i really didnt want to solder the new one on with the huge iron so i soldered the fet across the top only, All i need to do now is the F1 fuse but dont know what size to order (length & width), any suggestions welcome,,,,,,cheers!.

The solder is for heat transfer - the copper on the PC board helps dissipate heat.

I've found the best way to determine the dimensions of a fuse is to measure it.

PlainBill