My PC was working normally until the power cable was accidentally pulled while it was running. Since then, pressing the power button makes it start, shut off briefly, restart automatically, and then remain powered on—but the monitor reports No Signal.
The system has a Gigabyte GA-H110M-H motherboard, Intel Pentium G4560, GTX 1050 Ti, two DDR4 sticks, and an SSD. The keyboard and mouse usually receive power, although the keyboard sometimes loses power for about 10 seconds. Caps Lock occasionally responds, but the computer has also randomly shut down and restarted on its own.
I tested each RAM stick individually in both slots, tested both sticks together, removed and reseated the graphics card, tried the motherboard video output with the GTX 1050 Ti removed, reset the CMOS, reseated the 24-pin and CPU power connectors, discharged the system, tested one monitor, and confirmed that the monitor and cable work. Windows + Ctrl + Shift + B did not help. The board has no diagnostic LEDs, and I do not currently have a speaker for beep codes.
Could the sudden power loss have damaged or destabilized the PSU or motherboard? What should I test next—especially before buying replacement parts blindly?
3 Answers
The PSU is the first thing I would suspect, especially because the keyboard sometimes loses power and the system is restarting by itself. Reseat the 24-pin motherboard connector and the CPU power connector, then test with a known-good PSU if you can borrow one. A multimeter can also help check whether the 5V and 12V rails remain stable when the keyboard cuts out, although a spare PSU swap is usually more practical than relying on voltage readings alone.
Since the Pentium G4560 has integrated graphics, testing the motherboard video output with the GTX 1050 Ti removed is a reasonable step—but only if the cable is connected to the motherboard output and that output supports the connection being used. If both the dedicated card and integrated graphics produce no signal, while the machine also has unstable power or random restarts, the PSU or motherboard is more likely than the monitor or RAM. Testing with a known-good PSU is the best next isolation step.
Make sure the CMOS reset was done completely. Disconnect the PC from wall power, remove the battery, and either short the CLR_CMOS pins according to the board manual or hold the case power button for several seconds to discharge the remaining power. Then reinstall the battery and try booting with the minimum hardware: motherboard, CPU and cooler, one RAM stick, and the power supply. If there is still no video, a motherboard speaker could provide useful beep codes.
Related Questions
Lenovo Thinkpad Stuck In Update Loop Install FilterDriverU2_Reload