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#21
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new system bootup woes
"Paul" wrote in message ... Adam wrote: "mike" wrote in message ... On 12/16/2014 10:20 PM, Jonathan N. Little wrote: Adam wrote: Host OS: Ubuntu Desktop 12.04 LTS Motherboard: ASUS Sabertooth 990FX AM3+ AMD SATA 6Gb/s USB 3.0 ATX Computer Case: Antec Three Hundred ATX Mid Tower Power Supply: OCZ ModXStream Pro 600W Modular I am having trouble with power to brand new system. After talking with OCZ tech support and doing a simple test, we were able to get the PS fan to spin-up. OCZ Tech support concludes that this is a strong indication that the PS is functional. Next, I suspect that the Antec case's I/O panel wiring to mobo pins may be the culprit. The wiring seems fine to me but still no power. Maybe a loose connection? How to make a stronger connection? If the system powers up to where the power supply fan runs then start looking a the motherboard. Any post codes? Indicator lights on motherboard? Reseat RAM. Check CPU, remove all cards except video (if not using onboard) and see if it posts then. What does your voltmeter say? Oh boy, that's new to me. I'll see if I can find any "how to" links on troubleshooting with a voltmeter. Now you understand why I "bench test" on the kitchen table first, before putting the system in the computer case. You don't absolutely need *any* wiring to the front panel at all, for a bench test. But what I do instead, is keep a push button switch with two connector pins on the end, which slide over the PWR and Ground pin pair. That's for turning the system on. I can also slip a screwdriver tip between those two pins, to bridge them and start the system. That requires a good deal of care and dexterity, and is only practical when the motherboard is sitting on the kitchen table. http://i61.tinypic.com/28bgwf9.gif On the picture there, you can see that header has a "dangerous pair" in the SPKR pin area. Don't bridge that +5V pin if you can possibly manage it, to any adjacent Ground pins. It's another one of those situations where there may be no protective fuse in the path. ******* In the past, some Antecs have had wiring errors in USB or Firewire cables (that's a 2x5 on the motherboard end, leading to a front panel mounted connector). So I would not hook up the front panel I/O wiring at all. On a couple Antec cases here (I have at least three of them), I use the multimeter, set to ohms range, to verify the cable wiring is correct. It's just easier to *not* use Antec front wiring, than be bothered to do that. None of my Antec front USB ports are hooked up, for this reason. I'm too lazy to correct the errors by moving the pins around in the 2x5 end. ******* Okay, I have disconnected the Antec case's front I/O panel USB connector. I take it, OCZ had you do the "unconnected supply" test ? For that one, you bridge PS_ON# to GND on the ATX cable. Bringing the logic level low on PS_ON# is what makes the supply fan spin, and the main supply section to function. On page 37 here, that would be the green PS_ON# wire, to an adjacent black GND wire. Some people recommend connecting a dummy load to the supply, in the form of an old (scratch) hard drive or something that draws a similar small amount of power. http://www.formfactors.org/developer...public_br2.pdf ******* Yes, the "unconnected supply" test sounds like what I performed. Short the green wire to a black/gnd wire in order to test that the PS fan spins. This is a simplified model of the ATX supply. There are two power generation circuits, and +5VSB is separate from the rest. AC Input ------+--- +5VSB circuit | +--- +3.3/5.0/12V main section When you switch the supply on at the back, the +5VSB starts to produce power immediately. The fan will not be spinning at this point. The +5VSB provides 2 to 3 amps max, and is used as a supervisory voltage, amongst other uses. The ATX power supply is convection cooled at this point, when removing heat from the +5VSB circuit. Due to the modest capacity of the +5VSB, it doesn't get too warm. When the ATX power supply main cable has PS_ON# and GND brought together, that grounds the pullup resistor on PS_ON#. Normally, with a voltmeter, you'd see 5 volts level on PS_ON#, and it's when that level is grounded