Colorful 3060 12G is not energized (the resistance of 5V power supply opening circuit is invalid)

Colorful 3060 12G is not energized (the resistance of 5V power supply opening circuit is invalid).

Colorful 3060 12G is not powered on, and the motherboard is directly removed after the street graphics card. First, the major power supply inductors of the graphics card are measured without obvious short circuit. During the measurement, it is found that Q505B has been turned on to pull down the B pole of Q505A, and Q505A has been turned off, but no 2.5V power supply is detected at the upper end of R600 resistor .. The specific maintenance process is as follows:

Fault model: Colorful 3060 12G

Fault symptom: no power supply.

Maintenance process: I received a machine sent by a customer for repair, the model is Colorful 3060 12G, and the fault is that it is not powered on.

Colorful 3060 12G without electricity Figure 1

Remove the motherboard directly after you get the graphics card. First, measure that there is no obvious short circuit in the major power supply inductors of the graphics card, power on and measure the voltage. If there is no 5V power supply, find it.blueprintInquire about the working conditions of 5V and find that 5V is not turned on. Continue to check the drawings and find that 5V EN is controlled by Q505, which is divided into Q505A and Q505B.Triode, controlled by a b.

When the CE of Q505B is turned on, it will pull down the B pole of Q505A to turn it off, and then 12V will be divided by R602 and R600 to generate 2.5V voltage, which will be used as 5V EN to turn on 5V power supply.

Colorful 3060 12G without electricity Figure 2

During the measurement, it was found that Q505B had been turned on to pull down the B pole of Q505A, and Q505A had been turned off, but no 2.5V power supply was detected at the upper end of the resistor R600. The voltage at both ends of the resistor R602 was measured at one end with 12V and one end with 0, and the resistance of the resistor R602 was measured at infinity with an ohmmeter, which was caused by the failure of the resistor R602, so no EN was generated.

Colorful 3060 12G without power supply Figure 3

I found a 100K resistor from the material board and installed it. After power-on measurement, 5EN has been generated, and 5V has also been generated. I installed the graphics card on the motherboard and started the test, and successfully lit it up and entered the system.

Colorful 3060 12G without electricity Figure 4

Maintenance results: the startup test can be successfully lit, and the recording, camera, sound and WiFi are normal when entering the system, and it is normal to carry out the stress test of the roaster for half an hour, so the maintenance is over.