good morning all,
i purchased a used dell e6540 laptop used 10 months ago from a vendor on ebay. intel i-7 processor, 16 gb ddr3 memory, 256 gb ssd., mobo la-9413p (rev 1.0 dated 2014-08-04). i've inflicted no damage on it since purchase but its past is unknown. starting 2 weeks ago it began to fail to boot (initially 9 of 10 boot attempts failed, now 10 of 10 fail). there was no new hardware or software added (i was using as a kodi video server). the post process doesn't complete and booting no longer displays the dell logo screen - screen remains black with no backlight. some other observations:
1. power + f2/f12 no longer provide a break to the boot process. when the problem first started i did manage to run the f12 diagnostics (including extended memory diags) and everything checked out ok. i have that output.
2. the dell power supply has a light ring at the end of the plug that goes into the laptop. it remains lighted when powering the laptop. based on research that indicates that there is not a short on the high side power. if there was a short on the high side power the ac power supply shuts off and the blue ring no longer illuminates.
3. during the boot up processes there are no beeps, no errors or messages displayed.
4. the keyboard lights up when you press a key but not the small dot on the caps lock key when its engaged
i did some minimally invasive troubleshooting steps, the most relevant are listed below:
1. i changed the cmos battery which should clear cmos memory. rebooted and the same result. machine does not ask for new date/time which it should.
2. i removed the dvd player, hard drive, wifi card and there is nothing else connected to it. rebooted and the same result.
3. holding the "fn" key + power on runs a set of dell diags. the result i get is the battery light flashes white. per the dell user manual that indicates a "Memory failed to initialize or memory is unsupported." condition. it does not specify which memory (ram, bios, etc.). no new memory has been installed.
4. swapped memory with a known good e6540. the known good e6540 boots with the failed e6540's memory, and the failed machine still fails to boot.
5. the memory sticks in the failed e6540 do not feel hot to the touch so if a power problem it isn't a power short from a higher voltage. i believe that condition can occur when the first of two mosfets in series shorts.
6. i removed both sticks and holding the fn key + power on results in a different set of flashing led lights indicating no memory was found. so the machine can still determine the hardware attached to it.
at this point i have disassembled the machine exposing the mobo. its an impressive pile of small screws and plastic parts.
my asks:
1. any thoughts on a possible diagnosis given the data above?
2. i have a pdf schematic and a brd file for a similar mobo (the la-9411p). i couldn't find the exact schematic on www.badcaps.org or www.alisaler.com. i'm hoping the 9411-p is close enough. ditto the brd file. if you happen to know where i might locate the files corresponding to the la-9413p mobo or if you think the ones i have are close enough, please let me know.
3. this is my first foray into troubleshooting individual mobo components. i've watched a number of vids but i'm at that 'you need to take the first step' point. suggestions on where to start or a structured methodology to follow?
4. i haven't upgraded the bios on this machine. i have on the 2 other e6540's i have. if installing a clean bios is the next step i have a ch341a usb programmer that i could use to flash the same E6540A27 bios i flashed to the other machines but am not sure what element name that would be in the brd file (so i could locate the bios physically on the mobo). i'm still exploring the basic functionality of allegro and can do some basic searches but with my limited use of allegro so far i've been unable to identify where the bios chip is located.
it would be cheaper to buy a replacement mobo on ebay but thought this might be a good opportunity to learn a little more about troubleshooting methodologies at the board component level.
thanks!
i purchased a used dell e6540 laptop used 10 months ago from a vendor on ebay. intel i-7 processor, 16 gb ddr3 memory, 256 gb ssd., mobo la-9413p (rev 1.0 dated 2014-08-04). i've inflicted no damage on it since purchase but its past is unknown. starting 2 weeks ago it began to fail to boot (initially 9 of 10 boot attempts failed, now 10 of 10 fail). there was no new hardware or software added (i was using as a kodi video server). the post process doesn't complete and booting no longer displays the dell logo screen - screen remains black with no backlight. some other observations:
1. power + f2/f12 no longer provide a break to the boot process. when the problem first started i did manage to run the f12 diagnostics (including extended memory diags) and everything checked out ok. i have that output.
2. the dell power supply has a light ring at the end of the plug that goes into the laptop. it remains lighted when powering the laptop. based on research that indicates that there is not a short on the high side power. if there was a short on the high side power the ac power supply shuts off and the blue ring no longer illuminates.
3. during the boot up processes there are no beeps, no errors or messages displayed.
4. the keyboard lights up when you press a key but not the small dot on the caps lock key when its engaged
i did some minimally invasive troubleshooting steps, the most relevant are listed below:
1. i changed the cmos battery which should clear cmos memory. rebooted and the same result. machine does not ask for new date/time which it should.
2. i removed the dvd player, hard drive, wifi card and there is nothing else connected to it. rebooted and the same result.
3. holding the "fn" key + power on runs a set of dell diags. the result i get is the battery light flashes white. per the dell user manual that indicates a "Memory failed to initialize or memory is unsupported." condition. it does not specify which memory (ram, bios, etc.). no new memory has been installed.
4. swapped memory with a known good e6540. the known good e6540 boots with the failed e6540's memory, and the failed machine still fails to boot.
5. the memory sticks in the failed e6540 do not feel hot to the touch so if a power problem it isn't a power short from a higher voltage. i believe that condition can occur when the first of two mosfets in series shorts.
6. i removed both sticks and holding the fn key + power on results in a different set of flashing led lights indicating no memory was found. so the machine can still determine the hardware attached to it.
at this point i have disassembled the machine exposing the mobo. its an impressive pile of small screws and plastic parts.
my asks:
1. any thoughts on a possible diagnosis given the data above?
2. i have a pdf schematic and a brd file for a similar mobo (the la-9411p). i couldn't find the exact schematic on www.badcaps.org or www.alisaler.com. i'm hoping the 9411-p is close enough. ditto the brd file. if you happen to know where i might locate the files corresponding to the la-9413p mobo or if you think the ones i have are close enough, please let me know.
3. this is my first foray into troubleshooting individual mobo components. i've watched a number of vids but i'm at that 'you need to take the first step' point. suggestions on where to start or a structured methodology to follow?
4. i haven't upgraded the bios on this machine. i have on the 2 other e6540's i have. if installing a clean bios is the next step i have a ch341a usb programmer that i could use to flash the same E6540A27 bios i flashed to the other machines but am not sure what element name that would be in the brd file (so i could locate the bios physically on the mobo). i'm still exploring the basic functionality of allegro and can do some basic searches but with my limited use of allegro so far i've been unable to identify where the bios chip is located.
it would be cheaper to buy a replacement mobo on ebay but thought this might be a good opportunity to learn a little more about troubleshooting methodologies at the board component level.
thanks!
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