[Resurrected! ] How to turn on a Desktop PC?

Madasa said:

I'll get the switch repaired when I can.
Question removed.

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Just a suggestion: don't delete it!

I didn't see it in its original version, but I've deduced that your problem turned out to be the switch. The thing is, someone else may come along with the same symptoms you had, and learning that the switch needed to be replaced could be helpful for them.

MoodyBlues said:

Just a suggestion: don't delete it!

I didn't see it in its original version, but I've deduced that your problem turned out to be the switch. The thing is, someone else may come along with the same symptoms you had, and learning that the switch needed to be replaced could be helpful for them.

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...and here I thought you were going to say that if it was a Windows PC, being unable to turn it on is a security feature.

Seriously, I agree to leave it in place. Always useful in the future for the users who might use the search feature.

rootabaga said:

and here I thought you were going to say that if it was a Windows PC, being unable to turn it on is a security feature.

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Bwaaaaahhh!

You do know me well.

Madasa said:

Electrical connection issue.

I keep a 2004 desktop because I love the ripped cd audio sound from the 7200 rpm hard drive, coupled with an audio enhancer only out on XP. (using Grado headphones).

My Lenovo Thinkpad Laptop and Nokia phone have completely uninvolving sound by comparison, so I miss it, though I listen to music less than I used to.

Developed a front switch issue, intermittent at first. I can't transport it to a previous good repairer without a car now and funds are low for a few weeks.

When it's working normally, and the mains override? switch at the back power socket is left on, it would only come to life when I depress the circular front switch with a back light (blinks slowly on Standby, lit when running).

Now when I switch on the mains switch at the back, the fan comes on and the light behind the large front power button fizzes silently. The hard drive doesn't spin. The button physically clicks in normally but never turns on the pc. (except occasionally at first).

I guess it's a soldering or motherboard issue. I can't get into the front plunger type switch mechanism between two panels, just the wires inside the case.

Any simple fix? Thanks for reading.

View attachment 153501 View attachment 153502 View attachment 153503 View attachment 153504 View attachment 153505 View attachment 153506 View attachment 153507



Yes! Old and dusty!
I know I am, as is the inside of this pc

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My thought for a PC from 2004, is possible capacitor problems. Because that was around the time of the capacitor plague.
https://en.wikipedia.org/wiki/Capacitor_plague
And I had a main-board fail with bad caps, that was originally bought in 2003.

You may want to visually inspect your desktop main-board for signs of any caps in distress, like bulging or leaking.

If the whole computer is from around 2004, could also bad caps in the power-supply.

Sometimes bad electrolytic caps don't always show visual signs of failure, and can only really be tested properly with an ESR meter.

The symptoms I had with mine, was system instability with unexpected crashes, as well as it sometimes wouldn't turn on.

I guess I missed that with the one I built in 2009, Still going strong running Manjaro.

Davdi said:

I guess I missed that with the one I built in 2009, Still going strong running Manjaro.

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As is my 2004 HP running Kubuntu.

@Madasa...

Please read through this before you actually do anything and post back with any questions if you're unsure about it.

The front cover will actually come off. It's probably got a few "hidden" plastic tabs/tangs accessible from just inside that metal frame and it will either snap loose completely or be hinged on one side.

Once it pops off you'll be able to see clearly which wires go to the power switch. Make note of them.

FWIW, the I/O switch on the back of the Power Supply simply turns it on and energizes its coils. I am pretty sure that is an ATX power supply and it looks to be pretty generic. Hard to tell since there is not enough detail in the pics especially of the connectors and the MB layout.

Once the PS is turned on via that I/O switch, the transformer comes to life so it's ready to go, and just a wee circuit on the MB is powered. When you press the power switch, it simply closes that circuit on the MB (think of it like a relay), which then fires off the rest of the circuits and power is supplied both to the MB as well as the drives, fans, ports, etc.

There are roughly three possibilities. The easiest to check is the front panel switch itself. Once you figure out which pair of wires goes to that switch (pop off that front cover!), trace them to the motherboard. They will connect to two little metal posts and should just have a little connector for them. Turn on the I/O switch, then NOTE CAREFULLY where those two wires attach, then lift up the connector. You should not have to remove it all the way, but if you do, that's the "note carefully" part so you don't miss where it belongs. Once you have exposed the bottom part of those two posts by lifting the connector a little, you can then use a very small piece of metal (tweezers are fine but you can probably also use a straightened paper clip) with the end you hold covered by electrical tape -- this circuit is very low voltage and current, but just in case you touch something you shouldn't -- and short those two posts (and only those two!) together. That's the same thing as what the switch is (or should be) doing.

If you hear lots of "familiar" noise then you know the problem is the front panel switch. Most are just a momentary on/momentary off, so you can find a suitable replacement online. It won't look pretty but you won't care, right?

If, however, shorting the posts does nothing, push the connector back down, as the panel switch should be okay, and I would next try swapping the power supply itself. A used one is fine, and "generally speaking" you just want an old, basic ATX power supply (easy to tell that one is old because it has no SATA connectors, but it does have a floppy connector). Based on the PN in your pic that's only a 250W, so be sure you get at least that. If you have a computer repair store in your area they probably have a bunch of used ones laying around they'll part with for a song. Make a note of all of your connectors and replace them one at a time. You may not even have to remove your existing one if the replacement one has long enough wires. Once it's all connected, then plug your AC power cord into it, if it has an I/O switch turn that on, then press the front power button while crossing your fingers.

If that doesn't do it, then the third possibility (now almost a certainty) is the mainboard. Since you won't be able to find one (if you do it will be someone like you that has it because they want it, so they won't part with it) and if you do it will be costly, then just buy an old XP computer. They are all over ebay. Then plug your hard drive into it and copy your music files (from whatever drive letter that shows up as) to the C drive on the "new" computer, and you're good to go. Copy them to a thumb drive as well since the drives are always a weak link. Note: You won't be able to successfully swap your drive in place of the drive in another XP computer and have it work, so don't bother trying. Even if it boots it will not be reliable. Just use your old drive to copy off your music and other files you want to keep.

Overall, if it's not that front panel switch, you could just jump to getting another XP box instead of trying another Power Supply. That's probably what I would do in your circumstances (though in mine, I'd dig around in my pile of crap until I found another PS).

Good luck.

Been there, done that, got the T shirt. That's exactly the way I want about it, In my case it was the case switch, but as I had some spare cases, I simply swapped everything over into one of the spare cases.

Madasa said:

@rootabaga
***
If I may I might ask your attention again to understand which end you meant, and the fan coming on when it didn't before - but another time.

I did think those panels would separate further with a screwdriver. I haven't looked for those capacitors yet.
***

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The whole front panel should separate from the frame. It's probably a single casting with indentations, etc.

The fan won't come on until the switch basically signals the "relay" to close and power the rest of the circuits, so fan, drives, etc. Since you said it was intermittent and slowly got worse that does suggest it's the switch and my fingers are crossed for that. The bypass test (shorting the pins on the MB) will answer that in short order.

The end I meant is the mother board end. When you trace the wires you should come to some connectors that will look something like this:



And in fact, looking at that picture, I suspect that the colors will be the same and the pair you want to trace is the green/white set (so you wouldn't have to pull the panel).

This is kind of like how the pins/posts will look on the mb:



So lift the connector off the mb just enough that you can expose the pins that connect to those green/white wires and short them. If it all fires up, you know you have to replace the switch. Cheap and easy.

Good luck with all of it, and stay healthy.