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HP Pavillion a712n desktop problem
How to remove on/off button and troubleshoot or replace. Currently it sticks when pushed in, it would sometimes pop back to regular "on" postion and power up and process..now it will power up but won't processs, sometimes get the error screen that that starts the countdown to start in normal mode but after countdown to zero..nothing happens,, I'm not a comp wiz but a all around DIY'er with everything else so now it's computer time. Just don't want to destroy any components while trouble shooting. Think I just need to replace On/OFF button. Any help greatly appreciated. Thanks,Randy |
#2
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HP Pavillion a712n desktop problem
For an ATX power supply you need a 'momentary contact switch' such as this one-- http://www.radioshack.com/product/in...entPage=search |
#3
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HP Pavillion a712n desktop problem
Rboats wrote:
How to remove on/off button and troubleshoot or replace. Currently it sticks when pushed in, it would sometimes pop back to regular "on" postion and power up and process..now it will power up but won't processs, sometimes get the error screen that that starts the countdown to start in normal mode but after countdown to zero..nothing happens,, I'm not a comp wiz but a all around DIY'er with everything else so now it's computer time. Just don't want to destroy any components while trouble shooting. Think I just need to replace On/OFF button. Any help greatly appreciated. Thanks,Randy The front panel of your computer, will have four or five twisted pair wire things, coming from the panel to the motherboard "PANEL" header. On my computer, the wiring looks like this. Separate wire pairs, and much easier to deal with when maintenance is required. http://imgs.inkfrog.com/pix/sceusa/CASE_FRONT_wires.jpg What you'd notice, if that was the case, is that the "RESET" and "POWER" switch connectors, are the same shape, and are 1x2 connectors. Both the RESET and POWER switches are "momentary contact" type. And that means, you can unplug the "POWER" one, unplug the "RESET" one, and push the "RESET" one into place, where the "POWER" one used to be. Then, when using the front panel controls on the computer, the tiny RESET button performs the power on/off function. You can forget about the reset function, as it is optional for the moment. That's the quickest way to get the computer running again, if the POWER button itself is busted. As the other respondent "rb" says, a momentary contact switch type is what you want. The fun part, is getting it connected (if you want to replace the button itself). ******* On things like pre-built computers, instead of individual wire pairs, you may notice a "monolithic block", like a 2x4 or a 2x5 or the like, which slides as one unit, onto the motherboard PANEL connector. That's a little less convenient to deal with. They do them that way, to speed up the manual assembly procedure when constructing the computer at the factory. To change the wiring in the polyester black shell, you can lift a tab on the side of the block, to release the pin and allow it to slide out. This only works, if the polyester shell uses tabs of that type. In this case, you'd move the RESET pair of wires, into the position the POWER pair used to take. Total of four tab manipulations, two to release the POWER wires, two to release the RESET wires, and then push the RESET wires into the POWER holes. Front panel switches are not polarized, so on a wire pair, it doesn't matter which lead goes in which hole of the pair. (LEDs on that connector, *are* polarized, and you have to be more careful if rewiring LED indicators in the block.) http://www.frontx.com/head_con.html The "lifting of tabs" thing is only required, if the PANEL wiring assembly is one monolithic block and the wire pairs are not separable. If your computer actually has individual 1x2 connectors, the switching of the wiring will go much faster. ******* You can find sellers on Ebay (likely in China), who will sell a wire assembly and switch, ready to use. http://www.ebay.com/itm/PC-Case-Fron...em3a6a4d 2b34 That would work, if you had the individual wire pairs kind of computer, as you could then install a new switch, and plug the 1x2 connector onto the appropriate pair of pins on the PANEL header. Radioshack isn't likely to carry an exact assembly like that, but a local computer store may have them. I have several computer recyclers in town, and that would be another place to look for a reasonably priced solution. You could even bring in the switch in your current case, for a visual match of dimensions (better chance it will fit). I leave the buttons hanging down from my current case. They're not in the holes in the front panel. That makes it easier for me to remove the front panel to replace optical drives and the like. My LEDs are actually mounted in the metal frame of the computer, so when the panel comes off, there are only "light pipes" in the plastic, to couple the light from the LED, into the front panel indicators. That way, my panel has no wires at all on it any more. But I do have an unsightly power and reset switch, hanging down from the sides of the computer :-) For that quality, ghetto look :-) It could be, that by easing the switch out of the panel, and leaving it hanging down, the switch won't bind and will work smoother. You never know... Paul |
