Toshiba L650-1MM not power on always (Main 6050A2332301-MB-A02)

Hello friends of the forum, this laptop has the following defect: if I connect the power supply, the LEDs of the connected power supply flash for a moment but then it does not start. Trying several times to connect it, the led becomes fixed and then the machine starts quietly. I didn't find any traces of oxide. I tried to replace U6000 but same defect, reprogrammed the eeprom of the bios and kbc but same defect. I noticed that when it does not turn on, the voltage of 3.3v and 5V on the L6200 and L6201 coils is not present. Meanwhile, I detected these voltages on U6000 and U5200:

U6000:
PIN 1 0V
PIN 2 0V
PIN 3 19V
PIN 4 5,44V
PIN 5 0V
PIN 6 0,3V
PIN 7 5,3V
PIN 8 0V
PIN 9 0V
PIN 10 0V
PIN 11 0V
PIN 12 0V
PIN 13 0V
PIN 14 19,46V
PIN 15 19,46V
PIN 16 19,46V
PIN 17 0V
PIN 18 0V
PIN 19 1,70V
PIN 20 5,4V
PIN 21 4,09V
PIN 22 5,4V
PIN 23 0V
PIN 24 0V

U5200:
PIN 1 OV
PIN 2 0V
PIN 3 2V
PIN 4 3,34V
PIN 5 0V
PIN 6 1,28V
PIN 7 0V
PIN 8 3,34V
PIN 9 4,57V
PIN 10 0V
PIN 11 0V
PIN 12 0V
PIN 13 1,20V
PIN 14 2V
PIN 15 0V
PIN 16 19,46V
PIN 17 5,04V
PIN 18 0V
PIN 19 0V
PIN 20 0V
PIN 21 0V
PIN 22 4,57V
PIN 23 0V
PIN 24 0V

Hello!

You probably mean the chip U6200, not U5200.

Measure the voltages to ground on pins 44, 67, 68, 69, 70, 82, 95, 102 of KBC chip, when the machine does not turn on.

You probably mean the chip U6200, not U5200.

Sorry Matic U6200 exact
kbc :
pin 44 0v
pin 67 0v
pin 82 0v
pin 92 0v
pin 102 0v

Open the jumper PAD6201 and check, if the voltage on coil L6201 will appear.

[quote]Open the jumper PAD6201 and check, if the voltage on coil L6201 will appear./quote]
Yes appear.
Matic I noticed something, if I heat u6200 the led lights up perfectly, if I cool it it gives me the usual problem, it makes me think that it is defective u5200, what do you say?

Check the solder joints on all pins of U6200.
If they are good, replace U6200.

The joints are ok. I replaced U6200 and it seems to work perfectly. I keep it in test and let you know the result.

Matic, I'll update you on this laptop.
Kept it on trial, the first day everything was ok.
On the second day, however, the DC LED off, as usual I heat the U6200 zone, it starts up again, the LED lights up. I decide to replace the capacitors C6200 and C6202. I also noticed that if I slightly bend the main board, the led goes out so I think of a faulty soldering or a break in the printed circuit. I started to redo all the soldering in the components of the u5200 area and it seems that the led problem has been solved, when I slightly flex the board the led does not turn off anymore. But now I have another problem, when I give the power one the main board does not start. On the connector of the button I find the 3.3v and if I press the power on they go down to 0V but it does not react

Measure the voltages on all coils .

all coil 0V except L6201 3,38v AND L6200 5,14v

Measure the voltages on all pins of U6302.
Measure the resistance to ground of L6300.

u6302:
pin 1 0v
pin 2 0v
pin 3 0v
pin 4 0v
pin 5 0v
pin 6 0v
pin 7 5,14v
pin 8 0v
pin 9 0v
pin 10 4,90v

Resistance L6300 2,3Kohm

Power on measurements.
Measure the voltages on pins 14, 15, 19, 20, 25, 44, 95, 104, 106 of KBC.
Measure the voltages on pin 64 of the KBC in the following cases:
at power off
with pressed power on
to power on.

KBC:
PIN 14 0V
PIN 15 3,38V
PIN 19 3,38V
PIN 20 0V
PIN 25 0V
PIN 44 1,80
PIN 95 0,25V
PIN 104 3,38V
PIN 106 0V
PIN 64 3,38V drop to 0v when press power button and come back to 3,38 after release power button

Replace the bios and remember to save the old one.
If it does not resolve with the new bios replace the KBC.