Ideapad 310 power questions

[Draconian]

Hi all I have a question about power rails and peripherals

So I have a Lenovo ideapad 310 which has died, had trouble starting but would sometimes start and work fine this has progressed to not working at all.

Now it has no display and no light on the Cps lock/keyboard also external mouse doesn't light up.

The fan does spin.
Main power light is on.

What I've done.

I've completely stripped the laptop apart from the soldered on 4GB of ram.
I've reset the BIOS and tested the battery.
Tested the power supply and used another.

The strange part to me is that when i test the USB ports they are receiving 5v so that power rail is working, but no lights on any peripherals.

The crux of my question, why would the fan spin up and the USBs get power but no lights on the peripherals, do they need a signal to utilize the power provided?

Any suggestions for whats wrong with the board or what the next best steps are would be great. CPU, I/O chip maybe a controller chip just seems odd to me that i get fan spin and power on the 5v rail but no lights.

Thanks for reading.

 

[coffee]

If you really want to pursue this then look around and see if you can get a schematic for the MB. Otherwise its probably going to need a new MB in it.

You can kinda guess around - pull the MB from the laptop and inspect for damage / water / burned components.

Does an external monitor/keyboard/mouse work on it???

 

[Draconian]

Hi thanks for your reply.

No, i'm using an external mouse and tried a keyboard also whilst it's bare bones to see if there's been any change.
I did also try a VGA and HDMI Monitor to see if I could get image an image, no joy.

I've now also tested the power pins to the LCD there are two live pins showing the same voltage as the charger. This seems correct to me.
In addition one is connected to a 3v rail i assume data or some such. like you say without a schematic its guess work. I'm more looking for opinions on what this could be and whether it's worth pursuing further, why I get correct voltage to the USBs, fan and display but no backlight, no lights on... but do get the fan and main power light.

There is no discernible liquid damage or blown components it looks near brand new inside even under the microscope.

Could the on-board RAM be faulty... I've plugged in a stick of DDR4 would the computer ignore the faulty on-board RAM and load using the working RAM or does it default to the on-board RAM first?
If so would reflowing the on-board chips be worthwhile, if it's not likely to solve anything i don't want to go down this road as they're super close to the detachable ram slot.

Any help appreciated

 

[coffee]

Hi thanks for your reply.

No, i'm using an external mouse and tried a keyboard also whilst it's bare bones to see if there's been any change.
I did also try a VGA and HDMI Monitor to see if I could get image an image, no joy.

I've now also tested the power pins to the LCD there are two live pins showing the same voltage as the charger. This seems correct to me.
In addition one is connected to a 3v rail i assume data or some such. like you say without a schematic its guess work. I'm more looking for opinions on what this could be and whether it's worth pursuing further, why I get correct voltage to the USBs, fan and display but no backlight, no lights on... but do get the fan and main power light.

There is no discernible liquid damage or blown components it looks near brand new inside even under the microscope.

Could the on-board RAM be faulty... I've plugged in a stick of DDR4 would the computer ignore the faulty on-board RAM and load using the working RAM or does it default to the on-board RAM first?
If so would reflowing the on-board chips be worthwhile, if it's not likely to solve anything i don't want to go down this road as they're super close to the detachable ram slot.

Any help appreciated

The 3v rail could be a sense circuit. Sense circuits tell the particular rail to turn on or stay off.

This is quite a job to do and it would be better to just replace the MB IMHO. However, If you want to go ahead, I would look at the IC's on the board and look them up. Find where VCC/VIN pin is on these chips and measure for the correct voltage. If your not getting voltage to a particular IC then it may not be told to turn on because of a sense line or there is a short. This will take a while as you do not have a schematic.

Check for a short - Power off - Take your meter and put it in diode mode, Red lead on ground. Black on pin of component. If its shorted to ground your going to get a very low reading or non at all.

Reflowing I would not think is an option at this point. If the board was really dirty and abused I would entertain that but when you describe it as clean. Reflowing might just take you down a rabbit hole

As for the ram, I would leave it alone. See if the ram is getting approx. 3.3 volts or so.

 

[Draconian]

Thanks I'll check the RAM and top pins of any obvious IC's.
Didn't think there'd be a short as i have fan and main power + the 5v rail is ok, i'll check some other places and see if there's a short on one of the other power rails (not that i'll know what its for : / ), thanks for the help so far.

My only reason for continuing to this point is the only currently available replacement MBs are in the US and i'm UK based. : (

 

[Porthos]

My only reason for continuing to this point is the only currently available replacement MBs are in the US and i'm UK based. : (

Replace computer.

 

[coffee]

Thanks I'll check the RAM and top pins of any obvious IC's.
Didn't think there'd be a short as i have fan and main power + the 5v rail is ok, i'll check some other places and see if there's a short on one of the other power rails (not that i'll know what its for : / ), thanks for the help so far.

My only reason for continuing to this point is the only currently available replacement MBs are in the US and i'm UK based. : (

How about you post the model number on that laptop and some hardware info. I have a bit of time today I might be able to get a schematic for you.

 

[Draconian]

if possible that would be ace.

It's a Lenove Ideapad 310-15ABR with an AMD A10 processor.
The motherboard ref number is CG516 NM-A74
rev 1

 

[coffee]

if possible that would be ace.

It's a Lenove Ideapad 310-15ABR with an AMD A10 processor.
The motherboard ref number is CG516 NM-A74
rev 1

Ill keep that in mind. Im always looking around for schematics and Ill just add that to my list.

If your going to get into surface mount repair then you might be interested in the program "Boardview" . I use it all the time for my repairs.

 

[Draconian]

Would that be Paul Daniels Board View? I've come across this program in my learning to date, I've not purchased it yet but it looks very useful.

If you come across the schematic on your travels I'd appreciate a link or copy very much.

Thank you for all your help.

 

[coffee]

I repaired my ideapad and it is now working fine. I did it without a schematic and about 2 days of studying motherboard layouts and troubleshooting. Its very interesting. Infact, I doubt I need a schematic anymore really for most common repairs. Here is a link for you:

https://www.youtube.com/channel/UCooKQlg-HZ0PFAPc4Ymg3RA/videos

Extremely useful information from this Gentleman. I urge you to watch a lot of his videos. You will pickup a lot of useful information.