that the supply runs. The fan begins to spin, and the main voltages begin to be produced. The motherboard would be starting to POST at this point. The case fans would be spinning. If you attempt to start an ATX supply, and you see the PSU fan "twitch" about a half inch of rotation, that means the supply tried to start, but encountered a serious short circuit (current overload) on the outputs. To protect against burning any cables, the ATX supply has latched off. Normally, you'd need to switch off at the back, wait 30 seconds, switch on again, to make another attempt to start the system. The reason the supply "twitches", is the overcurrent is disabled for the first 35 milliseconds, until the PSU has had a chance to charge the output capacitors, and that allows the fans to receive current for 35 milliseconds. The fan blades can only "twitch" in such a short time frame. If the "serious short" is present, when the overcurrent detection is enabled at 35 milliseconds, the power supply immediately shuts off the main section. (The reason you wait 30 seconds, is to give any inrush limiter time to cool off.) In this diagram, the +5VSB is used to power the control circuits. The motherboard logic "latches" the momentary logic low level from the front panel switch, and drives out a "steady" 0.0V level on PSON#. And that's what is used to control the ATX supply. +5VSB (0.0V level +5VSB | means "run please") | Pullup \_ Pullup Resistor \ Resistor | PS_ON# | PWR X----+---- Motherboard ---- Open -------------------+- ... control / logic Collector (to of main | GND X----+ Driver ATX + PSU | | supply) | section (Front GND GND Panel Switch - normally open, momentarily close to operate) By removing any USB panel header or Firewire panel header wiring from the front panel to the motherboard, you're removing a possible place for electrical shorts to happen. Wiring up the PWR button from the front of the case (two wire twisted pair labeled PWR and GND), gives you enough control to turn the system on and off. ******* Okay, the Antec case's front I/O panel USB connector is no longer connected. On an Asus motherboard, there is a green LED which is wired in such a way as to monitor for +5VSB. If the ATX PSU is supplying +5VSB, and the main PSU cable is wired up, the green LED should be glowing. And the LED should not flicker. It should be a solid level for the entire time that the switch on the back of the ATX supply is in the ON position. Asus provides the LED, to tell you when it is safe to work inside the PC. The LED must be completely extinguished, before you work on RAM DIMMs or pull PCI Express cards, that sort of thing. It takes up to 30 seconds for +5VSB to drain, after the ATX PSU is switched off. Paul Okay, sounds like what the mobo manual calls the standby power (SB_PWR) LED, which lights up no problem whenever mobo is connected to PS so far. |
#22
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new system bootup woes
VanguardLH wrote:
Paul wrote: When debugging a power problem, at system startup the components don't draw "max power". Even a modest power supply, mistakenly connected to a high power system load, should get you to the BIOS screen. I've seen where an underpowered or weak PSU (they get limp over time) won't power up a system (to the POST screen) that is minimally configured until the HDD is disconnected. Too much power draw on a weak PSU means no boot or unreliable boot despite the PSU's fans will spin. This is true. The very first PC I got (late to the PC game), the power supply on that failed in the limp state. The power supply still operates, and can give enough power to run a 12V @ 0.1amp fan. Any more load than that, and the voltage falls off pretty rapidly. But that supply also had a lot of years of usage on it, so the failure mode isn't a complete surprise. Which reminds me, I took a trip to the recycler last week, and I forgot to load that thing into the car :-) Paul |
#23
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new system bootup woes
