HP Probook 6450b not powering battery light flashing 8 times

[robrock1]

Hello, i got this laptop for repairs, when you want to power it, the orange light just blinks 8 times and nothing else, i tried everything, i flashed a full bios dump, problem is still the same, i resoldered all the power ic and i reflow, nothing helps, any ideas?

[robrock1]

Re: HP Probook 6450b not powering battery light flashing 8 times

Ok i found the problem, its the adaptor enable signal that was interrupted, there was a liquid damage on the board, now its turning on but no display.

[lord]

Re: HP Probook 6450b not powering battery light flashing 8 times

Fix one error and discover another one.
You have all the voltages present?

[robrock1]

Re: HP Probook 6450b not powering battery light flashing 8 times

yes all the voltages are there, the current also jumps up and down through the different post levels then it gets stucked around 1 A, sometimes the capslock is blinking, i think the problem is from the intel chip i will reflow it and see.

[robrock1]

Re: HP Probook 6450b not powering battery light flashing 8 times

Ok i found the problem, the ic u14 that supplies power to the vga is damaged, it has no output. I removed it and took the power from the 2 mosfets that powers the cpu, i took the lgate and ugate and soldered it to the pins of the 2 mosfets for vga, running for some time now, i hope it will work out.

[masud]

Re: HP Probook 6450b not powering battery light flashing 8 times

i have the same problem in probook 4430s. please explain if you get result and specifically how.

thanks.

[robrock1]

Re: HP Probook 6450b not powering battery light flashing 8 times

Seems one mosfet got burned, i think because there is no feedback from the video card mosfet to the power ic so the power flow was to much, no what i did is i soldered a wire from cpu power coil to video coil and remove the video mosfets, then inside windows i disabled the other cores so so power consumption is low if not maybe the cpu mosfets will burn. In case it burns maybe have to replace the 2 mosfets with ones that can take more amps. I think even after the fix you shouldnt run any games or stuff that uses the video card a lot.

[robrock1]

Re: HP Probook 6450b not powering battery light flashing 8 times

Masud you have the orange flashing light or the no display fault?

[robrock1]

Re: HP Probook 6450b not powering battery light flashing 8 times

Check this images, follow the traces and make sure the signals are there.
I searched the net and nobody seems to have good answer for this battery light flashing problem.

I will give you some steps to check this should fix most of the problems.

First, very important to know: many hp models (some dell also) will not power on if the middle pin of the adaptor is not detected or the signal /voltage is wrong. Get the original working charger first before you mess up the board!

1. check your charging socket - replace it
2. Bridge the connection of the middle pin to 19v and check if it comes on
3. check if there is 19V on the mosfets and capacitors on the board, if not adp_en is missing to switch the first mosfets on.
4. If the OCP_A_IN signal that goes to the keyboard controller is missing, the flashing light will occur even when adp_en is there and you have 19v all over the board.

Maybe there is a trick to put 3.3v on the ocp_a_in or the selector output to simulate the adaptor is plugged in. In my case the trace for the limit_signal on the board was broken, because of water damage.

https://www.4shared.com/photo/vNVx2d...probook-1.html

https://www.4shared.com/photo/s8nYBR...probook-2.html

[crambook]

Re: HP Probook 6450b not powering battery light flashing 8 times

can you please send me the schematics for this model.

[dvd4me]

Elitebook 8440p - not powering battery light flashing 8 times

Hello,

I just finished solving this mystery that was puzzling me for the last 2 weeks. I just found this dead EliteBook 8440p with the blue battery LED flashing 8 times.
Not much info in the web, found some schematics, but the total lack of info regarding the meaning of the 8 times blink code was frustrating. Many "experts" were recommending to call HP...
I like to take the hard road...
I have tried to find info on the SMSC KBC1098 controller that powers up the board.
Nothing... the sequence of the signals that this IC is checking at power-up is a mystery.
I have re soldered the SMSC chip, use freezing spray to find some bad contacts on the board...
At some point the board was booting up but with no apparent reason. So all was fine for the rest of the board, voltages and the rest.
But then the board refuses to repeat the power up normally.

