Tip, When ATX power switch dies....

It is a sick feeling when you press the power switch on your computer, and nothing happens. This happened to me, and I assumed the switch itself had died, after swapping the reset button for the power switch (done on the motherboard).

Yesterday evening, my friend and dissassembled my computer to the point we could get to the power switch itself. We found that the power switch itself was good. However, both wires were frayed to the point of broken contact.

This turned out to be an easy repair: cut, strip, splice, solder, and wrap with black plastic tape. Reinstall switch and everything works fine.

So, if this happens to you, you may not need a new switch, or worse: a new case. The switch in this particular model of case is NOT something you can find at Radio Shack.

My computer case, is a SuperCase Full Tower, with 12 drives bays, and it is a very robust case.

My friend had to bring over his soldering iron and solder, since I have neither. He also had to get a new digital camera, which we found at Walmart. That was the first thing we did. It is a Vivitar 7315 (I think the number is correct), 3.3 Mega Pixel and runs on 2AAs (curently on sale).

I have experienced this twice. ATX type - allways under power. Once it was blown elecrolytic capacitor - easy to replace. Second time it was a sort of short circuit. Some resistor lead touched some ceramics capacitor because the resistor was in declined position, bent to the cap. The pcb was fried around these two components. I have not had time to try to repair it yet but have the feeling something else was blown by this too. The boards are usualy made in haste by people who do not care for "cosmetic" issues like straight leads.

Hello Charles,

Glad to hear you were able to get it repaired.

Any idea on how the wires got frayed in the first place?

Tom

One note about power supplies since we are on the subject. If you own a Dell computer, be advised that the pinout for their power supplies are not necessarily standard ATX pinout's. In other words, if your Dell needs a replacement power supply, you cannot just by one and use it.
Now, this information was for Dell's dating around 1996-1998 continuing through somewhere around 2002. The information is not exact, but worth keeping in mind lest you fry your computer. Also, I do not know if this is still the way it is or not. But it would be something to look into should you own a Dell that needs a new power supply.

Here are a couple of reference links:

Dell proprietary (non-standard) ATX power supply

Link #2

Mike

[ QUOTE ]
SilverFox said:
Hello Charles,

Glad to hear you were able to get it repaired.

Any idea on how the wires got frayed in the first place?

Tom

[/ QUOTE ]

Probably got caught between something, since it looked like there was a crimping on both wires.

To think I was thinking that I would have to get 2 cases, instead of just 1. /ubbthreads/images/graemlins/jpshakehead.gif /ubbthreads/images/graemlins/banghead.gif

Mike, my computer is fully home built. Ain't nothing in it from Dull, Mooway, ComPUKE, HP, or IBM.


Oh, that reminds me, our local Walmart is actually carrying some Computer Systems!!

I had an ATX power switch short internally. I just disconnected it and moved the reset switch connector onto the power switch pins on the mainboard as a temporary measure. I then removed the power switch a few weeks later and disassembled it. Turned out to be a stupid momentary contact switch design, and I just had to bend a contact inside a little to fix. It's been working fine for the last 3 years now. /ubbthreads/images/graemlins/thumbsup.gif

Thanks for another tip, BF Hammer! Unfortunately for my friend, he had to do surgery on case (butcher) to install an AT power supply and switch. In the process, he broke his ATX power switch. Then again, the plastic face on the case is badly designed, with plastic standoffs that break if you sneeze wrong. When he upgraded his primary hardware (mobo, cpu, RAM, and video card that I gave him), he had to put the ATX supply back in it. He may need to get a new case.

Fortunately, I didn't, since I really like mine: the full tower is on casters, 2 of which lock. /ubbthreads/images/graemlins/grin.gif Not to mention a far superior plastic face design (no standoffs).

All,
I have repaired a large number of PC type power supplys. Mostly for the video game and NC controler industry.

The above advice is spot on.

Should you have to go inside the PC supply for any reason, watch out!

In some designs there is up to 300 volts of DC on the primary side. The only fuse in the way is the house hold circuit breaker. You don't want to get mixed up in that. It' hurts. Ask someone who has done that.

Secondly these units are almost all high frequency switching supply's. 300 volts of swinging voltage at 30khz will leave a real bad RF burn. Another thing I don't recomend.

So show a care here.

Be safe
Jack Crow in Iraq

every pc psu i have repaired had a line fuse.
but just the same like jack said watch out!
on 120vac most use a doubler making +380 dc at the filters.
many manufacturers cheap out and leave out the bleeder resistors so those caps can stay charged for weeks.
they will kick you flat on your *** if not kill.