#4
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HP Pavillion a712n desktop problem
Rboats;1320047 Wrote: How to remove on/off button and troubleshoot or replace. Currently it sticks when pushed in, it would sometimes pop back to regular "on" postion and power up and process..now it will power up but won't processs, sometimes get the error screen that that starts the countdown to start in normal mode but after countdown to zero..nothing happens,, I'm not a comp wiz but a all around DIY'er with everything else so now it's computer time. Just don't want to destroy any components while trouble shooting. Think I just need to replace On/OFF button. Any help greatly appreciated. Thanks,Randy I pulled off the "broken" pushbutton and just left it with the little "tit" to try to start comp. Now I push the on button "tit" and it tries to start and just turns right off after 3-4 seconds. It just cycles like that. on 2-3 seconds then off 2-3 seconds then off. It just cycles like that til I kill the power source. so whats the problem anyone..I'm a novice here so please be kind...... |
#5
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HP Pavillion a712n desktop problem
On 12/08/2011 05:36 PM, Paul wrote:
Rboats wrote: How to remove on/off button and troubleshoot or replace. Currently it sticks when pushed in, it would sometimes pop back to regular "on" postion and power up and process..now it will power up but won't processs, sometimes get the error screen that that starts the countdown to start in normal mode but after countdown to zero..nothing happens,, I'm not a comp wiz but a all around DIY'er with everything else so now it's computer time. Just don't want to destroy any components while trouble shooting. Think I just need to replace On/OFF button. Any help greatly appreciated. Thanks,Randy The front panel of your computer, will have four or five twisted pair wire things, coming from the panel to the motherboard "PANEL" header. On my computer, the wiring looks like this. Separate wire pairs, and much easier to deal with when maintenance is required. http://imgs.inkfrog.com/pix/sceusa/CASE_FRONT_wires.jpg What you'd notice, if that was the case, is that the "RESET" and "POWER" switch connectors, are the same shape, and are 1x2 connectors. Both the RESET and POWER switches are "momentary contact" type. And that means, you can unplug the "POWER" one, unplug the "RESET" one, and push the "RESET" one into place, where the "POWER" one used to be. Then, when using the front panel controls on the computer, the tiny RESET button performs the power on/off function. You can forget about the reset function, as it is optional for the moment. That's the quickest way to get the computer running again, if the POWER button itself is busted. As the other respondent "rb" says, a momentary contact switch type is what you want. The fun part, is getting it connected (if you want to replace the button itself). ******* On things like pre-built computers, instead of individual wire pairs, you may notice a "monolithic block", like a 2x4 or a 2x5 or the like, which slides as one unit, onto the motherboard PANEL connector. That's a little less convenient to deal with. They do them that way, to speed up the manual assembly procedure when constructing the computer at the factory. To change the wiring in the polyester black shell, you can lift a tab on the side of the block, to release the pin and allow it to slide out. This only works, if the polyester shell uses tabs of that type. In this case, you'd move the RESET pair of wires, into the position the POWER pair used to take. Total of four tab manipulations, two to release the POWER wires, two to release the RESET wires, and then push the RESET wires into the POWER holes. Front panel switches are not polarized, so on a wire pair, it doesn't matter which lead goes in which hole of the pair. (LEDs on that connector, *are* polarized, and you have to be more careful if rewiring LED indicators in the block.) http://www.frontx.com/head_con.html The "lifting of tabs" thing is only required, if the PANEL wiring assembly is one monolithic block and the