Possible PSU failure?

[Chris_p1]

Hello

I am new to these forums, looks like it could be a good source of help (and supplies!)

My Dell 8700 desktop (about 8 or 9 years old) won't power up. When I press the main power on button, nothing happens at all. It has been playing up for a few weeks in that sometimes it works when I press it, and sometimes it doesn't, needing 3 or 4 goes typically, or maybe a different type of press, harder, longer, shorter....basically the button has felt unreliable. Physically it seems OK, there is a click there like there always has been. Has felt a bit random, in terms of whether it starts up or not. Now, it doesn't want to turn on at all.

There is an orange light on inside the case, and the green test button on the outside of the power supply works OK.

I have replaced the button battery, tried taking USB devices out, and the graphics card, and have removed the two connectors that feed into the area/box where the power button is, before replacing them immediately to check if there was a loose connection. Still the same.

Could it be that a new power supply is necessary?
If I go that way (don't know much about them), do they come with instructions to point me to where I should plug each mini-plug? They have a lot of wires! One to to the SDD, one to the....etc etc. Maybe it would be more straightforward than I imagine. I'm now getting in to areas I don't really understand very well and am slightly nervous about fiddling, on the other hand I'd like to fix this computer and keep it going.

The only other symptom I have noticed is that twice in the last few days I've been working and the monitor turned blue! Not a typical blue screen of death with a Windows message, just all blue.

I wondered what else I could try next to fix it. Is buying a new PSU worth a go I wonder. I'd probably go cheapest possible, but I'm here to ask advice. The current PSU is rated as 460W.

Thanks for any help, much appreciated.

 

[mickyflinn]

Hi and welcome.

First thing you need to determine is if the start button is faulty, they can be had used for about £15.

You can jump the start pins on the motherboard but depends on how confident you are and finding the correct pins to start.

 

[Chris_p1]

Thanks mickyflinn! Currently not confident doing that, unfortunately! Not sure what tools I'd need and where to look, as you say.

I wonder what is more likely to go, the power button or the PSU. I think the PSU, but it's a hunch more than anything. Partly as I've never heard of power buttons needing replacing, but also that my screen has turned blue a couple of times recently..

 

[mickyflinn]

Thanks mickyflinn! Currently not confident doing that, unfortunately! Not sure what tools I'd need and where to look, as you say.

I wonder what is more likely to go, the power button or the PSU. I think the PSU, but it's a hunch more than anything. Partly as I've never heard of power buttons needing replacing, but also that my screen has turned blue a couple of times recently..

Blue screening us more indicative of memory problems, you have you got to start somewhere.

Power supply you have sone lights on the motherboard which means some power is there , but still could be faulty.

It's a case of where to start and what do you change because of cost.

 

[Chris_p1]

Hello. So I jump started it! Does this mean that it is probably the button, and not the PSU?

I think I have seen the part you mean - so it's the button and the cable that leads to the motherboard. Will it be easy to fit myself I wonder. It's getting very deep into the innards of the case.

I've got this far though....!

 

[mickyflinn]

Hello. So I jump started it! Does this mean that it is probably the button, and not the PSU?

I think I have seen the part you mean - so it's the button and the cable that leads to the motherboard. Will it be easy to fit myself I wonder. It's getting very deep into the innards of the case.

I've got this far though....!

It does look like the button if alls working well after jumping the pins , itshould be easy enough to change but it is a Dell

Google images is your best bet or dell community.

 

[EsaT]

Most symptoms would fit to both failing switch and capacitors.
But faulty switch shouldn't be able to cause such not complete shut down crashes.
Either it doesn't contact and nothing happens, or it contacts causing sending command to PSU leading to either kind of reset or shutdown.
BSOD/crashing is more toward area of unstable voltages or some component.

Dell is infamous for using non-standard PSUs, so finding fitting PSU to test likely isn't easy.

There is an orange light on inside the case, and the green test button on the outside of the power supply works OK.

Only absolutely certain thing those tell is that there's enough volts to light it up, but not enough to turn it to smoke emitting diode.

Hello. So I jump started it! Does this mean that it is probably the button, and not the PSU?

Unless measured using oscilloscope and preferably with also load, it's impossible to know if voltages are stable and ripple inside specs.

 

[Chris_p1]

Thanks! I fixed it with an external button with cable linked to that but that I jump started.