My computer was on its last legs recently so I went and bought a new set of basic components for it and went to install them yesterday and it's not booting at all. Components are (all from dabs): Generic 350W PSU ASRock 775-VSTA Mobo Pentium D 820 512MB DDR RAM Sapphire Radeon X550 My question is, if it's not turning on at all, what's it likely to be? I'm aware the PSU is crap and it's just a stop gap for the moment until I can afford a better one, but I was under the impression it would be enough for now. I've tried booting with nothing but the memory and the CPU installed. I don't want to send everything back just for it to be one simple thing. If it isn't booting up at all, is it still possible for me to measure the voltage across the ATX connector on the PSU if it's turned on?
What the 12V rail say on the PSU sticker? Have you tried powering the system up outside of the case? Do the fans start up at all?
I don't know, I shall check later, I admittedly don't have enough experience to know the details about the electrical side of things like this. No - will try that too. No, it doesn't do anything whatsoever - it just sits there as if nothing's changed. Unfortunately it doesn't have an LED display like my old mobo so I can't tell what stage it's got to - is there anyway to tell outside of the fans going?
Without LEDs, if nothing spins up, then it's hard to say. You won't have to disassemble anything to get the PSU info. Just pop off the side of your case and look at that label on the PSU.
Apologies, I wasn't referring to disassembling the PSU in order to find out more (wouldn't dare do that) I meant that as far as the electrical requirements for the mobo/CPU from the PSU go, I'm not too sure. For example what will that tell me?
The amperages (A) is the current in electronics. It's the workhorse. If there's not enough on the rail, then you run into problems. The components are slowly moving to the 12V rail, and the biggest power hogs, namely the CPU and video cards (courtesy of the PCIe interface), are onboard. AGP video cards do not use the 12V, unless the video card requires additional power from the PSU through a power connector. I'm with you on that I do think it's the PSU. There's some 350W that would be fine for your needs, but it's where the amperages are at. If you don't have at least 18A on the 12V, I would definitely say that's where the problem is. There could be some external factors too, but most of them would still have the fan spin up at least momentarily. The only exception would be if the motherboard was mounted without the mounting studs or had one where there wasn't a mounting hole. Something like Fortron/FSP/Sparkle 350-400W units would be the cheapest quality PSU you could find.
Thanks for all your help, just got a couple of questions left: If the ampage isn't enough, would it just stutter to a start and fail or would it definitely stop it from starting at all? (Like all or nothing) I'm fairly sure I had all the screws in place on the studs, I'll check tonight, but if all 6 (I think) aren't in and secured to the mounting studs, would this also stop the mobo from booting (ie. do they form a circuit?)
Have you double checked the power switch and the other wires from your case (HDD LED etc) that you plug into the motherboard. Sometimes I just cant put a sentence together! Heres a pic... http://www.infohq.com/Computer/CompGraphics/AthlonBuild/accessorycons.jpg If nothing is happening maybe the switch isnt doing its job for one reason or another. A single LED would be useful. Have you got a mulitmeter, try seeing if there is any voltage from one of the molex plugs.
Yeah, I've tried reversing the power switch but I'm fairly sure the pin that has the arrow next to it has to be connected to the one which isn't ground. I can't connect the power LED on my case because it's a 3-pin plug (like the one in the picture) but there's only 2 pins available for the power LED switch on my mobo. I've tried just plugging in the power switch both ways round and it doesn't make any difference, no booting. I've got to check the screws/mounting studs again like Big B suggested, would this stop it from booting if they weren't all in, or does it not really matter?
That's true, the switch could be an issue. You just need a flat-head screwdriver to short the two pins for power. Depending on the amps, if it's close but not enough, you probably will get the fan to start up and spin, but it would just stay like that. If it's too low, you wouldn't get it to go.
Besides making sure they're installed, you'll need to make sure that they all line up with a mounting hole. For future reference, it's very helpful to install the CPU, RAM and test power up the motherboard before dropping it in the case. Besides making the heatsink installation easier, you'll know if there's a problem very early on. Of course, if there's no on-board video, you'll want to have one plugged in here as well.
There's not, unfortunately I'm at work now so I'll check all these things when I get home tonight. Thanks for all your help with this, i'll let you know how it goes.
