No power on a Acer AL1916

[selldoor]

Re: No power on a Acer AL1916

Nice fix! perhaps clean up joints on the voltage regulator top of pic 2.

Visited Tallinn earlier this year - very interesting place for a few days break
and had a day out to helsinki probably on a monday as I recall a lot of Tallinn
is closed.

[kose2ik]

Re: No power on a Acer AL1916

Hi, i have the same problem,
my monitor restarting on hot days, until one day has no power.
I am was confused.
I thought that soldering is a crack somewhere and
I began to suspect ran over the solder and suspected U406 too .
Now, I was confirmed, and the removal of this U406 and works.
Now need to add a monitor in extra fan.

Thanks

[freaker]

Re: No power on a Acer AL1916

Thanks PlainBill and others for this thread. I have a View Sonic VG720 and pulled it off a shelf today. Been there a few years and maybe before this thread. Had discovered the SOT-23 burnt and was able to scrape at it and expose the bare material below. No schematics at the time and no money, so just shelved it.

Now while going after schematics and replacement parts, google turned up this thread. I tried the second fix on page 2 and eureka it works.

BTW found some schematics both of which have the U406 ASM810MEURF-T
715g1558-2-2
https://cdn.badcaps-static.com/pdfs/...308b16c8cb.pdf
715g1558-3-2


Thanks again.

[QuantumCheese]

Re: No power on a Acer AL1916

Once again this site come up trumps

I have a pair of these and a couple of days ago, the right-hand one started power-cycling itself. which was an inconvenience to say the least as i had a schematic spread across both and half of it kept vanishing!

Anyway, the caps looks ok, it took a few out & measured them, again OK. I thought the 12V had quite a lot of switcher noise on it ~0.1V p-p so I’ll bet a cap is going to go soon.
Apart from that I couldn't really find anything obviously wrong and the power-cycling was seemingly random, it could go 30 mins fine and then it could go every couple of secs for a bit and then again work for another 30 mins.

Then i came across this thread. Unlike the comedic method described a littler higher up , i used the traditional method of de-soldering the little blighter (u406) and it's now working fine

I've got no plans to put it back as the circuit has an RC to 3v3 anyway. i think that little POR device was overkill and it can easily live without it.

Cheers again all

[jetadm123]

Re: No power on a Acer AL1916

If your power board uses zener diode ZD903, try checking it for shorts. It's across the 5V and 12V outputs.

[retiredcaps]

Re: No power on a Acer AL1916

.
Big Cap: 325V (that's OK, since I've got 220V AC)
after a few minutes connected to AC, gave ~350V

black - 0.00v
brown - 0.00v
red - between 13v and 13.20v, oscillates randomly, after a few minutes gave a bit higher reading, still in an oscillating fashion)
orange 0.00
green ~ 5v (oscillates, +- peaks a bit wider than red)
Yellow ~ 5v (oscillates, +- peaks a bit wider than red)
blue 0.00v
black 0.00v

Also, one more thing: the PSU emits a low volume click-like sound every 4 or 5 seconds (sounds like a relay or something, but I'm not really an expert in this field)

1) Upload your pictures so they are hosted on this forum following the instructions in my sig file EXACTLY. I will NOT look at any pictures that are hosted offsite for a number of reasons including unwanted pop-ups, malware, etc.

2) Your SMPS is not starting up properly which is causing the the DC voltage fluctuation.

3) Reasons could be (which will require a multimeter to test)

a) bad SMPS IC
b) bad startup cap
c) shorted component like a diode on the secondary side

[ogisha007]

Re: No power on a Acer AL1916

First of all, my congratulations on a forum this large and full of expertise.

Now, to present my problem.

I got this monitor from a friend, he did a caveman U406 fix, shorted the bottom contacts with wire, but didn't solder, instead he used duct tape to fix it in place(?!?!?)...

Needless to say, that stopped working after a while, he once more tried to bridge the contacts, with wax no less (?!?!?!), but then the monitor finally decided to die. So it's up to me to revive it (if possible), in order to use it in my soon-to-be MAME cabinet.

What I've done so far:

Soldered bottom U406 contacts, but still won't turn on. My suspect is the PSU, since it gives out there voltages:

Big Cap: 325V (that's OK, since I've got 220V AC)
after a few minutes connected to AC, gave ~350V

black - 0.00v
brown - 0.00v
red - between 13v and 13.20v, oscillates randomly, after a few minutes gave a bit higher reading, still in an oscillating fashion)
orange 0.00
green ~ 5v (oscillates, +- peaks a bit wider than red)
Yellow ~ 5v (oscillates, +- peaks a bit wider than red)
blue 0.00v
black 0.00v

Also, one more thing: the PSU emits a low volume click-like sound every 4 or 5 seconds (sounds like a relay or something, but I'm not really an expert in this field)

The caps look more or less OK, i really hope it's not a total goner.

Some bad pics (3.2MP camera and 1 AM, what can i do?)



If you need any more pics/measurements, feel free to hassle me, I got plenty of free time and solder.

[apopleptic]

Re: No power on a Acer AL1916

***Update***
I decided to just gently remove u406 and afterwards was able to get the monitor to turn on and work just fine. So for now the monitor is working.
***Update***

Amazing. I take it you haven't read the thread. The fault and the solution is discussed on the second page of this thread. No parts or purchases required.

PlainBill

Are you are talking about u406? shorting the two pins did not allow the LED to turn on, and I still get no results from the power button.