"VanguardLH" wrote in message ... Paul wrote: You don't absolutely need *any* wiring to the front panel at all, for a bench test. But what I do instead, is keep a push button switch with two connector pins on the end, which slide over the PWR and Ground pin pair. That's for turning the system on. I can also slip a screwdriver tip between those two pins, to bridge them and start the system. That requires a good deal of care and dexterity, and is only practical when the motherboard is sitting on the kitchen table. If shorting the PWR pins on the onboard front-panel pins doesn't work, and to test the PSU is okay, bypass the onboard logic for soft power up of the ATX PSU. Short the PS_ON line (green wi pin 16 on a 24 power connector, pin 14 on a 20-pin connector) to a ground line (black wire). See pinout at http://www.smpspowersupply.com/connector_atx_pinout.GIF. The signal floats high but the onboard logic pulls that line low to tell the PSU to power up. Shorting it to ground effects the same pull to low state. If done while the PSU is disconnected from the mobo, some PSUs won't power up until they sense a load, so attach an HDD. Front panel power switches can go bad or be defective so the PWR pin short is a good test; however, if that doesn't work, make sure the PSU will come up if its PS_ON line is pulled low. Thanks, the "unconnected supply" test (shorting the green wire to black/gnd wire) passed since the PS fan spins. On a side note, the Antec case's front panel power switches seem really flimsy so I may need to go buy a switch button for PWR-GND pins. Any recommendations? |
#24
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new system bootup woes
Adam wrote:
On an Asus motherboard, there is a green LED which is wired in such a way as to monitor for +5VSB. If the ATX PSU is supplying +5VSB, and the main PSU cable is wired up, the green LED should be glowing. And the LED should not flicker. It should be a solid level for the entire time that the switch on the back of the ATX supply is in the ON position. Asus provides the LED, to tell you when it is safe to work inside the PC. The LED must be completely extinguished, before you work on RAM DIMMs or pull PCI Express cards, that sort of thing. It takes up to 30 seconds for +5VSB to drain, after the ATX PSU is switched off. Paul Okay, sounds like what the mobo manual calls the standby power (SB_PWR) LED, which lights up no problem whenever mobo is connected to PS so far. Make sure any USB loads are disconnected. No iPod or iPad charging. Disconnect the memory card reader. The purpose of doing that, is to try to get as much +5VSB power available as possible. You would check the voltage level on the +5VSB wire of the PSU. With a multimeter set to the 20V full scale range, probe pin 9 (purple) and measure with respect to ground. I use an alligator clip on the multimeter black lead, and clip to a ground screw on the back of the PC to establish the black wire potential. Then, I have one hand free to work on probing with the red multimeter wire. When the 24 pin PSU connector is installed into the motherboard, there is a little clearance where the PSU wire goes into the back of the connector. It's possible to put the tip of the red lead, between the wire and the plastic connector shell. And make electrical contact. That's how you measure the voltage on the purple wire, while the system is in use. The PS_ON# wire, when the computer isn't running, should be pulled high (to the same voltage level as the purple wire you just checked). So now you've measured green. If the voltage is low (and you haven't attempted to turn on the PC yet), then the open collector motherboard driver isn't working right. But you've seen the green LED, which is a first order indicator that it's working a bit on +5VSB. If the LED was dim, you'd suspect PSU trouble. Now comes the fun test. Connect PWR to GND on the motherboard panel header (a momentary touch is enough). The fans should all start to spin. If they don't, and you really think you were successful in grounding the PWR pin, now you go back and check the PS_ON# green wire. It should drop to 0.4V to 0.7V or so. That is the open collector motherboard driver, pulling the line low and asking the power supply to turn on the main rails. If the PS_ON# signal is still high ( greater than +2.0V ), then the motherboard needs to be replaced (under warranty). If the PS_ON# wire is 0.4V like it is supposed to be, and the PSU doesn't react, replace the PSU. You've already done the "unconnected supply" test, so somehow I don't expect the problem to be an un-reactive