No power on a Acer AL1916

[RobertoIsRad]

Re: No power on a Acer AL1916

Finally, results! I tested using the second method and immediately after shorting the pins with a screw driver the led turned on, the screen didn't but at least it's a start. This happened with both monitors!
It might be a small part but I think I may be able to solder a new one in if you believe this to be the defect. I searched for MAX810M on digikey but there were more characters after the "m". I was going to order this part number MAX810MTRGOSCT-ND. Is That correct? Thank you so much

[PlainBill]

Re: No power on a Acer AL1916

Finally, results! I tested using the second method and immediately after shorting the pins with a screw driver the led turned on, the screen didn't but at least it's a start. This happened with both monitors!
It might be a small part but I think I may be able to solder a new one in if you believe this to be the defect. I searched for MAX810M on digikey but there were more characters after the "m". I was going to order this part number MAX810MTRGOSCT-ND. Is That correct? Thank you so much

Bear with me for a minute, please. I had one thought last night about this problem. Have you tried replacing any caps in the power supply? If the caps in the 5 Volt supply have not been replaced ther is a small chance that the ultimate cause of the problem is excessive ripple resetting the reset controller. I don't think that is the problem, but want you to be aware of the possibility (I'd rate the chances as less than 10%).

As far as the proper number, I don't know, and haven't been able to find out. The MAX810M is the right polarity and output for this application. The other variable is package. The MAX810M is available in two packages, the SOT23-3 and the SC70-3. It's important to get the right one because the lead spacing is different on the two packages. SOT23-3 is 3 mm long, sc70-3 is 2 mm long.

PlainBill

[RobertoIsRad]

Re: No power on a Acer AL1916

Okay, I measured the part and it is 3mm so I will order the $0.58 one (SOT23-3). Could you tell me which caps are for the 5v so maybe I can order caps and diodes but replace the caps first to make sure?

On second look they're 2mm apart, maybe I'll just order both and save shipping...

[PlainBill]

Re: No power on a Acer AL1916

Okay, I measured the part and it is 3mm so I will order the $0.58 one (SOT23-3). Could you tell me which caps are for the 5v so maybe I can order caps and diodes but replace the caps first to make sure?

On second look they're 2mm apart, maybe I'll just order both and save shipping...

Wow!! I never noticed that before. Look at the picture of the caps. It looks like those two may be bulging at the top.

I'm not good at recognizing cap brands unless I read the label. And these are positioned so the brand's not readable. What brand are they? If they are on the 'crap brand' list they should be replaced.

Anyway, here is a list of the caps by location.

5V supply
1000 uF @ 16V C924
470 uF @ 16V C926

12V supply
1000 uF @ 25V C923, C931 (yes, two of them)
470 uF @ 25V C925

SMPS supply
100 uF @ 25V C906
47 uF @ 25V C909

Inverter
470 uF @ 25V C203

PlainBill

[RobertoIsRad]

Re: No power on a Acer AL1916

Ok great. I'll probably order these either today or tomorrow. Then it will take a few days to get them. I'll let you know how it goes. Thanks again!

[PlainBill]

Re: No power on a Acer AL1916

Ok great. I'll probably order these either today or tomorrow. Then it will take a few days to get them. I'll let you know how it goes. Thanks again!

Well, at least you're close to Digikey. At one time I lived at the opposite end of the Twin Cities (Mound). Can't say that I miss the snow. High today is only up to the mid 70's.

PlainBill

[RobertoIsRad]

Re: No power on a Acer AL1916

Thank you so much Bill!!! I'm sorry it took so long for an update... The first monitor I replaced all the caps and there was no change. So Then I put in the new controller and it turned on beautifully! Then I replaced the controller in the other one (I'll replace the caps later) and same thing, Works Perfect! So I thank you once again, I couldn't have done it without you! I now have two perfectly fine monitors

[PlainBill]

Re: No power on a Acer AL1916

Thank you so much Bill!!! I'm sorry it took so long for an update... The first monitor I replaced all the caps and there was no change. So Then I put in the new controller and it turned on beautifully! Then I replaced the controller in the other one (I'll replace the caps later) and same thing, Works Perfect! So I thank you once again, I couldn't have done it without you! I now have two perfectly fine monitors

Glad to hear it!!!

