*SOLVED !!!* AAone doesn't power on:lights flash and dim out

Hi everyone!

It's my first post after reading this forum for more than a week.

My Aone (8.9", 160GB,XP) just decided to refuse to turn on after it was left OFF to recharge the battery. I have tried everything that has been mentioned on this forum: press power button for 30 sec with AC and battery removed; plugged them back-nothing. I've even tried the BIOS reset described here: http://macles.blogspot.com/2008/08/acer ... overy.html

It was obvious it wouldn't work since it doesn't power on, but I tried anyway..

The symptoms are similar to the ones described here:
viewtopic.php?f=24&t=12285

When I connect the AC adapter, the battery and power lights are coming on for a brief second and then they just dim out. Power button is not responsive.

I have swapped both the battery and the AC adapter with known good ones from my other Aone which works perfectly, but it does exactly the same thing.

I simply refuse to give up on him and I am wondering if anybody has done any component level repairs on the Aonemotherboards. All I need is a hint!

I have checked for cracked solderings and fried components, but couldn't find anything obvious..

I have managed to get the SERVICE MANUAL, but it doesn't include the electronic diagram.

I don't want to break any of the forum's rules by posting the link for the other members to download it, but if the moderators will allow me, I will.

Sorry for the long post, but I need an educated opinion and some help.

Thank you,
John.

 

Re: AAone doesn't power on:lights flash and dim out

Here is the Motherboard schematic; http://vassyl.net/work/acerone/aspire0nemb.pdf (Thanks to Mali)

I am currently working one MB with this problem, but I have not located the component which causes this behavior. So most likely you will need to replace the motherboard.

PM me if you want prices.

 

Re: AAone doesn't power on:lights flash and dim out

Wow great, jerryt !!! Thank you for the schematics, that should give me something to start with.

Well in this case, I wouldn't probably break any forum rules if I post the link for the Service Manual,just in case someone else needs it:

http://rapidshare.com/files/193648061/A ... _Guide.pdf

Do you mind if we keep in touch about our findings on this issue? I'll keep you updated with my progress. Replacing the motherboard will kill all the satisfaction of reviving the little guy

Cheers!!!

 

Re: AAone doesn't power on:lights flash and dim out

Everything kinda points to PU1 (charger page on schematics). It is a specialized IC for battery charging. It is in QFN package which is prone to failures due to lead-free solder. I'd put the heat gun on it first.

Good news is that most of the components in the power module are available online for super cheap prices!(<$1/each).

 

Re: AAone doesn't power on:lights flash and dim out

jerryT any progress on your aaone?

I have found something, but now I have to trace the cause of it..

Let me know if still interested and maybe we can pinpoint the defect by putting all the info together.

 

Re: AAone doesn't power on:lights flash and dim out

My motherboard would not power on at all at first. I was probing the board with power attached, then power came on and PC119 melted in half. Replaced PC119 and board will power on until lcd gets power then shuts off. If I get the board to enter the Bios Recovery, the power switch will flash indefinately. Freezing or heating the board has no effect.

This motherboard appears to fail at a point during post where it has to supply power (5V?), I am out of ideas.

 

Re: AAone doesn't power on:lights flash and dim out

Mine was doing the same thing. Turns out I had it plugged in, but it didn't charge. I was using a multi-plug adapter (the same one I've been using for months) and had the plug firmly seated in the outlet, but it still thought it wasn't plugged in. Fixed it by plugging it into an outlet without the adapter and it charged. Don't know why it didn't work, but now all is fine, even in the the multi-plug. Just some weird glitch, I guess.

 

Re: AAone doesn't power on:lights flash and dim out

Thanks JimK, we wish it was that simple in our case...hehehe

jerryt, I haven't found anything fried on mine, but all it does is the battery charge LED and power LED come one for half-second and then dim out. Thanks to the schematics (thank you Mali) I have managed to check the charging module (page 27), the System 5v/3v (page 28) power and everything is correct (voltages are all ok). I have tested the ACin on PU1 (page 25) and it works beautiful, detecting when AC is connected or disconnected.

The only problem I could find is D/C# (page25 again) which goes straight to the Source of PQ21 (pin 2) and pin 5 on PQ20. It reads LOW (0.3V) instead of High (>1V) which blocks the PQ21 and PQ20, therefore the charging of the battery is disabled ( BAT -V is zero). I traced the D/C# to the pin 25 of the U9 (page25) which is the Embedded Controller and that's where I am right now. I am not sure if the controller is forced into this state by some condition or if the SPI Flash (U8) is faulty. Knowing the history of BIOS getting corrupted after recharging the battery on these models, I'd think the the SPI Flash/BIOS chip is bad (or corrupted beyond recovery..).If you can verify my work, maybe you can find something that I missed, jerryt.

