acer power controller. What to do if the laptop battery is not charging

Diagnosing a laptop motherboard malfunction is the most important step in repairing it. But to diagnose the board, you need to know the sequence of its inclusion.

Laptop turn on sequence

When the laptop is turned on, the standby voltage is supplied through the button to the multicontroller, which starts all the PWM controllers that generate all the voltages (there are many of them). With a normal outcome, the multicontroller generates a PowerGood signal. This signal removes the reset signal from the processor and it starts executing the program code written in the BIOS with the address ffff 0000.

The BIOS then runs POST (PowerOnSelfTest), which performs system detection and self-test. During the self-test, the video chip is detected and initialized, the backlight turns on, and the processor type is determined. From the BIOS data, its clock frequency, multiplier, settings are determined. Then the type of memory, its volume is determined, it is tested. After that, the connected drives are detected, initialized and checked - a drive, a hard disk, a card reader, a floppy drive, etc., and then additional devices are checked and tested.

After the POST is completed, control is transferred to the operating system loader on the hard disk, which loads its kernel.

We give a diagram of the sequence of turning on the laptop

Laptop motherboard diagnostic algorithm

checking the supply voltages according to the datasheet;
checking PowerGood and start signal;
BIOS polling control;
Postmap loading diagnostics showing at what stage the loading stops.

We are considering 2 options.

Laptop power light not on

1. Power does not appear and also the power LED is off.

We are looking for a malfunction in the power management circuit. We check the Multicontroller - a microcircuit that controls PWM circuits, voltage generation. It also has built-in peripheral controllers. For example, a controller for the keyboard, mouse, temperature, fan, battery, touchpad, etc. Sometimes a USB controller is included in the multicontroller. Often this is an ITE chip.

The multicontroller is powered directly from the adapter (usually 19V). And then the voltage is transmitted to other devices. Thus, the controller controls the power-on process in the laptop.

The power switching circuit may also be responsible for power distribution, for example, there may be a MAXIM chip. It is responsible for switching power from an external adapter to battery power, controls charging, etc.

In some cases . In this case, the laptop does not start, although all voltages are present and the necessary signals are given.

The power light is on, but the laptop does not turn on

2. There is power, the power LED is on, but the laptop does not turn on, the screen is dark. The hard drive LED first turns on and off, then turns off.

The troubleshooting algorithm on the motherboard is as follows.

We disassemble the laptop, warm up the chipset chips in turn. After each warm-up, we try to turn it on. If the laptop turns on, then a specific chip is to blame.

It is also useful to know how the breakdown occurred. For example, the history of the breakdown is very important. If the USB ports stopped working before the breakdown, then the South Bridge most likely failed. But with artifacts on the embedded video, the North Bridge is to blame.

Methods for diagnosing the motherboard

You can read about methods for diagnosing a laptop motherboard. It describes how to determine a faulty chip, search for a short circuit on the board.

Main ways:

visual inspection
study of the history of failure
using a diagnostic card
chip warming up
limiting the supply current when searching for a short circuit, searching for hot elements

Let's not spend a lot of words to say how important and how much a modern person needs a laptop. Not a single day goes by without it. For work, personal communication, creativity, reading, study - a laptop is a universal assistant. Replacing the Dell laptop charge controller is one of the most serious breakdowns. The difficulty lies in the fact that this chip is located on the motherboard. It is very difficult to unsolder it carefully without hitting nearby elements. This requires specialized equipment - an infrared soldering station, which is equipped with Service Center No. 1. Let's take a look at the topics below:

Reasons for failure;
replacement process;
Guarantees.

Causes of failure

How do I know if my Dell laptop needs a charge controller replacement? Let's start with the fact that the mentioned microcircuit controls the current supply to all parts and compensates for the difference in energy flows in the network, is responsible for the process of charging and discharging the battery. A sudden power outage, power outages first of all hit the controller. It is within his competence to regulate the temperature and pressure in the laptop with the help of a temperature sensor so that it does not overheat, does not freeze in the cold, to prevent gas leakage and explosions.

