Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
OK I can see on the pads where the capacitor leads have been ripped out of the solder, on PC58 it looks like one lead is actually still half there.
You need to put in new capacitors and then continue troubleshooting from there if that doesn't fix the problem. Make sure the capacitors are Low ESR too.
Might pay to take some more photos of your board and upload, in case there are any other problems like that.
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
verified by some other pictures that I found on eBay the two of the "can upright" capacitors are missing from this board. Not sure if that would affect the operation of it or not.
Computer and Small electronics troubleshooting and repair
Could not having those two caps on the board cause problems?
Yes, if they could get away with not having them there and save money, they would.
I don't know exactly what would happen, my guess is without those capacitors to filter the ripple\noise from the switching converter, there are voltage spikes coming through which trigger OVP (Overvoltage protection) on those rails and the controller is shutting down.
In any case, without those capacitors, the rails will be severely out of specification and won't work to power anything properly. Those capacitors NEED to be there. Put new ones in. It may just solve the problems.
Do you know how they went missing to start with?
"Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
-David VanHorn
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
I'm guessing who ever ripped this machine apart did a real bad job. It came in a box like a pile of junk. The fan was destroyed so I have to replace that along with some missing cables.
Computer and Small electronics troubleshooting and repair
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
I don't know, without power to the other rails etc it may be a bad idea, causing more damage.
If there are no shorts on +3VPCU and +5VPCU, and you have connected the correct capacitors properly (can you show photos?) then perhaps the PU3 chip has failed. Perhaps it failed due to missing capacitors, or perhaps it already failed and in doing so it blew those capacitors which is why they were missing.
Another thing which could cause no power on either of those rails is if the high-side MOSFETs on both rails (PQ13, PQ14) have gone open circuit. Seems unlikely both would die at the same time though.
If you have a scope you could see if any of the switching FETs are getting gate drive.
"Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
-David VanHorn
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
-check pin3 pu3 as reference IC in good condition
-check voltage pin12 and 19 pu3, if high means over-voltage protection
-on post # 38, if the low resistance short circuit?
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
Agent 24,
I am a little confused at this point, because on pg 37 of the schematic, it is showing that the charger system is separate from the rest of the circuits. What I mean is that the adapter or battery is connected to the charger and that is what supplies the VIN at 5.48 amps. All I am concerned about for now is that I can get the battery to charge. I am not worried about supplying voltages to the rest of the computer.
Computer and Small electronics troubleshooting and repair
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
The charger IC has VIN supply but it won't do anything unless it has the ACOK signal as well (among other things). That signal comes from the +3VPCU rail, and we know that isn't coming up.
TEMP_MBAT_C line from the battery also requires a pullup from +3VPCU rail.
Without that main supply running, nothing else is going to happen.
"Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
-David VanHorn
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
I am starting to wonder if it is even worth trying to troubleshoot this anymore. If pu3 has failed, I have no way of replacing it. I was hoping that it might just be a short somewhere on the board that I can find and fix. Like I said in one of my first posts, I have experience with bigger components that I can actually see whit my own eyes. When it comes to smaller ones I am kind of at a loss.
I know that power is getting into pu3, it just seems that nothing is being outputted from it. I also don't know if it is turning it's self on or not.
PQ13 pin 5 and PQ14 pin 5 does have power as it comes from the VIN line. After that is where it gets confusing because PL3 and PL4 has no voltage in or out of either one.
Computer and Small electronics troubleshooting and repair
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
Did you check the things meritosari mentioned in post #53?
The VIN will get to PQ13 and PQ14 drain pins, but if PU3 is not sending gate drive to turn the FETs on, no current will flow through them.
PU3 is the controller and driver for what is a switching-type power supply so it actually turns the FETs on and off rapidly. This means short bursts of power from the VIN line go through the FETs, enter the inductors PL3 and PL4, and are filtered by the capacitors which were missing.
Changes in load are sensed by PU3 and compensated for by changes in the duty cycle of the gate drive waveform to the FETs, which keeps the output voltage constant under varying load conditions.
"Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
-David VanHorn
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
Good Day., if your problem still there, you can try to replace the ec chip NOVUTON NPCE791LA0DX if you have a working spare..its likely this chip is easy to damage..just try..
Re: Acer Aspire One D270 Netbook has no Power or Battery charge Indicator
I don't get any of the voltages that you mentioned from pu3, so I am under the impression that PU3 is dead, with that being said I don't think there is anyway that I can fix this board and bring it back to life. So now I am really stuck on what to do. If anyone has any suggestions I would really like to here them.
Thanks
Tom
Computer and Small electronics troubleshooting and repair
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