Actually I did read the whole thread. Twice. But as I mentioned in my first post to this forum yesterday I am new to this troubleshooting of electronic boards, so I posted in an attempt to get help understanding what, if anything I'm doing wrong in this testing. I appreciate your comment yesterday about testing the voltage between both polls of the capacitor, it was the first time I ever tested a cap. Prior to that I was testing from voltage to a common ground screw.
Maybe I'm taking this prsonally, but the tone of the people on this board has been a little bit... unwelcoming... Anyhow, thanks for the useful info. I'll ask my friend to help me with this. Maybe if I point him to this forum he'll get a more friendly response than I did.
Thanks...

[PlainBill]

Re: No power on a Acer AL1916

Technian error indeed. from post to post i get 160V dc. Thanks. I guess I continue with the testing.


I was posting from my mobile phone which wouldn't let me attach the pictures.

Amazing. I take it you haven't read the thread. The fault and the solution is discussed on the second page of this thread. No parts or purchases required.

PlainBill

[klkmalik]

Re: No power on a Acer AL1916

I had same problem this model but I changed vga logic board it was working fine.

[apopleptic]

Re: No power on a Acer AL1916

It could be either, or it could be 'technician error'. Depending on the line voltage it should be at least 100 volts higher. Are you measuring across the two leads of the cap?

The first post in this thread has a picture of the power supply. Is your supply identical? If not, we will need a picture of your supply.

PlainBill

Technian error indeed. from post to post i get 160V dc. Thanks. I guess I continue with the testing.

See post #61.

I was posting from my mobile phone which wouldn't let me attach the pictures.

[PlainBill]

Re: No power on a Acer AL1916

I have this same monitor. When I take a reading from the large capacitor it comes back a 65 volts dc.
does that mean a capacitor is bad or something before the cap?
I am new to soldering and may request someone to assist me with soldering later so I would like to know exactly what I need to have done.
thanks for all the help.

It could be either, or it could be 'technician error'. Depending on the line voltage it should be at least 100 volts higher. Are you measuring across the two leads of the cap?

The first post in this thread has a picture of the power supply. Is your supply identical? If not, we will need a picture of your supply.

PlainBill

[retiredcaps]

Re: No power on a Acer AL1916

I have this same monitor.

See post #61.

[apopleptic]

Re: No power on a Acer AL1916

I have this same monitor. When I take a reading from the large capacitor it comes back a 65 volts dc.
does that mean a capacitor is bad or something before the cap?
I am new to soldering and may request someone to assist me with soldering later so I would like to know exactly what I need to have done.
thanks for all the help.

[Cory_Jackson]

No power on a Viewsonic VG920

Sharing my experiance and thanks. Had a dead VS VG920, no power up, no LED. Found this forum via Google and followed this thread. Tested U406 by shorting bottom pins and pressing power button several times and got some action. I then popped off U406 lower right as facing it and the monitor works perfectly. I reckon if it acts up more I'll replace the transistor then. But it seems that it functions acceptably without it. Thanks everyone! I will be bookmarking this site!

[jsog]

Re: No power on a Acer AL1916

A missing reset controller should not do that, but bad capacitors might. Remember that they can look good without being good.

[AleHop]

Re: No power on a Acer AL1916

Very short time before I found a problem that hadn't happened before.

I didn't realise yesterday as it was a quick test just to see if it turned on basically. The problem are some vertical stripes and I don't know if it has anything to do with not replacing the reset circuit E406 MAX810.

What do you think?



The stripes are not as clear and annoying on that picture as it is in reality. The screen look a bit foggy, mainly on the borders, but it won't show on a picture. It might be that I have damaged something while removing the E406 or something else.

I'll try to replace the Maxim reset circuit ASAP and see if that makes a difference. I'm afraid it won't solve the problem so any advice is welcome.

[AleHop]

Re: No power on a Acer AL1916

There is a big mystery about this particular GPU. I'm coming to the conclusion that the reset controller should never have been installed, but I can't find any documentation to prove that.

No, the reset circuit should not have anything to do with refresh rate.

PlainBill

Ok, I'll leave the MAX810T and will use the LCD monitor without it. If I find any problem or I see an unexpected behaviour I let you know.

Than you very much again PlainBill.

[PlainBill]

Re: No power on a Acer AL1916

Same problem here with the Acer AL1916. I removed the U406 Maxim reset circuit and it works no problem. I checked all the capacitors and visually they all seem brand new.

I want to replace that circuit but I can only find the reference MAX810MEUR+T from RS Amidata but I don't know if that's what I want.

I used a 26 Watts solder, I wonder if it's ok. Two more questions.

1.- Many people around the world seem to have just the same problem with that LCD. Can I be certain about most probably having the same problem in the future?

2.- Could that reset circuit has anything to do with refresh rate on the LCD.

Thank very much everybody at badcaps.net and special thanks to PlainBill.

There is a big mystery about this particular GPU. I'm coming to the conclusion that the reset controller should never have been installed, but I can't find any documentation to prove that.

No, the reset circuit should not have anything to do with refresh rate.

PlainBill

[AleHop]

Re: No power on a Acer AL1916

Same problem here with the Acer AL1916. I removed the U406 Maxim reset circuit and it works no problem. I checked all the capacitors and visually they all seem brand new.

I want to replace that circuit but I can only find the reference MAX810MEUR+T from RS Amidata but I don't know if that's what I want.

I used a 26 Watts solder, I wonder if it's ok. Two more questions.

1.- Many people around the world seem to have just the same problem with that LCD. Can I be certain about most probably having the same problem in the future?

2.- Could that reset circuit has anything to do with refresh rate on the LCD.

Thank very much everybody at badcaps.net and special thanks to PlainBill.