PSU. It's more likely at this point, to be a motherboard open collector driver that can't pull PS_ON# low. (Or as Vanguard mentioned, a defective front panel switch.) What's strange about this whole thing, is the failure frequency of this interface. I just don't get it. The motherboard has a couple thousand high tech electrical signals, and that damn low tech signal is the one that fails. They must cover that pin with the two minute functional test at the factory (or their test bench wouldn't turn on), so they must be able to verify PS_ON# drives low, by virtue that the woman doing the testing is able to complete all her tests (in the two minutes allocated). (There was a video available, of that testing process at Asus. That's how I know it's a woman :-) ) Asus used to produce anywhere from 3 million to 5 million motherboards per month, so that 2 minute functional test is one expensive test to carry out. But it's essential. They can do boundary scan structural testing until the cows come home, but a functional test covers things like that PS_ON# signal. Just to prove the motherboard works. It's really a final acceptance test, to make sure as many duff motherboards don't get put into cardboard boxes, as possible. So we're basically checking a couple voltages here. To fault isolate and tell whether the PSU or the motherboard should be replaced. The purple wire runs the Asus green motherboard LED. We want to check that it reads 5.0V +/- 5% or so. The PS_ON# signal, when the system is off, should also be 5V (same voltage as purple). When the momentary switch on the front is pressed, the PS_ON# voltage drops. And using your multimeter on the green wire, verifies it dropped to around 0.4V or so. It won't drop to zero, because the driver doesn't go all the way to exactly zero. It just has to pull low enough, to be well below the 1.5V to 2.0V threshold on the thing receiving the signal. +5VSB (0.0V level +5VSB | means "run please") | Pullup \_ Pullup Resistor \ Resistor | PS_ON# | PWR X----+---- Motherboard ---- Open -------------------+- ... control / logic Collector (to of main | GND X----+ Driver ATX + PSU | | supply) | section (Front GND GND Panel Switch - normally open, momentarily close to operate) On some supplies, if the PS_ON# signal rides around 1.5V to 2.0V (in other words, right on the threshold), the power supply actually comes on half-way. This leads to weak rails, and an inability to supply full load current. Apparently, the on-off control isn't as "digital" as it should be. So if the supply appears limp, sometimes it's not actually the supply. And this is an important reason to be measuring the green wire, and that it's driven to 0.4V or less. Otherwise, the wrong component could get the blame. And this whole procedure is for "fault isolation", identifying the defective part. Paul |
#25
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new system bootup woes
"Jonathan N. Little" wrote in message ... Adam wrote: "Edmund" wrote in message ... On Tue, 16 Dec 2014 22:00:51 -0800, Adam wrote: Host OS: Ubuntu Desktop 12.04 LTS Motherboard: ASUS Sabertooth 990FX AM3+ AMD SATA 6Gb/s USB 3.0 ATX Computer Case: Antec Three Hundred ATX Mid Tower Power Supply: OCZ ModXStream Pro 600W Modular I am having trouble with power to brand new system. After talking with OCZ tech support and doing a simple test, we were able to get the PS fan to spin-up. OCZ Tech support concludes that this is a strong indication that the PS is functional. Next, I suspect that the Antec case's I/O panel wiring to mobo pins may be the culprit. The wiring seems fine to me but still no power. Maybe a loose connection? How to make a stronger connection? Any ideas? Normally there are some leds on the mainboard giving info about its status. Sometimes this is found in a manual..... Stronger connection??? not likely the problem. Edmund Thanks, yep, I was looking through the mobo manual and there are CPU_LED, DRAM_LED/MemOK button, VGA_LED (which is completely blocked once video card is connected ), etc. Will be checking those out later. Also most motherboards have a speaker pins on the front panel header, and they include a little speaker dongle that if you connect it you can get post beep codes that can help. The Antec case did not come with a 4-pin mobo speaker for post beep codes