Dead Lenovo Thinkpad Edge E520 (BIOS ?)

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

Thanks for trying to help, but I'm a newbie, so I need some extra guidance here.
I'm not familiar, with the internals of a laptop.
Where should I start measuring? I have just jumped on the BD9528, but maybe I was wrong, in stating my repair at this IC.
The weird problem I'm having, with this IC is that sometimes I'm getting 2.2V at the two separate battery terminals and then later, it drops to 0.3V. I can't explain it, what is going on here.
This BD IC, seems to be the main power supply, for 5V and 3.3V sources, right?
I can't seem, to get any 3.3V source out of it. It could be already damaged? I have just replaced it.
So, right now the BD9528 and the EEPROM(U601) ICs, are replaced.
I don't have a E520 schematic, the only thing I have found, like the op, I have the E420. I'm not sure, how similar are they though.
BD9528 is on page #41.
Green LED, next to the power plug, does not light up, when the plug is plugged in.

[khaahk]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

Is the exploded tape on the other side of the 9528 which you say you changed? If you left tape there and used hot air, then any components beneath might be lifted off with the tape. Look under the tape!
BD9528 should output first 3.3V on pin 28 and 5V on pin 29. Also it should have adapter voltage on pin 30. Check these things.
If they are present then need to check if EC gets power and power button has voltage.
EC gives the BD9528 command to enable outputs on pin 1 and 24.

[fddizon]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

tibimakai,

sometimes we loose our senses and we forgot who we really are. lol
wake up veteran!

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

I'm not veteran here, only in the TV section.
At pin #30 the 20V is there, at #29 there is 4.75V(seems to low), but there is nothing at pin #28.
There is no voltage at the start button.
After replacing the BD, I had these voltages, then next day they were gone.
I have a feeling, that the BD is gone again.
When I have used the hot air, there were no black tape. I'm using kapton tape around the BD and BIOS chip. But, you may be right, about the other side, I did not think about that, I will check, when I get home.
It took a lot of time, to lift that IC from the board(has heat pad).

[fddizon]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

check vin if present, check pl4101 and pl4102 if voltage present

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

No parts under the tape.

[khaahk]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

3.3V must be present at #28, either short on that rail or BD faulty or bad connection.

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

I will look into that.

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

I'm taking a brake with this, since this month I'm moving.

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

I ended up buying another board from Ebay which suppose to work, seller shows pictures with BIOS.
I ended up (most likely)messing up the connector at the LCD, while I was plugging in.
Behind, the most two right pins, the plastic backing broke off and the pins most likely, touched the connector's housing, or each other.
Now the motherboard starts up, the green LED turns on, by the power plug, the fan spins up for a couple of seconds, HDD spins up and worms up, DVD shows some life as well, but I can't get any picture on the display, nor on an external monitor.
What did I screw up?
I have checked a couple of fuses, but they all show a good value. F4902 shows a value of 1.0 Ohm, which seems slightly higher, then it should be.(page #49, LVDS connector)

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

Anybody could help, with this second motherboard fault(that I have caused)?

[atsio]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

Post the volt reading on every pin of the lvds connector.

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

I will do that, when I get home.
It is a 40 pin connector, and I believe that with the last two I had problems(#39 and #40). #40, I believe is not connected(NC).

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

Should I measure, with the LCD connected, or just the empty connector, with laptop turned on?
Right now, the laptop(mobo) turns on and the fan spins really fast for a couple of seconds, then stops spinning and then, spins up again really fast, until I stop it.

[atsio]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

Probably the board reboots repeatedly. Do you have a lab supply? If not, cut the wire of the laptop power supply and check the amps drawn when you start the board with a multimeter. Is the board exactly the same as the one is replacing?
It is better to check voltages on lvds connector while the screen cable is connected because some boards will not start to send signals to lvds if there is no screen. Of course you read the values after you press power button.

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

I have a lab supply. I will use that, to power it and get the amps used.
It is the same exact board. The other one, I believe had some power (IC)5V/3.3V issues. I have replaced that IC, but it did not fix the problem.
Like it's getting worse every time I have a go at it. Now the Vin is fluctuating and never gets to 20V, at that IC(5V/3.3V).

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

OK, here they are:
#1: 20.318V
#2: 20.318V
#3: 20.318V
#4: 0V
#5: 0V
#6: 0V
#7: 3.332V
#8: 3.337V
#9: 0.0026V
#10V: 0.0025V
#11: 0V
#12: 0V
#13: 0.408V and then keeps dropping
#14: 0V
#15: 0V
#16: 3.2924V
#17: 3.2924V
#18: 3.3367V
#19: 0.0029V
#20: 0V
#21: 0V
#22: 0V
#23: 0V
#24: 0V
#25: 0V
#26: 0V
#27: 0V
#28: 0V
#29: 0V
#30: 0V
#31: 0V
#32: 0V
#33: 0V
#34: 3.375V
#35: 3.375V
#36: 3.380V
#37: 3.380V
#38: 0V
#39: 0V
#40: 0V

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

I'm checking the other board and the four FETs at the BD95280MUV look suspicious, at least two show short and the other two show different reading then on the other board.
I would need some help, finding these FET transistors: S406 and PBNDT(seems like it is a Fairchild= F mark). I can't find anything. Size is 3mm x3mm(QFN8?).

[khaahk]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

#38 & #39 should ve 3.3V
Check fuse F4902
then U4901
pin 1 as enable signal
pin 3 as output of 3.3V

[tibimakai]

Re: Dead Lenovo Thinkpad Edge E520 (BIOS ?)

F4902 is good