If the device does not see the battery, but it is charging, or if it does not turn on for a long time, it lights up for a few seconds, and then turns off again - these are signals that the Dell laptop charge controller needs to be replaced. Another symptom is that if the device gets very hot and turns off by itself, it is not possible to charge the battery - the charge level does not increase, regardless of the charging time.

Replacement process

The failure of the controller actually means that the block of rechargeable cells (the battery itself) needs to be changed. And in some cases - if the power board or another microcircuit has also burned out, you will have to change the motherboard. There are cases when a laptop works with faulty components for a long time, then there comes a “point of no return” for the device, i.e. it breaks completely and can no longer be restored. In order not to bring the laptop to such a state, it is recommended to apply for a replacement of a burned-out element as soon as possible.

The replacement of the controller itself is carried out as follows. First, the Service Center engineer disassembles the laptop. He treats the part with a flux (a gel that removes an oxide film and helps the liquid solder to work), sets up an IR soldering station and substitutes a motherboard with a burned-out component under it. After waiting for the required exposure time, he dismantles it and similarly solders a new serviceable spare part. After the master removes the remnants of solder and collects the laptop.

Guarantees

To prevent the correct operation of the device, the Service Center recommends charging the battery only after it is completely discharged and using a power supply that restrains power surges in the network, which prevents damage from them. After replacing a Dell laptop charge controller, an engineer must test the design without fail. And only after making sure that the device works smoothly, it is returned to the user. SC issues a guarantee of up to 3 years for this type of repair, provides free diagnostics and door-to-door delivery.

Repairing Compal motherboards with a “does not charge” or “does not turn on” malfunction, especially after flooding with liquid, often causes difficulties for craftsmen. Consider a typical power supply and charge circuit used in Acer laptops, using the LA-6552p platform as an example. This motherboard is installed in Acer 5552 and Emashines E442 laptops. Other motherboards that have an ISL 6251 charger chip in their composition are built on a similar principle and have minimal differences.

We will consider in parallel the typical circuit for switching on the ISL6251a charger and those parts of the laptop circuit that are associated with starting and charging the battery.

ISL6251 charger operation and battery charge.

+ 19V power is supplied to the 24th pin of the DCIN charger chip from the power connector through the PD16 diode and the PR281 resistor. If you replaced the chip, check if the resistor is intact. Inside the microcircuit, at pin 1 VDD, a supply voltage of + 5V is formed, which is then fed through PR86 to pin 15 of the VDDP and powers the rest of the microcircuit. We check the presence of + 5v at pin 15.

The VREF pin should have a reference voltage of 2.39v generated by the charger

The ACSET input - the charger detects the 19V supply voltage, which the divider on PR280 and PR282 lowers by 14 times. To do this, the voltage on ACSET must exceed 1.26V, which corresponds to 18.0V at the input. Having detected normal power, the charger lowers ACPRN to a low level - it sends a signal to the multicontroller.

The multicontroller communicates with the battery controller and, if charging is necessary, sets a high level at the EN output of the charger, allowing it to charge.

At the CELLS pin, the multicontroller sets a voltage depending on the number of cells in the battery, thereby indicating to the charger what voltage to apply to the battery.

The CSIN CSIP pins are connected to the power supply current sensor - resistor PR61, and the CSON CSOP pins are connected to the charge current source. When the current is exceeded, the charger turns off the battery charging.

Thus, in order to charge the battery, it is necessary that the charger be powered (DCIN = 19v, VDD and VDDP = 5v, VREF = 2.39v), so that it detects power (ACSET> 1.26v) and the multicontroller gives it an EN signal.

Generation should start on transistors PQ55 PQ57, currents on PR61 and PR78 should not exceed the maximum allowable. It should be noted here that in addition to the resistors PR61 PR78 themselves, PR74 PR76 PR72 PR73 can also burn out, because of which the charger may measure currents incorrectly.

Operation of LA6552p power circuits. Initial start-up and appearance of stresses.