so I bought one. But, the orientation is not clear. There are only two actual wires (one red and one black separated by two blanks/GND?). Connecting the black to "Speaker" pin and the red to "+5V" pin makes orientation consistent with the other connectors. Hope my guess is right. :-) As someone else mentioned did the CPU fan start? LED on motherboard light up? HD spin up? Monitor get a signal or NO SIGNAL message? No, I did not get CPU fan to spin yet. Still cannot PWR ON the system. Antec case's POWER button seems flimsy. Will try a switch button instead. Yes, standby power (SB_PWR) LED lights up no problem whenever mobo connected. Can't see VGA_LED once video card is connected. Poor LED placement on mobo. Not sure about the other tiny LEDs yet. Haven't been able to power ON the system. No, no drives (HDD, DVDs, etc.) are connected yet. Just the bare minimum. No, I haven't gotten to video signal yet. Can't power ON yet. I shall never take fans spinning for granted again. :-) As I said you should try with minimal connections...remove everything except video and the connection to the "pwr sw" pins on the front header. This narrows your search. OCZ tech support made sure that I disconnect everything except for one HDD yesterday. I've reconnected the video card. -- Take care, Jonathan ------------------- LITTLE WORKS STUDIO http://www.LittleWorksStudio.com |
#26
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new system bootup woes
"Jonathan N. Little" wrote in message ... Adam wrote: Host OS: Ubuntu Desktop 12.04 LTS Motherboard: ASUS Sabertooth 990FX AM3+ AMD SATA 6Gb/s USB 3.0 ATX Computer Case: Antec Three Hundred ATX Mid Tower Power Supply: OCZ ModXStream Pro 600W Modular I am having trouble with power to brand new system. After talking with OCZ tech support and doing a simple test, we were able to get the PS fan to spin-up. OCZ Tech support concludes that this is a strong indication that the PS is functional. Next, I suspect that the Antec case's I/O panel wiring to mobo pins may be the culprit. The wiring seems fine to me but still no power. Maybe a loose connection? How to make a stronger connection? If the system powers up to where the power supply fan runs then start looking a the motherboard. Any post codes? Indicator lights on motherboard? Reseat RAM. Check CPU, remove all cards except video (if not using onboard) and see if it posts then. No, not the system, literally the only device connected to the power supply was just a HDD (no mobo or anything else). OCZ tech support just wanted to see if the PS fan will spin-up, which it did. Next, I connected the mobo with CPU and RAM (but no video card). OCZ tech support didn't want the video card connected. Then, the PS fan no longer spins. -- Take care, Jonathan ------------------- LITTLE WORKS STUDIO http://www.LittleWorksStudio.com |
#27
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new system bootup woes
"Dustin" wrote in message 33.145... "Adam" Wed, 17 Dec 2014 07:45:38 GMT in alt.comp.hardware.pc-homebuilt, wrote the following message: "mike" wrote in message ... On 12/16/2014 10:20 PM, Jonathan N. Little wrote: Adam wrote: Host OS: Ubuntu Desktop 12.04 LTS Motherboard: ASUS Sabertooth 990FX AM3+ AMD SATA 6Gb/s USB 3.0 ATX Computer Case: Antec Three Hundred ATX Mid Tower Power Supply: OCZ ModXStream Pro 600W Modular I am having trouble with power to brand new system. After talking with OCZ tech support and doing a simple test, we were able to get the PS fan to spin-up. OCZ Tech support concludes that this is a strong indication that the PS is functional. Next, I suspect that the Antec case's I/O panel wiring to mobo pins may be the culprit. The wiring seems fine to me but still no power. Maybe a loose connection? How to make a stronger connection? If the system powers up to where the power supply fan runs then start looking a the motherboard. Any post codes? Indicator lights on motherboard? Reseat RAM. Check CPU, remove all cards except video (if not using onboard) and see if it posts then. What does your voltmeter say? Oh boy, that's new to me. I'll see if I can find any "how to" links on troubleshooting with a voltmeter. huh? Oi... You really should do that when you have the chance. it's a handy tool and skill to have. Yes, sir. -- My truck does not leak. It's just marking its territory! |
