How to use a multimeter to test memory chips
There are 64 data pins on the motherboard and memory, D0-D63. In order to protect the data pins of the memory, a resistor (10 ohms) with no resistance value is added to the 64 data pins of D0-D63 to limit the current. effect. The main principle of the tester is to use the program to repeatedly test each data bit pin of the memory chip to see if there is any breakdown or short-circuited data bit pin, as well as the clock pin and address pin of the chip.
Therefore, when using a multimeter to test the chip, you can also use the method of the tester to measure it. As long as the red pen is connected to the ground (pin 1), the black pen measures the resistance value of the cathode resistance, which is the resistance value of the data bit of the memory chip to determine which chip is broken. , normally each data bit resistance value is the same. But it is still not as intuitive as a tester. This method can be used to measure the quality of DDR memory chips.
According to the instruction manual, the measured memory exists in 2A and 2B, which means single group and double group. But there are 8 16-bit chips, which is equivalent to two groups, and 16 8-bit chips are also equivalent to two groups.
2A is the first group and 2B is the second group.
During the measurement, the data pins of each chip in each group will be tested cyclically. Generally, it is good if it is not broken after 3 times to 5 times. A good chip is: PASS. Bad chips show bad data bit pins.
1. If the test cannot be performed after booting up, there are generally: chip short circuit, PCB board short circuit. The solution is to remove the chip and replace it with a good PCB board to test whether the chip is good or not to see what the problem is.
2. The memory tester does not test the SPD chip, and the SPD chip is optional
3. If the gold finger is burned, it cannot be tested. The chip must be removed and replaced on a good PCB board to test whether the chip is good or bad.
