Mysterious issue with my computer.

[Swe_Richard 1,172]

Hello guys and gals. 

I have an issue with my three year old computer that's been annoying me for some months and has recently turned for the worse. I've built my computers since I was a teen but I have no idea what to do now (well.. I have an idea.. more on that later on in this soon-to-be-wall-of-text).

 

Since I built it it's been working perfectly well. It's a 3770K with a 780GTX, 16gb RAM, 1 SSD and 2 HDD, the mob is a MSI m77 power. All is driven by a modular 850W PSU. It's running W7 ultimate. I haven't clocked it yet as I've not really needed it.

 

Ok. So now the mysterious issue. It's sometimes showing me attitude by refusing to start. Push the power-button on the front and... nothing happens. I then tried flipping the switch on the PSU off and then back on. After doing this a couple of times it starts and everything works just fine for hours and hours. But after I shut down the darned thing the same thing happens when trying to start it later. But not all the time. The latest week it's been more of a hassle to get the thing started though. So I suspect that something is about to give. What could it be?

 

1. PSU? I think it's unlikely. If there's a glitch there I'm thinking the computer shouldn't be so stable once I get it started with varying loads and all that. 

 

2. Mobo? Somehow I suspect this the most. 

 

3. Some odd glitch in the case? Intermittent short? (yeah, unlikely but I'm getting desperate here)

 

As the problem has been more frequent I'm wondering if maybe I should get a new computer (that 6700k looks nice).. If the problem really is the MOBO it seems futile to put money on that. 

 

What do you guys/gals think?

 

 

EDIT: Yeah, another thing. Some of the USB-ports have been working a bit on-and-off lately. I've had issues using my 35mm and medium format scanners with the computer. 

[JWNoctis 4]

Check motherboard for leaking capacitors, see if someone near had a spare PSU and try with that, check contact of power button.

 

Also USB ports had a very limited cycle life, 1500 or so I thought. Maybe seek an USB hub if things get worse.

[CavalierDuck 106]

Richard,

 

Your situation sounds almost exactly like the one I had until a few weeks ago.  The computer was refusing to switch on sometimes, but would then fire up and was mostly OK, although I did see a very occasional unexpected shutdown/restart.  It behaved like this for maybe 2-3 months.

 

What happened a few weeks ago? It completely refused to start. When I pressed the power button the fans made a momentary attempt at starting, then died.  I drew up the same list that you did above, with the PSU being the main suspect (although maybe that was just my hope, being the easiest/cheapest to replace).  I got a replacement PSU, installed it and.... same result, dead PC.  At this point I concluded it was something much more serious (like mobo/CPU) which on a 4-5 year old machine would not be economical to replace, so I'm now enjoying a new 6700K Skylake machine.

 

Sorry it's not better news. I hope someone with a little more hardware knowledge that me can offer something more optimistic, but from my experience what you're describing sounds like a vital component on its last legs and close to failure.

 

My advice would be to make sure you are ready for a possible complete failure.  One bit of good news is that the hard drives were unaffected by the problems of my old computer and are now working fine in the new PC, with all data intact.

 

Good luck!

 

[martin-w 3,235]

It could be many things to be honest. Even a faulty start button.

 

Diagnosing this stuff is a process of elimination. The start button for example can be bypassed. Check that the enclosure switch connector is firmly fitted to the motherboard and not lose. In fact check all cables.

 

For the PSU, I would recommend the Antec PSU Tester. This great little device will tell you immediately if your PSU is healthy. It will give you an LED readout of all voltages on all rails. Obviously, in your case, if the PSU fails to fire up when connected to the tester you will know immediately where the issue lies. Conversely, if it does fire up you will know your PSU is healthy. Testing more than once is advisable in case it's an intermittent issue. I'm not certain it's still available, but there ar5e other manufacturers that make them, like Digiflex for example. Alternatively, a PSU can be tested with a simple test meter, or you can check if it's function by shorting out two of the pins to switch it on.

 

 

http://www.amazon.co.uk/DIGIFLEX-Power-Supply-Tester-Diagnose/dp/B004IO5CT8/ref=sr_1_1?s=electronics&ie=UTF8&qid=1449484579&sr=1-1&keywords=power+supply+unit+tester

 

http://www.amazon.co.uk/GIZGA-Digital-Computer-Supply-Tester/dp/B00Y07BHME/ref=sr_1_1?s=electronics&ie=UTF8&qid=1449484825&sr=1-1&keywords=PC+PSU+tester

 

 

Investigate each potential cause one by one until you find the culprit. As I said, it's a process of elimination.

[nooon 21]

Do you have a physical seven-segment led readout on your mobo for troubleshooting ?

Any error code showing on that ?

 

Ditto for mobo power-on led, do you have any, does it light ?

 

If all lights out, I'd bet on a PSU failure. Can't you borrow a PSU for a test ?

[SteveW 1,792]

I had one do that. I thought might be the power latch on the PSU, but could be anything in the PC tripping it out. Put up with it few a few weeks then wouldn't power on, dead as a dodo. Took out a pair of RAM Modules leaving two, as is a dual channel, and it started up, been fine ever since with half the RAM.

[Swe_Richard 1,172]

Thanks guys for all the input! Greatly appreciated. 

 

This thing keeps eluding me. It seems like the PSU supplies power to the mobo (LEDs on the mob lights up when the PSU is switched on). Kind of leads me to suspect the mobo even more. Might be a faulty capacitor or something to that effect. I'm now beginning to backup everything worth saving. I hadn't really planned to upgrade just yet but I will do this now. Hopefully this one will last me more than three years...

 

Hello 6700K and 980 Ti !