Mali looks pretty knowledgeable,too and it would be nice if he can give us a hand with this issue.

PS: I have managed to source a pre-flashed chip, but I really wouldn't spend $25 without a solid suspicion that my chip is bad...

 

Re: AAone doesn't power on:lights flash and dim out

You are way farther along then me. But I agree that a known good bios chip is an excellent approach. Newfutile on this forum (viewtopic.php?f=50&t=15917&start=10) has the Bios chip programer but he does not know the "Offset" for where to start the write. He needs to read a good chip to get the offset. Also there are places that will remove and program your bios for 19.99 (http://bios-repair.co.uk/bios/spiflash.html). We could split the 25.00 and have Newfutile read and program a few bios chips for us. Win, Win, for everyone. (I can send two bios chips to him, but their status is unknown).

 

Re: AAone doesn't power on:lights flash and dim out

Well, actually that british firm is my source for a new chip. They quoted me 12.49 pounds (about $25) for a new pre-programmed chip...

But what you're saying makes sense,too. I'll have to check a few more things before I commit to anything, just to make sure it's not a waste of time and...hehehe..more time $$$.

 

Re: AAone doesn't power on:lights flash and dim out

The offset is described in the datasheet for the chip, I came across the pdf on the net while I was checking different things about this motherboard.

If it will help, I can probably find it again.

 

Re: AAone doesn't power on:lights flash and dim out

I am sure it would make his day.

 

Re: AAone doesn't power on:lights flash and dim out

jerryt, I think you still have a faulty component in the power module. When the LCD tries to turn on it sucks a lot of juice (the backlight does) and that's when your bad component kicks in. When you shorted out the power and fried PC119 you might have damaged something else (PL1-next to it) for example. Do you even remember what pins have you shorted out??

Myself, I'm just stuck not being sure if it's actually a bad BIOS chip or something else that keep eluding me. I am really irritated by this now :evil:

Anyway, I think this thread would fit better in the HARDWARE HACKS AND MODIFICATIONS since those guys are into this stuff.

I'll just post them a link to here maybe they pitch in an idea or two.

 

Re: AAone doesn't power on:lights flash and dim out

I have tried booting without the LCD and it still shuts down. I never shorted anything, I got this as a non working motherboard and it had no signs of life at all. Until I was probing the battery connections and it came alive with PC119 shorting.

My theory is PC119 was shorted and pulled all the power to ground (Original complaint board dead), until it melted. Now charging circuit works fine, responses to power switch, will enter Bios Recovery, but Shuts off during post and also never completes the bios recovery.

I agree that it acts like some power circuit is overloaded.

If you could suggest specific multimeter checks that would be a big help, because I can not determine the checks myself from reading the schematics.

 

Re: AAone doesn't power on:lights flash and dim out

jerryt, we can compare our voltages to some point, because mine doesn't want to power on, therefore some voltages will not be the ones you may want, BUT yours should be the ones that are correct- before you try to power on. I'll bring the schematic with my notes on it, scan it and PM it to you (I'm at work now and I left it at home).

In the meantime it would be interesting to check a few that I know (page 27- charger):
- pin 4 on PQ2....I have 9.55V
- pin 5,6,7,8 on PQ2 (=Vin)....19.5v
- pins 2+3 on PQ20...19.4V
- pin 5,6,7,8 on PQ3....I have 0V
- pin 2 on PQ21...I have 0V
- terminals 2 and 3 on battery connector (with battery connected,AC in, but power off)....2.36V

All these measurements to be done with battery connected,AC in, power OFF.

Just add your voltages with red next to mine and let's compare to see if we get somewhere with it. Tomorrow I'll get the rest of them

 

Re: AAone doesn't power on:lights flash and dim out

Oh, and PC119 that got fried on your mobo is a 10 microF/25v non-polarized. Make sure you've replaced it with the correct one...

 

Re: AAone doesn't power on:lights flash and dim out

If you're still under warranty, don't bother searching. That happened to me a few weeks ago. I sent it to Acer it was returned to me within a week, working fine. Also, bear in mind that the more times you send it to repair, the most likely you are to be sent a brand new one at some point!.. :lol:

 

Re: AAone doesn't power on:lights flash and dim out

Thanks simbeb, but if it was still under warranty, I wouldn't have wasted my time on it...

Therefore, the show is on, I gotta find the culprit

It's exciting, I can't deny it

If we do find the issue, it will be a great contribution to everyone, since sooner or later, the fault it will occur to more of these AAones after the warranty is long gone. Who would shell out $150 bucks to replace the board for an 80 cents faulty component???

 

Re: AAone doesn't power on:lights flash and dim out

@ X33 I have good motherboards, so outline all the checks you can think of and I will test working and non working motherboards side by side this Friday.

 

Re: AAone doesn't power on:lights flash and dim out

Sounds like a good plan, jerryt!