Dell Latitude 7410 dead and amber light as long power button is pressed.

[Andreasbest]

Hello.
I received a bios locked 7410 with 25Q256JVEQ ,i dump the bios, unlocked it and flash it back, since then the laptop has no life signs at all except amber led on for as long the power button is pressed, nothing else.
Fact #1 i was unaware that 25Q256JVEQ is 3.3v and i used a 5v CH341A to program it, not sure if the chip got damaged but since then i can read it and write it normally, doesn't seem dead.
Fact #2 i modded the CH341A to 3.3v, same results with programming though, nothing changed.
Fact #3 i tried hard reset with cmos/main battery disconnected and power button pressed but no luck
Fact #4 i tried all bios, the locked, the unlocked and a few i found on this subforum, no luck either

Any advises? I suspect i killed 25Q256JVEQ with 5v CH341A but how it's possible to work on read and write?

Thank you in advance!

[Andreasbest]

Found out that 7310 has exactly the same board, LA-J261P, so i replaced from the fully working 7310 the bios chip UC5 and two other winbonds UT2 and UT9 but still the same behavior.
Seems like something serious occurs here
Schematics here https://www.badcaps.net/forum/troubl...67#post3170367

[rddube]

If you can read and write from the chip it is still good (do a verify to make sure it stores what you wrote). Try a few things. Did you do a full reset of the bios before trying to turn it on - remove CMOS battery and short the terminals (don't forget to remove the internal battery also before you work on anything). Report back.


If that doesn't work, did you make a copy of the original bios? What happens when you flash the original dump. does it boot up? If yes, then you don't have the right unlocked bios version.

[Andreasbest]

If you can read and write from the chip it is still good (do a verify to make sure it stores what you wrote). Try a few things. Did you do a full reset of the bios before trying to turn it on - remove CMOS battery and short the terminals (don't forget to remove the internal battery also before you work on anything). Report back.


If that doesn't work, did you make a copy of the original bios? What happens when you flash the original dump. does it boot up? If yes, then you don't have the right unlocked bios version.

Hello!
I have done all these, written in facts #.
What i dound out lately is that this amber light of death is very common issue lately in Dell.
Happens on all series, inspiron, xps, latitude and Precision.
In all cases solution is either motherboard replacement or cmos reset.

Gonna check what motherboards are on the other dell that suffer this error.
Sad to say but Dell is a bad company anymore.

[lotas]

The problem may be in uninstalled status registers; when reading the original dump, you need to know exactly which status register was written and the same one should be written when writing a copy of the dump.

[Andreasbest]

I swap the bios chip with a working 7310 and 7310 works great with the bios chip from 7410, so the problem is clearly NOT in bios dump or bios chip.

Made some more research regarding the solid amber light when power button pressed on Dell, seems to occur in desktops too.
On laptops i checked 5 different models, all motherboards are different to each other, so it's probably not motherboard component damage but something to do with Dell firmwares, perhaps EC got corrupted or BIOS indicates "something" is wrong and won't boot?

[Andreasbest]

Left it on charge all night, no response.
On morning i had the same behavior.
DO you have any ideas or proceed in MB replacement?

[Andreasbest]

Power consumption very low (with battery attached)

[diamesa]

Did you found anything else? I have the same problem in a series 5000. There are at least a couple more in the forum...

In my case, I probed the BIOS chip but there was no SPI activity going on, which led me to think that the issue is happening before CPU reads from BIOS (if that makes sense) could it be that the MB is not powering the CPU ? Does that makes sense? I'm not familiar with what the normal power up sequence is....

[Sephir0th]

It should be clear that when a known good BIOS doesn solve the issue, then the fundamental assumption, on whatever it is based, is wrong or it has been solved already and something has happened while the repair attempt.

The only useful approach here is to get more informations about the board behaviour. Right now we have nothing.

Current consumption points to a big hang in the early power up sequence, including battery not charging. Most likely stuck between ON/OFF# / PM_PWRBTN or PM_SLP_S5#/S4#

tl;dr: Either you start to "really" dig in or, you need to stay at troubleshooting simple short circuits. But this is insufficient.

[Andreasbest]

It should be clear that when a known good BIOS doesn solve the issue, then the fundamental assumption, on whatever it is based, is wrong or it has been solved already and something has happened while the repair attempt.

The only useful approach here is to get more informations about the board behaviour. Right now we have nothing.

