t43p don't charge battery

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AdaSch · #1 Post by **AdaSch** » Sat Dec 13, 2008 12:57 pm

Hi,

some time ago i blow f3 fuse after connect sxga lcd from dell. After replace f3 system work but...

my battery won't charge. i check second battery, still don't charge, ultra bay battery too don't charge,

i check all fuses on board - all ok, i look too on IC, everything looks good.

my ThinkPad see dock and power from dock, -still don't charge, this same on regular power supply. after connect power my system recognize this, increase lcd brightness, battery led go to orange, info in battery maximizer is change from discharge to charge. in charge mode electric stream is 0.00 A and battery energy level is this same. In discharge mode i can see how many power use system, and I can see value electric stream

anybody can help? some one knows which one IC is battery controller/charger? how i can check this? (i am electronic engineer, i have testers, knowledge, tools for repair etc.)

THX

SMA · #2 Post by **SMA** » Sat Dec 13, 2008 3:07 pm

Yeah, that was a quick win with that F3 fuse. Just too bad that we did not catch all problems.

But having an electronic engineer in the other end, then it should be possible that we can nail down this one too.
There are others having reported similar problems on this forum lately. So let's go to work.

First, I will have to ask you NOT to go into replacing chips randomly. That is, with no reason. Others are trying that.
In my opinion, that will only add to the number of variables to take into consideration.
The right procedure is to measure voltages.

The chip responsible for battery charging is an ADP3806 on the top side of the board. I do not believe that this is the one holding the error, but one will have to start by looking at that one.
Download the datasheet so that we will be on the same page. Then, with the ThinkPad having the battery indicator gloving Orange, measure the DC voltage
on pin number 24 and pin number 10 of this chip.

In a T43 things might be slightly different. I am going by a T41.

I do have some more to add, but that is not going to be today. I will do my best to stand by.

#3 Post by **richk** » Sat Dec 13, 2008 4:25 pm

If it will run off the battery but won't charge, there is a little fuse to check. On the bottom of the board by the docking station connector next to the battery terminals. There is a large fues for running off the battery and very near there, there is a little black fuse with an "F" on it that is for the charging current.

SMA · #4 Post by **SMA** » Sun Dec 14, 2008 1:01 am

It is correct that there are 2 fuses for each battery connector, but it is not correct to say that the large fuse is for running off the battery.
The large fuse is for the charge and discharge current.
The little black fuse is there to provide power and/or sense voltage to the circuitry that has to open the mosfet's so that current can
flow in the direction needed by the operation in progress (charge, discharge or nothing).

But anyway, it is not likely that this machine has problems with these fuses, since the problem goes with both battery connectors.

SMA · #5 Post by **SMA** » Sun Dec 14, 2008 9:32 am

As I have said earlier, I do have a little more information. Here it is link

AdaSch · #6 Post by **AdaSch** » Sun Dec 14, 2008 11:54 am

SMA wrote:As I have said earlier, I do have a little more information. Here it is link

WOW!,

thx, now i can check where i loose power or maybe stering signal is wrong

after shortcut second from left TPC8014 charge starts

thanks, but problem is - no steering signal on G LEG

do you know what steering this?

cheers

SMA · #7 Post by **SMA** » Sun Dec 14, 2008 12:59 pm

I realize now, that I should have assigned some numbers or names to those mosfet's. To make it easier to refer to them.
But if I am not misunderstanding it, then the mosfet that you have been shorting is actually supposed to be closed.
Shorting that one will provide a direct current flow from the DC-IN to the battery pole. Not a good thing for the battery to be charged at 16V. You may have harmed your battery already by doing so.

Shorting mosfet's is not a good idea. Measuring voltages is much safer. That said, of course you can do what you like, it is your ThinkPad.

In trying to understand these mosfet's it might help to think of them as switches or relays. They will be either on or off.

Note that the 'System DC' is supplying power to run the ThinkPad.

Except for a few, I do not know where all the Gate signals are coming from, but I will expect them to be derived from signals coming from the TB62501F chip, which can be found at the top side of the board, below the mPCI card.

AdaSch · #8 Post by **AdaSch** » Sun Dec 14, 2008 5:29 pm

Hi,

i found 2 errors

1. first leg (vcc) ADP3806 is connected by 10ohm 0402 resistor do main power (16v) my resistor don't have 10ohm but many kohm (i think, is burned after overload)

2 after replace resistor charge still don't work because 23 leg don't give good signal (is 1,4v; should be near 15v) to mosfet gate. After short 24 and 23 legs (battery voltage and mosfet gate) charge is starting. Tomorrow i try replace adp3806.

digram be very useful but i lost many time when search why on 1 leg is only 12v. diagram don't have 10ohm resistor. i found him on typical application (from analog website)

V large thanks!

p.s.
when replace adp i give info on forum

edit

hi,

i relace resistor, adp3806 and mosfet after adp. now all work

thx

supersebas · #9 Post by **supersebas** » Sat Feb 28, 2009 1:57 pm

Hi... just a question, after you replace f3, the system boot up with the new sxga screen?
I'm asking you because i have the same problem, when trying to exchange the xga to sxga f3 blew up.

AdaSch · #10 Post by **AdaSch** » Sat Feb 28, 2009 6:45 pm

yes, system start without problems.

t43p don't charge battery

t43p don't charge battery

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