How to replace the multi-function high voltage board?

Usually when the laptop has a high-voltage board failure, or burns the high-voltage bulb on the screen. The machine still boots normally but the screen is black and you have to look closely to see the text. For those who have been repairing laptops for   years with full high-pressure boards, screens, and high-pressure bulbs to test, this pan is very quick to fix. But for those who are new to the profession or those who do not have many laptop bodies to test, the inspection is also very difficult. To properly check the disease and buy the right replaceable parts is essential.

First, when the machine boots but the screen is black, look closely to see the text, you need to check the high pressure ball first. To check if the high voltage board is working or not, you need to do the following steps:

Remove the monitor, unplug the high-voltage bulb connector from the monitor.
Use a separate high-pressure bulb, which can be taken from the broken screen, the screen is striped… And make sure that the ball is in good working order.
Plug the high voltage bulb into the jack of the high voltage board and start the machine up.

There will be 2 cases: The high pressure bulb is bright and not bright. If the high pressure bulb is bright, your screen has been burnt out, just replace the high pressure bulb on the screen. Case 2 is If the high-voltage bulb does not light, your machine will damage the high-voltage board or lose the power supply to the high-voltage board (because the high-voltage bulb to test is still alive). It is important to note that the power supply for the high-voltage bulb is very high from 500 – 1000V  not deadly, but touching it makes you startled and unlucky, it will break the screen, or the client’s computer, so be careful when checking .

When checking that the high-voltage board is damaged, you proceed to replace the high-voltage board. For those of you who have a lot of machines, you just need to get them from another machine to replace them, for those with few or none (like myself), you need to buy a multi-function cable board. The universal high-voltage board can be replaced for almost all models, it has a wide voltage range from 9v -20v. And needs to be measured and soldered.

+ On the multi-function high-voltage board, there are 4 input pins and 2 high-voltage output pins (with a voltage source of several hundred volts).

V-in 5v or 9v-20v. This pin connects to a fuse on the high voltage board, determine this pin by measuring the continuity with the fuse located next to it.
Foot GND foot mass.
High voltage on/off pin, this pin has a voltage of 3v3
The adj pin adjusts the brightness and darkness, this pin has a voltage of 0 – 5V. If you do not solder this pin, the screen will light up at startup and then see the text.

+ The wire connecting to the high voltage board of the zin machine (not yet replaced) usually has 6 wires or 5 strands or more, depending on the machine.

2 red wires are V-in.
2 black wires are GND (ground pin).
The other 2 wires are the green wire connecting the on/off pin (En), the yellow wire connecting the adj pin. Or maybe orange and white.

To be sure, turn on the machine and adjust the meter to the vol scale, the black rod is clamped to the mass, the red rod is attached to the pins on the plug wire and measure each pin with a voltage of 9-20v, it is the V pin. -in, pin 3v3 is on/off. Pin 5v is adj, pin 0v is mass pin. Then proceed to solder to the multifunction board.

+ In case of measuring on the adj and on/off pins, both have 3v3, it is necessary to use the exclusion method. 2 V-in and mass pins are easy to find and solder to the board. The rest of the adj and on/off pins are needed. Use subtraction by connecting a wire to the on/off pin and then starting, the machine still doesn’t light up, it’s the adj pin, and if the light is on, it’s the on/off pin, then hook the rest of the wire on. is to be.

+To accurately pin on/off is also simple when you have the same board and are active (eg your machine is still running, just take it out to try). Determine the on/off pins on the high board. pressure by:

Remove the machine screen with the high-voltage board alive.
Plug the power into the laptop, do not turn it on.
Adjust the chronograph to the X1 ohm scale, the red rod is plugged into the mass, the black rod is plugged into the on/off or adj pin. If any pin that the high-pressure lamp lights up, that pin is the on/off pin.

Use an analog meter to check the on/off pins on the high voltage boardThat’s how to determine whether the high-pressure board, the high-pressure ball is alive or dead. There is also a case of SIO chip failure, male chip or loss of 19v, 3v3 voltage for the board to make the ball not bright (but in the article, I only show how to replace the multi-purpose high-voltage board when the chip and voltage are good). Wishing you success.