Current consumption points to a big hang in the early power up sequence, including battery not charging. Most likely stuck between ON/OFF# / PM_PWRBTN or PM_SLP_S5#/S4#

tl;dr: Either you start to "really" dig in or, you need to stay at troubleshooting simple short circuits. But this is insufficient.

Motherboard was working great before patching BIOS for unlocking BUT it's proved now the BIOS is not the problem but probably the cause.
Except if it was just bad luck and timing.

Anyway, yesterday i received the QNF8 chip probe and i will give some more tries, just in case.
Also i have standby a fully working and updated 7410 with exact the same motherboard so perhaps i can compare all measurements.
I will start with 3.3, 5 and 19v and i'll report back.

This issue is huge, i found hundreds threads regarding this issue on several dell laptop and desktop so i hope we found a solution here.

[SMDFlea]

Found out that 7310 has exactly the same board, LA-J261P, so i replaced from the fully working 7310 the bios chip UC5 and two other winbonds UT2 and UT9 but still the same behavior.
Seems like something serious occurs here
Schematics here https://www.badcaps.net/forum/troubl...67#post3170367

The 7310 has different EC firmware, as far as i know.

[Andreasbest]

Exactly the same motherboard, same model, revision etc. Fully working with swapped bios chip.
What would the behavior if EC was different?

[rddube]

Exactly the same motherboard, same model, revision etc. Fully working with swapped bios chip.
What would the behavior if EC was different?

Not sure I understand you, if it's working with a swapped bios chip, just copy the chip and get on with it?

[Andreasbest]

Not sure I understand you, if it's working with a swapped bios chip, just copy the chip and get on with it?

Hello. I mean i got the BIOS chip from non working and solder it on the working motherboard and works great, meaning there is nothing wrong with BIOS or BIOS chip.

[3pka]

Guys did you find solution?

[rddube]

I swap the bios chip with a working 7310 and 7310 works great with the bios chip from 7410, so the problem is clearly NOT in bios dump or bios chip.

Made some more research regarding the solid amber light when power button pressed on Dell, seems to occur in desktops too.
On laptops i checked 5 different models, all motherboards are different to each other, so it's probably not motherboard component damage but something to do with Dell firmwares, perhaps EC got corrupted or BIOS indicates "something" is wrong and won't boot?

This is where I think you are wrong. The 7310 bios might not be right for your 7410 laptop - if it works in the 7310, doesn't mean it will work in the 7410. Try and get a 7410 dump, compare it to your original (use hex editor to compare). Pretty sure you have a bios issue.

[Andreasbest]

This is where I think you are wrong. The 7310 bios might not be right for your 7410 laptop - if it works in the 7310, doesn't mean it will work in the 7410. Try and get a 7410 dump, compare it to your original (use hex editor to compare). Pretty sure you have a bios issue.

My friend listen, i tried before to explain it. 7310 and 7410 have exactly the same motherboard, i have tried all combinations of flashing, no luck. Dell Support confirm 7310 and 7410 have the same BIOS.
Problem is on power supply rails but i still haven't managed to get some free time and research for it.
I'll start with 3v and 5v measurements, probably after Easter and update.
I really hope we manage to solve it, lots of Dell users suffer from this issue.

[rddube]

My friend listen, i tried before to explain it. 7310 and 7410 have exactly the same motherboard, i have tried all combinations of flashing, no luck. Dell Support confirm 7310 and 7410 have the same BIOS.
Problem is on power supply rails but i still haven't managed to get some free time and research for it.
I'll start with 3v and 5v measurements, probably after Easter and update.
I really hope we manage to solve it, lots of Dell users suffer from this issue.

Ok, well if you are convinced you have the right Bios, then the only other thing is that you have a hardware problem. "so i replaced from the fully working 7310 the bios chip UC5 and two other winbonds UT2 and UT9 but still the same behavior." means you used hot air I suppose - might have inadvertently unsoldered a resistance, capacitor, or something in the process. Check around those chips to see if you might have something that is misplaced. If you need help, post some clear and close photos of the areas you worked on. How would you rate your level of skill in using hot air ?

[vidvansh]

I am having the same issue with my laptops. I tried 2 laptops which were bio locked. I de-solder the bios chip on both, flashed them and then soldered them back. After that both the laptop are not turning ON, no activity.Amber light turns On when pressing power button. Can not figure out what could be the issue. On 1 laptop which is dell latitude 5400 i can see that i am missing a resistor near the bios chip. Don't know what to do next. On 2nd laptop which is 7410, i cannot see any missing part. Any guide on what can i try to fix those laptops.