wire pairs are not separable. If your computer actually has individual 1x2 connectors, the switching of the wiring will go much faster. ******* You can find sellers on Ebay (likely in China), who will sell a wire assembly and switch, ready to use. http://www.ebay.com/itm/PC-Case-Fron...em3a6a4d 2b34 That would work, if you had the individual wire pairs kind of computer, as you could then install a new switch, and plug the 1x2 connector onto the appropriate pair of pins on the PANEL header. Radioshack isn't likely to carry an exact assembly like that, but a local computer store may have them. I have several computer recyclers in town, and that would be another place to look for a reasonably priced solution. You could even bring in the switch in your current case, for a visual match of dimensions (better chance it will fit). I leave the buttons hanging down from my current case. They're not in the holes in the front panel. That makes it easier for me to remove the front panel to replace optical drives and the like. My LEDs are actually mounted in the metal frame of the computer, so when the panel comes off, there are only "light pipes" in the plastic, to couple the light from the LED, into the front panel indicators. That way, my panel has no wires at all on it any more. But I do have an unsightly power and reset switch, hanging down from the sides of the computer :-) For that quality, ghetto look :-) It could be, that by easing the switch out of the panel, and leaving it hanging down, the switch won't bind and will work smoother. You never know... Paul Good answer the reset button is not a good idea anyway if the machine is having problems, if the power button is depressed the system should go into a safe shut down... and if it's totally locked up just killing the ac should do the trick |
#6
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HP Pavillion a712n desktop problem
In a nutshell...the ATX power switch works by momentarily shorting the connection between two pins on motherboard which sends a signal to turn on the PC. A sticky or broken switch can cause a 'no start' or a 'reboot loop' condition. To remove switch: Shut down PC, disconnect power cord. Open PC case. Remove front bezel covering (a tab or screw is usually located on every corner of bezel). Locate the power header(usually a double row of ~12 pins) on motherboard. Two wires, usually green and white designate the power switch leads. Disconnect them from motherboard. Remove power switch from front bezel by removing the screws(if any) then press power switch out of bezel. If it has no screws, it should snap out. A sticky switch could be caused by a bit of grit or grime stuck inside. You can try cleaning the switch with a small amount of rubbing alcohol. -Make sure the switch is completely dry before reconnecting to motherboard header!-. If cleaning does not work, replace the switch using a 'momentary contact switch' such as this-- http://www.radioshack.com/product/in...entPage=search |
#7
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HP Pavillion a712n desktop problem
Rboats wrote:
Rboats;1320047 Wrote: How to remove on/off button and troubleshoot or replace. Currently it sticks when pushed in, it would sometimes pop back to regular "on" postion and power up and process..now it will power up but won't processs, sometimes get the error screen that that starts the countdown to start in normal mode but after countdown to zero..nothing happens,, I'm not a comp wiz but a all around DIY'er with everything else so now it's computer time. Just don't want to destroy any components while trouble shooting. Think I just need to replace On/OFF button. Any help greatly appreciated. Thanks,Randy I pulled off the "broken" pushbutton and just left it with the little "tit" to try to start comp. Now I push the on button "tit" and it tries to start and just turns right off after 3-4 seconds. It just cycles like that. on 2-3 seconds then off 2-3 seconds then off. It just cycles like that til I kill the power source. so whats the problem anyone..I'm a novice here so please be kind...... It could be related to the switch remaining in the closed position. The switch contacts are supposed to be released, after a short push to start the computer. If the switch is smashed and permanently shorted, that wouldn't happen. But the thing is, before you pressed it, it wasn't making contact. The computer did not try to start. Now, when you press the button, the computer misbehaves. To me, that suggests a power supply problem. So if I was fixing it, I'd pursue both possibilities. 