Shenzhou ares k650d normally enters the system and then flashes the screen for repair

Machine model: Shenzhou k650d

Fault phenomenon: boot normal, normal into the system after splash screen, external connection is normal.

Maintenance process:

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure 1.

Take a look at the machine is a Previously repaired,splash screen fault possibility: screen problems;Screen VCC problem;Screen CLK signal problem;Screen line problem.Step exclusion method.

First, the fault of the screen is still the same, and then the fault is still the same; 2. The measurement screen VCC is completely normal; 3. Measure CLK and signal line completely normal; 4. Screen line problem. Every line has been measured and it is completely normal. I am not sure if a new screen line is sent back, it is still the same when it is installed.

Do you think that the abnormal temperature control card of VCC or the abnormal temperature control card caused by VCC is not normal when measuring?

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure2.

The actual measurement is completely normal. The problem remains when a temperature control chip is replaced. The convert transistor of the Shenzhou motherboard common failing has been replaced, and the BIOS has been swiped, so it is unnecessary to consider those primary faults.After a long time of measurement on the main board, all aspects are completely normal. Before entering the system, it is completely normal. After entering the system,splash screen will start.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure3.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure4.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure5.

Looking at the drawing, I suddenly thought of an idea. Is it caused by abnormal bus communication in CPU or graphics card?Immediately open the drawing to search for SVID. SVID came out of CPU and went to CPU VCC. After measuring for half a day, no abnormality was found.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure6.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure7.

When the CPU is detected to be abnormal, through the two lines H_CPU_Svidclk and H_CPU_The resistance on sviddat signal is used to turn off CPU VCC.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure8.

The actual measurement VCC is normal. To eliminate these two signal problems, let’s measure H_CPU_Svidalrt ා this signal.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure9.

H_CPU_Svidalrt ා this signal is a bus abnormal, alarm signal, measuring resistance diode value is completely normal.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure10.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure11.

Then measure VCC:1

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure12.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure13.

The resistance side is normal, and the CPU end is only 0.447v. Is there something wrong with the CPU that pulls down the signal?Or to CPU signal disconnection?The actual measurements are as follows.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure14.

Take it.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure15.

Then measure the signal VCC 0.987v.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure16.

The oscilloscope measures three SVID signal waveforms.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure17.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure18.

Shenzhou ares k650d normally enters the system and then flashes the screen for repair Figure19.

It can be seen from the oscilloscope that the CPU communicates with the CPU chip VCC through these three signals.

Problem summary: due to the H_CPU_The alarm signal of alsvh is abnormal_CPU_Svidalrt ා signal can not communicate with the CPU chip VCC normally, which causes the CPU to work abnormally and causes splash screen.After normal test, the screen will no longer flash, and the fault is solved.