Now it all makes sense to me, because I found out that the first signal to check is the ADP_SIGNAL that comes from the adapter central pin, and it has to be at least 7-8V. In my case it was like 2.4V, very low.
Because of that, the OCP_A_IN signal was never getting high to 4.7V.
Maybe some resistor value changed on the board, because the adapter has the 14V on the middle pin...
SOLUTION that worked fine for me, soldered a 20kohm surface mount resistor, from the middle pin to the +19V, right on the power connector. It gets that OCP_A_IN to about 4.7V and it gets the right signal to SMSC KBC 1098

Now the EliteBook 8440pit boots correctly every time! no more 8 times battery led flashing.

Regards

[ere]

Re: Elitebook 8440p - not powering battery light flashing 8 times

Thank you very much master, you solved my issue.

[tormenta1026]

Re: Elitebook 8440p - not powering battery light flashing 8 times

Hello,

I just finished solving this mystery that was puzzling me for the last 2 weeks. I just found this dead EliteBook 8440p with the blue battery LED flashing 8 times.
Not much info in the web, found some schematics, but the total lack of info regarding the meaning of the 8 times blink code was frustrating. Many "experts" were recommending to call HP...
I like to take the hard road...
I have tried to find info on the SMSC KBC1098 controller that powers up the board.
Nothing... the sequence of the signals that this IC is checking at power-up is a mystery.
I have re soldered the SMSC chip, use freezing spray to find some bad contacts on the board...
At some point the board was booting up but with no apparent reason. So all was fine for the rest of the board, voltages and the rest.
But then the board refuses to repeat the power up normally.

Now it all makes sense to me, because I found out that the first signal to check is the ADP_SIGNAL that comes from the adapter central pin, and it has to be at least 7-8V. In my case it was like 2.4V, very low.
Because of that, the OCP_A_IN signal was never getting high to 4.7V.
Maybe some resistor value changed on the board, because the adapter has the 14V on the middle pin...
SOLUTION that worked fine for me, soldered a 20kohm surface mount resistor, from the middle pin to the +19V, right on the power connector. It gets that OCP_A_IN to about 4.7V and it gets the right signal to SMSC KBC 1098

Now the EliteBook 8440pit boots correctly every time! no more 8 times battery led flashing.

Regards

Magnificent solution thank you very much.

[dvd4me]

HP EliteBook 8540, 8440 battery light flashing 8 times

What a coincidence,
I found another EliteBook 8540 this time, with the exact same issue, blue light blink 8 times. I was searching with Google and I found my post, I had completely forgotten about this solution I found back then in 2017.
So I see the power connector with the 5 pins on the pcb side, middle is the center pin of the connector. Added a 10k resistor straight on some empty spot near the connector itself and now the voltage is around 9V. The battery is charging and computer turns on!
There must be some part on the motherboard changing properties in a similar way, since these 2 computers I found at 3 years interval happen to have the same 8 blink issue. Imagine how many motherboards have been changed for just a little resistor! Cheers!

[stingerchamp]

Re: HP Probook 6450b not powering battery light flashing 8 times

Awesome, indirectly you are fixing adapter every time

[befam77847]

Re: HP Probook 6450b not powering battery light flashing 8 times

FIX my HP 6540b

[befam77847]

Re: HP Probook 6450b not powering battery light flashing 8 times

Photo with notes

[stingerchamp]

Re: HP Probook 6450b not powering battery light flashing 8 times

Congratulations 👏

[chipmaster86]

Re: HP Probook 6450b not powering battery light flashing 8 times

I almost thought with no xtor in there. And it was working! But 8 blinkies came back.

[chipmaster86]

Re: HP Probook 6450b not powering battery light flashing 8 times

Darn. Yep, you do need the SOT-23, or a shunt for 19v to center pin. Thanks Guys!