Computer won't turn on after Shutdown without turning off the power supply for a minute

Question

In the past month, for some unknown reason everything in my PC started to fail one by one. From CPU to hard disk. In the end of replacements and buying new ones, I have this:

• MSI 970A-G46 (new)

• AMD Fx4300 (new)

• MSI AMD HD5770 graphics card (old)

• Cooler Master 450w (replacement-new)

It has been around week or so since I assembled it all. Then this weird problem started to occur. After normal Shutdown(power supply on), I can't get it to start up. If I try within ten seconds, the power led starts blinking. And if I try after a few minutes, the light is on, the fans are running but nothing comes on the screen. Not even bios.

Solution 1

Symptom: PSU rear switch cannot be re-powered within 1 min of previous shutdown. After power down, if the rear psu switch is turned off, the psu can not be restarted unless the rear psu switch remains off (or is unplugged) for 1 full minute.

The psu startup failure occurs every time and is caused by a flaw in the 5v OCP circuit, which prevents re-powering the psu within 1 minute of the previous shutdown.

Attempting to re-power the psu within 1 minute fails because the 5V line has not been discharged quickly enough, thereby triggering the OCP circuit.

The OCP flaw may be a design flaw, or an electrolytic capacitor has failed over time. Some motherboards have similar flaw.

The flaw may also be due to a short, an overloaded circuit, or a power brownout during time of day of peak power usage.

Solutions: -Move power cord to different circuit with less load. -Tidy up cable management to reduce risk of shorts -If a brownout occurs, PSU will shut down and needs to be reset by unplugging it or turning off rear PSU switch for 1 full minute. -Avoid turning off rear psu switch, and in situations where rear psu switch must be turned off, then leave rear psu switch off for 1 full minute before restarting. -Get new modular psu with new caps and new vendor. -Get new motherboard with new caps and new vendor.

=== :~) ===

Solution 2

In my situation, the computer would not start after shut down. Every time I had to turn off the power with 0 button on the power supply. And you won't believe what was causing the problem. Display Port from graphics card. When I plugged in HDMI cable from the graphics card to monitor, all was working well. The issue never happened. Then I unplugged it, and I plugged in Display port cable from the graphic card to display port in the monitor, and baam. The issue happens again (after shut down it won't start).

Display port from graphics card GTX 1070to display port in the monitor was causing the problem. Why? I don't know. My guess is that display port cable tries to take more power from the power supply, and power supply tells, well you won't sir, and shuts down.

Ok, people, connect HDMI cable from your graphics card to HDMI in your monitor. Or if you don't have HDMI, try with a simple VGA port connection to VGA in a monitor.

Hope this will save some of you from headaches.

Solution 3

This kind of thing sounds like a voltage regulation problem and is a telltale sign of bad capacitors. Visually inspect all the capacitors on the motherboard and power supply (taking the PSU apart for this might void the warranty since it's new, so proceed with caution).

On the capacitors you will see a cross or K-shaped seam along the tops. The top should also be smooth and flat, with no bulge whatsoever. If you see a bulge (or if there is a rupture and you see electrolyte crusted on the them), then the capacitor is bad.

Since you said most of these components are new, they should still be under warranty.

Comments

[user]

Sounds almost like inadequate CPU cooling to me, except for that inadequate cooling usually triggers hard shutdowns rather than making the system have trouble turning on. Did you properly apply new thermal grease to the CPU and install the heat sink and fan?

[Raghav Mahajan]

I did. And I have checked the temperatures, they're pretty normal. Around 67 ish .

[kelvinelove]

There might be a problem with the machine's cooling, Machines do this when they overheat