Acer Aspire 3100 BL51 Laptop POST Fail

[Per Hansson]

Hi, I've got a friends laptop here
Some Acer Aspire with a Phoenix BIOS, get no picture on LCD or external VGA so I put in a MiniPCI Port80H POST Debug device

It fails on 55: "Enable USB Devices"
So I started removing stuff, like the USB Camera in the LCD panel etc
Untill I ended up with what you see in the picture

So, with just mainboard, CPU and RAM connected it still hangs on the same postcode, any ideas? A new mobo is more expensive than a new Laptop! (Acer part; MB.ABE02.001)

Also attached is the list of Postcodes, the ones with questionsmarks I did not have any info on in my little manual that came with the postcard...

[Wizard]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

What you find is that acer notebooks is a dump. Hence the lowest selling prices compared to decent models. I had one older model (Celeron 800 soldered down model) and all the plastic bits that holds the hinge is all broken up. The Aspire One is constructed similarly, had seen the ones in pictures all apart. No metal reinforcing structure that was common back in the early days of notebooks (read: compaq LTE, aero etc).

Cheers, Wizard

[370forlife]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

maybe one of the usb ports are shorted

[Per Hansson]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

Yea, I was thinking that too
There is also a soldered on Secure Digital Card reader on the mainboard

Plus the part that sticks out with two USB ports on it also has the power on button
This is a detachable PCB board, if it is the culprit I could buy one on ebay for $10
But I have no idea if that is the thing causing it of course...

How would I go about measuring the USB ports?

[370forlife]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

you mean measuring voltages? I believe the are suppose to be 5v and something else, not sure.

[i4004]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

so if i, for example, short the usb power pins on the acer laptops, they won't boot?
wouldn't that be visible by visual inspection(ie good vs broken usb connector)?

is that so, or should the attention be at the bios chip?

what's that minipci debug device u use?

[Per Hansson]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

you mean measuring voltages? I believe the are suppose to be 5v and something else, not sure.

Yea yea, I figured that much
I was just wondering if there was any advanced testing that could be done...

i4004; http://cgi.ebay.com/ws/eBayISAPI.dll...m=180310114763

[kc8adu]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

i have had more than 1 board come in with a no post issue that had a mashed usb causing it.

[Wizard]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

do you mean mashed USB port or chip blown?

FYI: to others, USB is tied directly to the southbridge chipset. The usb 5V is via a resettable thermal fuse. Some cheap boards don't have it or one time fuse.

Cheers, Wizard

[Per Hansson]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

Ok, the board has 3 USB ports
All 3 read 5.11v when the system is running and they all seem properly grounded (they are a bit higher when the system is soft off)

The two USB ports on the "switch board" as Acer calls it do not read anything at all on the data lines against ground.
However the lone USB port on the mainboard itself reads ca 2.33v on both Data lines, which is normal, no voltage at all or voltage on the data lines?

Also for all USB ports if I give the system some power, and then remove the power adapter and measure between 5v and ground the multimeter gives me a short beep as the residual current stored in the capacitors on the mainboard is discarged into ground

[i4004]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

i doubt shorted data lines would cause laptop not to boot(if they were shorted, it doesn't seem they are), overall it seems problem is not with ports.

like i said originally is there anything you can do to test bios?

ie perhaps bios is stopping at usb init not because usb ports are shorted(as they're not) but because bios is damaged at that address....
also, if usb was shorted i would expect it not to post at all...(incase it's the mobo without protection for 5v for usb ports...) and you have at least beginning of post.

could also be southbridge...

anyway, looks pretty grim for easy cure to be found.

[Per Hansson]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

No, the BIOS can't be tested
It's a surface mount thing with very tiny legs and no SPI header to program it in circuit...

Tried connecting a MS Intellimouse Explorer 3.0 to the USB ports
It did not turn on it's red led inside it
Of course this could mean nothing, my Asus Maximus Formula mainboard does the same thing; USB powered devices are turned on during post on init USB devices

[i4004]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

tell your friend to skip acer in the future.

my sister's aspire just seems ridiculous in comparison to my lenovo.
it has a weird overheating problem that seems to be all but usual thing for aspires of that series.
and the hinge...oh god.

to troubleshoot it further you would probably need service manual, if such stuff exists for that laptop anyway...
then measure and measure and establish it's some chip you can't desolder anyway...huh...

how old is it?

[Per Hansson]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

Managed to find which pins to short to power on the board without that external thing with the power buttons and 2 USB ports

Same thing tho, POST stopped at 55: "Enable USB Devices"
Anyone know if I should see ca 2.33v on both Data lines of the USB connector to ground? (since now I only have one USB port left when the system is trying to POST)

[NxB]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

Signal voltage should be 3.5v

[Per Hansson]

Re: Acer Aspire 3100 BL51 Laptop POST Fail

NxB; Thnx for the info
I've now spoken to the owner of the laptop
Apparently it died when he had it connected to a racing bikes digital box for checking laptimes etc...

So it's either the USB port or the southbridge I guess (I assume USB is included in the southbridge and not separate)
At this stage I guess I can just take out the soldering iron and start removing stuff untill it boots or I have a bare PCB :P