1) Examine the power switch, as it comes from the front panel. Two wires go back to the PANEL header. Using a multimeter set to the ohms scale, probe the 1x2 interface of the switch, and see if there is a permanent short (zero ohms) between the two pins. That would tell you the switch is defective. The switch on a computer, by definition, is "momentary ON", meaning normally it is an open circuit or infinite ohms. Pushing the button, shorts the two signals together for a fraction of a second. Releasing the button again, it goes to infinite ohms. If the switch state seems to be properly reflected on the multimeter display, then you know it is not a switch problem. 2) The power supply could have become "weak". Maybe the +5VSB is no long able to stay running, when the computer tries to operate. Maybe the main part of the supply is weak. Or, it could be the PS_ON# signal is sitting between logic zero and logic one, and that has been known to make the main portion of the supply to behave weakly. It can be difficult to assign blame in this case. Normally, you'd start by assuming a faulty power supply (because percentage wise, they have a higher failure rate than motherboards). The thing is, you can't tell by looking at it, whether the motherboard is putting out a crappy PS_ON# signal on the main power supply cable, or the power supply isn't listening to the signal properly. Swapping parts, is one way to test. Rather than waste the time on other test strategies, I'd just swap in a spare ATX PSU and see if that helps. If you're a "scientist type", then you'd study the PS_ON# signal. That would require the purchase of an ATX power supply cable extender (20 pin to 20 pin, foot long cable). You'd cut the PS_ON# wire in two, and that gives access to current flow readings and voltage readings. I might use two multimeters in that case, one in series to measure current, and one set up to measure voltage with respect to ground. Then, I'd monitor what happens when the motherboard doesn't want the supply on (logic 1, greater than 2.0V level and hopefully, pretty close to 5.0V level), versus when the motherboard wants the supply on (logic 0, less than 0.4V level, and closer to zero volts the better the circuit is working). When making logic 0 and logic 1 signals, the circuit will sink or source current, which you would measure with the multimeter that is set to measure current. If you wanted to evaluate the "drive capability" of the PS_ON# motherboard hardware pad driver, you could add a resistive load to the circuit (place load on the PS_ON# signal, on that piece of extension cable). Those are the kinds of things you might do, to determine which end of the link is at fault. Is the motherboard not able to drive a good signal ? Or, is a good signal being driven, but the power supply has a defect that makes it "blind". As you can see, in the time it has just taken me to write that description, I could have installed a spare power supply :-) In any case, those are my two suggestions. If you have a multimeter, check that the switch state is reflected properly on a multimeter set to the ohms scale. If you don't own a multimeter, just swap in another ATX power supply. Doing the "scientist thing", would take half the day, but eventually, you might be able to tell the difference between bad motherboard and bad supply. And instead of spending $50 on a new supply, you'd have spent $10 on a disposable cable, plus whatever precise item needs to be replaced as a result of your "scientific testing". ******* If you need help selecting power supplies, the process starts with looking at the label on the old one. Every number on the thing means something. If you can find a picture of the label, or post a picture on a site like imageshack.us or similar, then perhaps someone here can suggest the nearest equivalent. For example, in this picture, I can see I'm dealing with a Sparkle brand PSU, with model number ATX-400PN. DC Output is 400W. Each rail is specified. If I had the numbers, I could find another, similar supply for sale. http://images17.newegg.com/is/image/newegg/17-103-013-S03?$S640W$ You can substitute a higher capacity supply, for a lower capacity one. The capacity, is the maximum power it can provide. If your computer only draws 100 watts, then 100 watts comes from the power supply, not 400 watts. If your computer needed to draw more power, and kept drawing more power, the power supply would shut off at just a bit more than 400 watts (as it starts to overheat inside). So if you bought a 500W one, and the motherboard draws 100 watts, then there is still just a 100 watt flow from the wall, not 500 watts. The only problem with higher capacity supplies, is their physical size. A 1500 watt power supply, would have a very long casing on it, and would not fit a tiny computer case. And as well, it would cost $$$, so you wouldn't really want to buy one that large. That's for rich guys, with four video cards inside the computer. Paul |
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