PlainBill

[Xeoncross]

Re: No power on a Acer AL1916

Just disassembled my "Acer AL1916A B" like above and I belive that I have the same problem with the power supply board. I'm a real DIY guy when it comes to PC's so I'm interested in following the advice here and replacing the caps.

The only problem is that I have never soldered anything.

Anyway, the only caps that seem to be bulging are the C0612 (1000 uF @ 25V) and the C0604 (1000 uF @ 16V) as shown below. The video board looks good. I'm hoping that I can just remove them an then solder replacement caps into their place. The depth of my knowledge is http://www.youtube.com/watch?v=on_2CP52cW4 so let me know if I'm about to shoot myself in the foot and need to go learn more first.

[Xeoncross]

Re: No power on a Acer AL1916

Oh, I forgot to mention that I also need to know what exactly to buy. I was checking out the shopping guide and then I realized that I didn't know what type of caps these were. I also included another shot of the other capacitors on the board just in case.

[PlainBill]

Re: No power on a Acer AL1916

Oh, I forgot to mention that I also need to know what exactly to buy. I was checking out the shopping guide and then I realized that I didn't know what type of caps these were. I also included another shot of the other capacitors on the board just in case.

Two threads in the FAQ subforum will help you, 'Which Caps Should I buy?', and 'Where can I buy caps?'. Note that the list of series in these threads is reversed from real life - the best caps are on the right.

A recommended approach is to make a list showing the value, voltage, diameter, and height of the caps being replaced. (A shortcut is to only measure the diameter of caps close to one another, and note the maximum permissible height for the caps.)

This post shows how to select the appropriate caps at Digikey. A similar technique will work at Mouser.

If you wish, post the list and the replacement you chose if you wish to have your choices verified.

PlainBill

[jmb2112]

Re: No power on a Acer AL1916

I recently was given an AL1916 monitor with the same problem-no power, no led light. I confirmed it was the same problem with U406 on the main board (I shorted bottom two pins and hit power button - got lit up screen with acer logo). Was going to order part but further googling (foreign language forums) revealed that U406 (Max810g part) could just be removed and monitor would work. I used a needle nose plier and just pulled it off the board (I guess you could just break it up, also). When plugged in, the monitor immediately powered up without hitting the power button, but will turn off and on using power button. I've only used it for a day, but it worked fine. A much easier fix than trying to solder a surface mount component the size of the tip of a pencil with three leads. Any comments appreciated on this method of repair.

Thanks for your posts! Jim

[PlainBill]

Re: No power on a Acer AL1916

I recently was given an AL1916 monitor with the same problem-no power, no led light. I confirmed it was the same problem with U406 on the main board (I shorted bottom two pins and hit power button - got lit up screen with acer logo). Was going to order part but further googling (foreign language forums) revealed that U406 (Max810g part) could just be removed and monitor would work. I used a needle nose plier and just pulled it off the board (I guess you could just break it up, also). When plugged in, the monitor immediately powered up without hitting the power button, but will turn off and on using power button. I've only used it for a day, but it worked fine. A much easier fix than trying to solder a surface mount component the size of the tip of a pencil with three leads. Any comments appreciated on this method of repair.

Thanks for your posts! Jim

Why not go caveman and just smash it with a rock? Modern man has invented this tool called a Soldering Iron that we find useful for removing components.

I'm thinking the look on your face would have been priceless if the monitor had NOT started right up.

PlainBill

[Xeoncross]

Re: No power on a Acer AL1916

Ok, I want to replace the C0612 (1000 uF @ 25V) and the C0604 (1000 uF @ 16V).

After reading all the forum FAQ's and tutorials I'm still having trouble figuring out what types of caps I need. Maybe someone can let me know if this is right.

C0612 (1000 uF @ 25V)
http://search.digikey.com/scripts/Dk...&name=P5544-ND

C0604 (1000 uF @ 16V)
http://search.digikey.com/scripts/Dk...&name=P5533-ND

Again, here is a shot of them. (Front left and back right)

[PlainBill]

Re: No power on a Acer AL1916

Ok, I want to replace the C0612 (1000 uF @ 25V) and the C0604 (1000 uF @ 16V).

After reading all the forum FAQ's and tutorials I'm still having trouble figuring out what types of caps I need. Maybe someone can let me know if this is right.

C0612 (1000 uF @ 25V)
http://search.digikey.com/scripts/Dk...&name=P5544-ND

C0604 (1000 uF @ 16V)
http://search.digikey.com/scripts/Dk...&name=P5533-ND

Again, here is a shot of them. (Front left and back right)

No.

