Laptop won't power up with AC adapter and won't charge battery

[pepi93]

1) the laptop doesn't power on without a battery
2) the light which would indicate that the laptop is plugged into the ac adapter is not on when the ac adapter is plugged in.
3) the battery charge light is also not on, which would indicate the battery is being charged.

The battery does not charge...
The AC adapter is fine, tested with other laptop.
The battery is also new and works fine

I took the laptop apart. Took out the DC Jack and tested it separately.

I used a crappy non digital volt meter. Set it to 50 DC V. Plugged the DC Jack into the AC adapter...

There are 2 red 2 black. Each red shows 8V exactly.

I plugged the dc jack into the motherboard with the AC adapter connected, with the motherboard out and proceeded to test the various contact points on the 4 pin connector with the dc jack plugged in. I tested contact points on both sides of the motherboard on the soldering points. Each time getting the 8V reading.

Thanks for the help

 

[jarotech]

To confirm that the U6000 is not defective, on the capacitor C6028 you will read zero volt on both side. The voltage should be 1.68V on one side to detect the adapter.

 

[pepi93]

Just tested the c6028....its as you say, 1.68v on one side and 0 on the other side.

You think maybe there was a surge in the circuitry and by removing all the parts and doing this testing I may have fixed this? You remember in our initial testing I said I got some sparks? This is no longer happening, I've touched those same components again near the U6000 and there are no more sparks.

 

[jarotech]

Ok, the adapter is detected but the MAXIM (U6000) is not giving the voltage to switch on the MOSFET Q6002. So, check the MOSFET Q6004 on the 3 pins.

 

[pepi93]

only one of the 3 pins shows a voltage (17v) to be exact...it's the 2nd pin on the side where there are two which shows the voltage...the other two pins show no voltage reading.

 

[jarotech]

Can you give me all the voltages on the chip U6000. Here is a picture of the pinout.

 

[pepi93]

1 - 0v
2 - 0v
3 - 19v
4 - 5.8v
5 - 0v
6 - 0v
7 - 8v
8- 3.2v
9 - 3v
10 - 3.8v
11 - 3v
12 - 3v
13 - 3v
14 - 0v
15 - 3v
16 - 3v
17 - 0v
18 - 0v
19 - 1.5v
20 - 3.9v
21 - 4.4v
22 - 5.8v
23 - 0v
24 - 0v

again all my measurements are with a crappy non digital volt meter

 

[jarotech]

From all the readings you did, the problem could be the charging chip U6000. I'm not certain at 100%, but one reading said that the chip is defective. I could be wrong, but this is what I conclude.

 

[pepi93]

based on my original symptom it is the charging chip...which part of the U6000 is the culprit? Thanks for all your assistance, I enjoyed learning a bit.

 

[jarotech]

You have the pin 3 named DCIN, this pin is the Charger Supply Input, on this input you read 19v, the voltage from the adapter. After you have pin 19 named ACIN, it's the AC Adapter-Detect input with 1.5V, it's compared to a fixed voltage of 1.485V (typ). The two readings are good, but the comparator inside the chip gives a low signal to the ACOK who is the AC Detect Output. The pin 10 is the ACOK, it should be low when the AC adapter is present and enables the charger. But you have 3.8V on pin 10, also you have the pin 14 named PDSL, who at the presence of the adapter should give 8V above the voltage of the adapter, but you have 0V. You have some voltages from this chip who are not good to use the adapter for the main source of power.
Sorry if it's too technical.

 

[pepi93]

no this is perfect, thank you.