For the laptop to work, it is necessary that the input field-effect transistors PQ14 PQ15 open. They are opened by the PQ68B transistor. It also opens the high level of the PACIN signal. Blocking is assembled on transistors PQ68A, PQ21, PQ19 - a low level at the PQ68A gate leads to reliable closing of PQ14, PQ15. It can also happen if the multicontroller raises the ACOFF signal.

Now let's see where PACIN comes from. According to the diagram, we see that from 6251VDD through the PR286 resistor. In addition to this, PQ67 must be closed, for which the charger must detect the presence of external power (ACSET pin) and lower the ACPRN signal.

By the way, ACSET is not formed from the VIN voltage from the connector, but from the PreCHG voltage, which, in turn, is already formed from VIN by four resistors PR124-PR127, so if the latter are open, the charger will not see the connected adapter.

Start PWM RT8205, standby voltages +3 and +5

On this platform, standby voltages are generated only when powered by an adapter.

Consider the operation of a laptop without a battery, since when repairing the motherboard, the master usually does just that, powering the board from a laboratory power supply. After connecting the adapter, VIN and PreCHG appear. Through the PR128 resistor, it enters the base of PQ34, opening it, and he, in turn, opens PQ31, applying PreCHG to B +. Since no nodes are running yet, there is no consumption on B+, the capacitors connected to B+ are charged through resistors PR124-PR127

When the B+ voltage reaches enough to start the RT8205, the +3VLP and VL voltages appear. And then, if the launch is not blocked by transistors PQ63A, PQ63B, voltages + 3ALWP and + 5ALWP In order for the launch to occur, PQ64 must be open. For this to work, VS must be present and ACPRN must be low. VS is taken from VIN through resistors PR10 PR11.

When on battery power, VS is absent and appears when you press the power button. Thus, when powered by battery in standby mode, the RT8205 generates only +3VLP and VL.

Many Compal platforms have similar schemas. Some may use op-amps to generate ACSET and other signals. These nodes can use the 3V RTC voltage to generate the reference voltage, such boards do not start if the clock battery is discharged.

Replacement of the Acer tablet charge controller is carried out under conditions that guarantee the correct operation of the device. Tablets replace a lot of things for a modern person - they record a variety of necessary information - from a daily schedule to PIN codes and passwords. Therefore, the urgent tablet repair service is popular. The cost of work and the timing of the repair operation are determined on the day of visiting the Service Center. Parts replacement steps:

Acer tablet diagnostics;
Disassembly;
replacement process;
Guarantees.

Acer tablet diagnostics

The charge controller is a microcircuit that is integrated into the motherboard. It is responsible for the charge and discharge cycles of the device. In fact, it determines the life of the battery and the amount of energy that it can take. The spare part requires careful handling.

A problem with the power chip is less common than a failure of the battery or power connector. Therefore, to determine the exact cause of the breakdown, the Acer tablet is diagnosed. This procedure indicates the condition of the hardware and determines the presence of hidden defects.

Failures in the "power supply" are fraught with battery failure. The battery is designed for a limited number of full discharge / charge cycles, after which the ability to accumulate energy gradually dries up. The controller, in case of incorrect operation, knocks down the battery settings and disables the device.

Disassembly

Since the charge controller is integrated into the motherboard, to replace the charge controller on an Acer tablet, you need to open access to the module. To do this, the engineer removes the back cover of the tablet, removes the battery and dismantles the mounting bolts and the case. He then removed the modules adjacent to the chassis. In some Acer models, the motherboard is directly accessible, while in others it is necessary to conduct a deeper analysis.

Replacement process

Manipulation is realized by soldering elements. Due to the small size of the component and the proximity of the integrated elements on the motherboard, the engineer must have "surgical precision". An infrared soldering station helps him with this - it automates the soldering process, eliminating errors. The old, failed, controller is soldered, and then (subject to the specific temperature conditions of the surrounding modules) a new one is soldered, which fits the model of the tablet computer being repaired.

Guarantees

Replacing an Acer tablet's charge controller is a delicate operation that requires specific equipment and engineer experience to be successful. The service center works only with original parts suitable for this tablet model. Therefore, a long warranty period is provided - up to 3 years. After the repair, a test inclusion of the Acer tablet is implemented in the presence of the user.