How to measure a motherboard chip with a multimeter There are so many needle angles on the chip

If you test the power supply, it is generally two pins on the edge of the groove, but it will be short-circuited if you are not careful, generally about 5V; If you want to measure the resistance, you need to know the internal pin diagram of the chip, and it is best not to use this brain if you are not professional.

The file that is used to measure the on/off with a multimeter is the one with the diode symbol painted on it. When it is difficult to measure the foot when measuring the chip, it is good to measure the foot of the part directly connected to the foot and the measured point.

The electrical diagram with integrated circuits should be designed to indicate the voltage value of several detection points of the integrated circuit under normal operation, and at least the working voltage value of the foot directly connected to the power supply, which is commonly represented by VC or VCC. When overhauling the circuit, in the case of judging that the peripheral circuit is fine, measure whether the voltage value of the pins marked by the integrated circuit is normal, you can preliminarily judge whether the integrated circuit is damaged, if the design drawing is not indicated, check the integrated circuit manual or the product description of the integrated circuit or refer to other standard circuits.

This voltage value is relative to the potential difference of the "ground" potential on the circuit diagram, when measuring you put the multimeter in the voltage gear, the black table pen is connected to the "ground" of the design drawing, click on the red pen to measure whether the voltage of that part is normal, if the drawing indicates that the point is negative voltage, you will exchange the meter pen.

The multimeter pen should use that kind of small meter pen, pay special attention not to cause a short circuit, and do not directly point its pins, it always has to connect parts and leads, away from the pins, to avoid causing short circuits.

Some circuit boards are electrified, such as the motherboard of color TV, you should pay attention to the hand not to touch, if possible, use an isolation transformer.

It is best to buy a small crocodile clip, which can be inserted directly into the crocodile clip, which is specially made for instruments. During the inspection, the crocodile clip is clamped on the ground line of the drawing, or you can weld a line yourself, so that you can concentrate on observing the red watch pen and instrument, which is what the factory does for product debugging.

The universal meter cannot measure the mass of the chip.

The quality of the integrated circuit test chip:

Check the power supply: Measure the VCC and GND levels directly with a multimeter to meet the requirements. If the VCC deviates too much from 5V or more, check the output of the 7805 or other regulator and filter circuits.

Check the crystal oscillator: You can change the number of crystals to try again.

Check the reset pin level logic and note whether the model used is a high or low reset.

If the program is designed to run from an extended external ROM, check the EA pins.

If it is determined that the above points are correct, it is reasonable to say that the hardware should function properly.

Then basically determine the problem of the control program, repeatedly trace the debugger in keil, and pay attention to whether the working register group, accumulator, dptr, etc. are expected after the subroutine is called.

The knob selects a larger range than the estimated value, and the watch pen is connected to both ends of the power supply or battery to keep the contact stable.

The value can be read directly from the display, either quietly or upward, if it is displayed as "1.".", it means that the range is too small, so it is necessary to increase the range and then measure.

If a "-" appears to the left of the value, it means that the polarity of the pen is opposite to the polarity of the actual power supply, and the red pen is connected to the negative pole.

To measure the voltage, we first need to prepare a multimeter, and then adjust the multimeter to zero, so that the error can be reduced to the smallest shortage, and then adjust the multimeter to the DC voltage level to indicate that the DC voltage is measured.

Some voltmeters may have to choose a range, and the voltage of the graphics card is generally around 1V, so choose a smaller range.

A multimeter method for measuring a chip.

Measure the resistance, and compare it with a good circuit board.

Almost all electronic components, if it is a wire, can be checked to see if it can be energized. So it's very figurative to call it a "multimeter".

Hello landlord! ~bai

The motherboard of the computer is du can be measured if you judge the master.

If there is a problem with the board, then I don't know that there is a problem, and you can measure it through a multimeter However, you must know in advance the original volts of the components on the motherboard, and then you can know which component is broken, and the motherboard may be able to operate normally after replacing It may be able to operate normally I hope it will help you! ~

I don't seem to have seen a universal meter to measure the computer is a precision object, there is no way to measure this, the power supply can be measured.

Motherboard maintenance and overhaul methods and IC quality judgment methods.

1. Check the board method: 1. Observation method: whether there is burning, burning, blistering, broken line on the board surface, and rust of the socket.

2. Gauge method: 5V, GND resistance is too small (below 50 ohms). 3 Power-on Check:

For the board that is clearly broken, you can slightly increase the voltage 0 5 1V, and use the IC on the handwashboard to heat up the chip in question after turning on the machine, so as to perceive it. 4. Logic pen check: check the signal presence and strength of each end of the key suspect IC input, output and control pole.

5. Identify the major work areas: Most boards have a clear division of labor in the region, such as: control area (CPU), clock area (crystal oscillator) (frequency division), background picture area, action area (people, aircraft), sound generation synthesis area, etc.

This is very important for the in-depth repair of the computer board.

2. Troubleshooting method: 1. The suspect chip, according to the instructions of the manual, first check whether there is a signal (wavetype) at the input and output terminals, if there is no entry or exit, and then check whether the IC control signal (clock) is available, if there is, the possibility of this IC being bad is very large, no control signal, trace it to the previous pole, until the damaged IC is found. 2. Do not remove the one found from the pole for the time being, you can choose the same model.

Or the IC with the same program content is on it, and the power on is observed to see if it is better to confirm whether the IC is damaged. 3. Use tangential and jumper methods to find a short route: If you find a short circuit between the existing signal line and the ground wire, 5V or other ICs that should not be connected, you can cut off the line and measure it again, judge whether it is an IC problem or a board surface routing problem, or borrow signals from other ICs to weld to the IC with the wrong waveform to see if the phenomenon picture is better, and judge the quality of the IC.

4. Comparison method: Find a good computer board with the same content and measure the pins and waveforms of the corresponding IC and its number to confirm whether the IC is damaged. 5 Test the IC with ICTetest software in the microcomputer universal programmer (ALL 03 07) (EXPRO 80 100, etc.).

The red pen is grounded, and the black pen is measured.

This is a profound question!

A multimeter method for measuring a chip.

Test the resistor directly to see if there is a short circuit.