#28
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new system bootup woes
On 12/17/2014 10:53 AM, Adam wrote:
"DecadentLinuxUserNumeroUno" wrote in message ... On Tue, 16 Dec 2014 23:45:38 -0800, "Adam" Gave us: "mike" wrote in message ... On 12/16/2014 10:20 PM, Jonathan N. Little wrote: Adam wrote: Host OS: Ubuntu Desktop 12.04 LTS Motherboard: ASUS Sabertooth 990FX AM3+ AMD SATA 6Gb/s USB 3.0 ATX Computer Case: Antec Three Hundred ATX Mid Tower Power Supply: OCZ ModXStream Pro 600W Modular I am having trouble with power to brand new system. After talking with OCZ tech support and doing a simple test, we were able to get the PS fan to spin-up. OCZ Tech support concludes that this is a strong indication that the PS is functional. Next, I suspect that the Antec case's I/O panel wiring to mobo pins may be the culprit. The wiring seems fine to me but still no power. Maybe a loose connection? How to make a stronger connection? If the system powers up to where the power supply fan runs then start looking a the motherboard. Any post codes? Indicator lights on motherboard? Reseat RAM. Check CPU, remove all cards except video (if not using onboard) and see if it posts then. What does your voltmeter say? Oh boy, that's new to me. I'll see if I can find any "how to" links on troubleshooting with a voltmeter. You can buy a multi PS tester for PCs at Amazon or other popular retailer that costs about $7 to $15 and you hook you disconnected PS cable to it, and it gives voltages for all the ATX supply rails in the spec. Easy greasy... http://www.amazon.com/Coolmax-Power-.../dp/B002R06PGE http://www.amazon.com/Coolmax-PS-228.../dp/B004ZPB546 Halfway down the page on the second one is a whole row of them to compare. Thanks, added it to my wish list just in time for Santa. :-) If you intend to build computers, you simply must have a multimeter. Depending on where you live and what coupon flyers you get, Harbor Freight will give you a voltmeter sufficient for your task for free. But I wouldn't recommend any of their offerings if you have to pay for it. Sears has had what looks like a decent multimeter on sale for $10 recently. This link should be in everybody's toolbox. www.pinouts.ru One caution about testing unloaded power supplies... depending on the quality of the design, a power supply with no load on the 5V may have insufficient magnetic flux to guarantee that all the voltages are in spec. You can chase your tail forever trying to fix something that ain't broke. Are you absolutely sure you have compatible ram? I've been in situations where ram that worked fine in one board caused another board to act completely dead. |
#29
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new system bootup woes
"Dustin" wrote in message . 233.145... "Adam" Wed, 17 Dec 2014 06:00:51 GMT in alt.comp.hardware.pc-homebuilt, wrote the following message: Host OS: Ubuntu Desktop 12.04 LTS Motherboard: ASUS Sabertooth 990FX AM3+ AMD SATA 6Gb/s USB 3.0 ATX Computer Case: Antec Three Hundred ATX Mid Tower Power Supply: OCZ ModXStream Pro 600W Modular I am having trouble with power to brand new system. After talking with OCZ tech support and doing a simple test, we were able to get the PS fan to spin-up. OCZ Tech support concludes that this is a strong indication that the PS is functional. Next, I suspect that the Antec case's I/O panel wiring to mobo pins may be the culprit. The wiring seems fine to me but still no power. Take the wiring off the pins. Locate the power pins, touch them both at the same time with a small screwdriver; See if your box powers up. if it does, you've determined the problem is most likely in the panel wiring and you can track it down from there. No, shorting PWR-GND with a small screwdriver didn't work either. -- My truck does not leak. It's just marking its territory! |
#30
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new system bootup woes
On Wed, 17 Dec 2014 12:30:52 -0600, VanguardLH wrote:
mechanic, an inaccurate nym, wrote: Adam wrote: I am having trouble with power to brand new system. So send it back to the shop! He did. Adam *is* the shop. Look at the specs he gave. Did that look like a pre-built or OEM build to you? Didn't get that far - was it any good? |
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