Read the FAQ on 'Which caps should I use?'.
Read the FAQ on inserting pictures.
Read the thread I linked to on selecting caps.
As a minor point, I don't see signs of bulging, but you ARE closer to the caps than I am.

PlainBill

[Wrog]

Re: No power on a Acer AL1916

Ok, I want to replace the C0612 (1000 uF @ 25V) and the C0604 (1000 uF @ 16V).

After reading all the forum FAQ's and tutorials I'm still having trouble figuring out what types of caps I need. Maybe someone can let me know if this is right.

A recommended approach is to make a list showing the value, voltage, diameter, and height of the caps being replaced. (A shortcut is to only measure the diameter of caps close to one another, and note the maximum permissible height for the caps.)

As PB says, make a list of the caps you want to replace, and someone will make suggestions on which to buy. Reason being, there are MANY MANY different caps out there (as you've seen by searching) and you need to make sure the replacements will both work AND fit!

[sceva]

Re: No power on a Acer AL1916

Why not go caveman and just smash it with a rock?

I laughed out loud at this comment. PlainBill can be quite the character....

I found this thread while researching a problem with a ViewSonic VG920, which must have the same or very similar logic board. Following Bill's advice, I found the component at U406 to be faulty. I promptly ordered a replacement from digi-key. Then I finished reading the thread and saw the comment about removing the component and it works. I wanted to test and make sure there wasn't other problems on the inverter side, so I removed the component (with a soldering iron, not a rock - I couldn't find a rock the proper size...), powered it up, and it works perfectly.

So, is there a danger in not having the component installed? What does this part do?

Thanks for the info and the laugh!

[PlainBill]

Re: No power on a Acer AL1916

I laughed out loud at this comment. PlainBill can be quite the character....

I found this thread while researching a problem with a ViewSonic VG920, which must have the same or very similar logic board. Following Bill's advice, I found the component at U406 to be faulty. I promptly ordered a replacement from digi-key. Then I finished reading the thread and saw the comment about removing the component and it works. I wanted to test and make sure there wasn't other problems on the inverter side, so I removed the component (with a soldering iron, not a rock - I couldn't find a rock the proper size...), powered it up, and it works perfectly.

So, is there a danger in not having the component installed? What does this part do?

Thanks for the info and the laugh!

I always recommend looking up the datasheets when you have a question like that. Unfortunately, a detailed datasheet is not available for the processor, so I can't get an idea of how important the reset controller really is.

Background: Many processors generate voltages internally. Way back in antiquity the 8080 required three power supplies (+12, +5, -5 volts). Later processors generated these voltages internally via charge pumps. Since the processor could not begin operation until the internal supplies were stable, some means of holding the processor in reset was required. In the IBM PC, XT, AT, and later compatible systems this was accomplished by the power supply. The reset line would stay active until several milliseconds after all power supply outputs were stable.

The reset controller Does something similar. It monitors it's input voltage, and holds the reset line active (either high or low, depending on dash number) until a certain number of milliseconds after the input voltage rises above the threshold (which also varies by dash number).

As to what will happen if you remove the reset controller, I don't know. In general, leaving an input to a processor 'floating' is a big No-No (ref 'Rowan and Martin's Laugh-In). However, many processors have internal pullups on critical lines. Some even have their own internal reset controllers. The fact that the processor works with the reset controller removed is a good sign.

As I have stated, monitors are not built on a 'cost plus' basis. I am certain the designer believed it necessary to have a reset controller. Whether or not they are correct is another matter.

PlainBill

[sceva]

Re: No power on a Acer AL1916

Thanks for the update. I agree that it is usually best to replace parts, as the reason they are there may not be initially apparent. Although... if designers and builders didn't make mistakes, we wouldn't have much to repair?

[PlainBill]

Re: No power on a Acer AL1916

Thanks for the update. I agree that it is usually best to replace parts, as the reason they are there may not be initially apparent. Although... if designers and builders didn't make mistakes, we wouldn't have much to repair?

That is a point I have just been thinking about. Sometimes an improved design makes parts unnecessary. Designers don't always read the application notes carefully. It is not beyond the realm of possibility that the reset controller is there because the lead designer KNEW this line of processors always required one. It is also not beyond the realm of possibility that there was a design error on the reset controller.

PlainBill