Lenovo Z50-70 ACLUA/ACLUB NM-A273 Dead Board: Voltage Issues, PD304 Diode, PQ301 Replacement

Lenovo Z50-70 ACLUA / ACLUB NM-A273
Laptop drove up dead. The voltage on the center pin of the 1.3V power socket. The voltage jumps 0.20V-1.29V behind the PD304 diode. Damaged PQ301, after replacing 4407A, the board started responding to the switch. So after pressing power, the diode lights up, after plugging in the battery, the charging diode flashes. The battery is charged with the voltage of about 14.8V, after removing the battery it is 1.9V. Unfortunately, only that much, the fan does not move, the image is missing etc. PQ302 4n -5.2V, the rest 1,2,3,5,6,7,8-20V. Voltage on UC3 (BIOS) -3.3V.
The voltages appear on only three coils, PL302-1.9V PL304-5.1V PL303-3.3V. At rest it is 0V.
The converter BQ737 substituted with BQ727 I had - no changes.
What voltage should be behind the PD304 diode? . I will be grateful for any help.

Hello.
Enter the current consumption of the board with and without batteries before and after pressing Power.
Did you check the BIOS?
Do you have a schematic for this album?
best regards

The subject of this Link will help you find MS and explain some things.
* there are only 9 topics about this MB

janko23 wrote:

What voltage should be behind the PD304 diode?

- depends on the power of the power supply - it identifies the power of the power supply. If the board starts and the battery is charging - the voltage is correct.
Also, do not look for a problem with the charger chip. Check that you do not have low resistance on the converter coils - in particular the CPU power supply and integrated graphics.

Bios pre-programmed, no schematic.
The PL705 on the coil is only 13 Ohm. What voltage should be behind the PD304 diode? Thanks for the help in advance. best regards

Is PU 401 there, do you have + 3VLP or + 3VL?

I cannot locate PU401

Well, you have 3V / 5V converters on two SY8206BQNC systems.

If it doesn't help anymore?
Remember that (PQ302) P-ch and with him N-ch (PQ301)




BQ should give a signal for PQ990B> this one should open PQ307B ...> this one opens PQ301 and PQ302.
See what about the BQ24737_VDD?
ACOK signal active.
In the datasheet it is described as #, which is if 0? that's ok.

ps
These PD304 or AZ-5425-01f
* identical in Compal_nm-a181, only numbering of transistors PQ312a / PQ312b



No LED> from this forum Link_ problem
Availability Link_ about PLN 29 and datasheet in app.

The diagram is not exactly like this board, but similar.

The 4th time is with


System PU904 (SY8206BQ) / PU905 (SY8208CQ QFN-10) i.e. 3.3V / 5V

Both circuits produce a voltage of 3.3V and 5V. At the moment I have 0V behind the PD304 diode. Can I try to give these 1.4V from the middle pin of the socket?

janko23 wrote:

Can I try to give these 1.4V from the middle pin of the socket

- no. Unless you want to introduce another bug.

Check the basics - voltage on:
ADAPTER_ID_ON # - for n. 84 NCBs.
on all PQ995 feet
BQ - voltage on n. 5

PR336 - in case of problems with identifying the power supply, you can temporarily solder it.

Measurement without batteries, only power supply - original, functional, with adequate power or service power supply with a properly prepared plug.

Enter the hob's current draw before pressing the switch and after pressing it.

You can give about 1.2V per pin from an external power supply. ADAPTER_ID / power supply on the board / + of course + 19V
Should take off

Check this 3V regulator there are two such 3V and 5V.
On the 3V system, you should have + 3VLP or + 3VL and check the resistances on this pin.
There is pin 5 of the LDO on the system, i.e. +3 VLP.
If there is no LDO there is a problem.
You didn't need to replace the Charger chip.
If you want to get help, answer the questions.
Provide voltage from the regulator 3 V from 1 pin to 6 pin?
Lenovo
65 W, 20 V power supply:
285 ohms from ID to GND.
90 W, 20 V power supply:
548 ohms from ID to GND.

adamadi33 wrote:

Check this 3V regulator there are two such 3V and 5V etc.

Yet:

janko23 wrote:

PL304-5.1V PL303-3.3V

lisek wrote:

You can give about 1.2V per pin from an external power supply. ADAPTER_ID

- for what?
If there is no this voltage and there is EC_ON as evidenced by + 3VALW, then either the resistance in this circuit is low, or the KBC does not work properly, or the PQ995 or small items are damaged (assuming that the power supply, power supply socket is OK).

You can

sk1977 wrote:

PR336 - in case of problems with identifying the power supply, you can temporarily solder it.

- which will omit PQ995 and give a starting point for further actions.

The author has not yet provided basic information with which to start - e.g. if the current consumed by the board is around 20mA - the KBC is damaged in 99% and there is no point in looking for other reasons.

There at the damage. PD304. (Then this diode, as a damaged one, is a resistor of approx. 5/70 ohm in both sides, this can be measured after hitting the circuit) usually it falls on KBC (there is a small hole in the housing).
* Measure the whole track from pin to kbc, will you eliminate other broken pieces?

Hello, unfortunately after replacing the NCB (programmed). Bios rewritten. After switching on, the power LED went on, the battery LED blinked 5 times, both went out and then turned on again blinking from the battery 5 times. After a few such runs, both went out, and unfortunately the power does not light up anymore.
The resistances of the keys without power supply with RAM, relative to mass. Other measurements of the battery contacts 1.9V, bios 3.3V, power 3.3V, rtc- 2.8V, short to ground behind the PD304 diode. Resistance from the middle pin to the pin behind PD304- 827 Ohm.

PL307 -278Ohm
PL701 - 152Ohm
PL302 - 0.35MOhm (result after 30sec of measurement)
PL705 - 12 Ohm
PL706 - 12 Ohm
PL9 - 253 Ohm
PL304 - 75 kOhm (as PL302)
PL303 - 368 Ohm
PL302 -0.35 MOhm (result after 30 seconds of measurement)

NCBs:
21-0.02V
26-3.34V
72-1.43V
86-3.34V
93-3.34V
111-3.34V
124-0V
128-3.34V

The voltage from the pd304 diode goes to the n72 KBC, through the PR322 resistor, unfortunately I can't locate it.


The problem was PQ301, KBC, BIOS. At the end, I messed up a bit myself, rearranging the general cargo to KBC. Thank you for your help. best regards