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[Troubleshooting] No beep, no POST, no display

Hey there, my system will power up but will not give any error beeps or output any video :(

History: My build had been performing well for around 7 months until one night it crashed and would not power on again. I determined it was the PSU and had it RMA'd. Now with the new PSU, my system will power on but will not give any display or error code.

Full Story: I followed this guide but I'm getting the same results. I breadboarded my components in order to avoid any possible shorts to the case and worked down the checklist.

* CPU power connector check
* Motherboard power connector check
* Video card fully seated check
* Video card power connectors fully inserted check
* Boot with single stick of RAM/RAM fully inserted check
* CPU installed correctly? (I assume it is, it was working properly before without any tampering)
* CPU fan plugged in check
* System speaker connected check

In addition to the above, I confirmed the monitor works using another source and confirmed the video card functions by swapping it into an older box. I attempted switching the video card into another slot as well as swapping the video card with one that I can confirm works, both to no effect.

I can confirm that the system speaker works, as booting without RAM will elicit an error message. I have attempted a barebones startup with only the MB, CPU, and a stick of RAM and there were no error tones.

I checked if the CPU was receiving power. All four phase LEDs turn on when supplied power.

Finally, when I swapped in my old video card, something interesting happens. During a normal boot, the video card's fan will spin at full speed for a few seconds before reducing to 50% speed for a second before finally falling to an idle speed. When I powered on the card in the current MB, the fan maintains 100% speed and will not fall to a lower speed. Perhaps this indicates an error in the boot sequence?

I would be very grateful if you had any suggestions or insight into this problem. :)

Crucial system specs are as follows:

Part list permalink / Part price breakdown by merchant

CPU: AMD Phenom II X4 955 Black 3.2GHz Quad-Core Processor ($119.98 @ NCIX US)
Motherboard: MSI 870S-G54 ATX AM3 Motherboard ($79.23 @ Compuvest)
Memory: Crucial 4GB (2 x 2GB) DDR3-1333 Memory ($22.99 @ Newegg)
Video Card: Gigabyte Radeon HD 6870 1GB Video Card ($159.99 @ Microcenter)
Power Supply: Corsair 600W ATX12V Power Supply ($61.98 @ Newegg)
Total: $444.17
(Prices include shipping and discounts when available.)
(Generated 2012-02-04 17:11 EST-0500)

*Edited to include note about video card fan speed
10 answers Last reply Best Answer
More about troubleshooting beep post display
  1. The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.

    I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

    Breadboard - that will help isolate any kind of case problem you might have.

    Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

    Make sure you plug the CPU power cable in. The system will not boot without it.

    I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case once you are finished.

    You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

    If no beeps:
    Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

    At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire (standby power supply): 5 volts always on. The green wire should also have 5 volts on it. It should go to 0 volts when you press the case power button (this is also a good way to test the power switch and the associated wiring), then back to 5 volts when you release the case power switch. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

    The green wire should be 5 volts whenever the PSU is plugged in and the PSU switch is on. It will drop to about 0 volts when the case switch is pressed and go back to 5 volts after it is released.

    The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

    You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

    A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

    This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

    If the system beeps:
    If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card (unless you have on board graphics available). In that case, remove any card and connect the monitor cable to the motherboard connector.
    Silence, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

    Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
    At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

    Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
  2. jsc said:
    The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread....

    I had found your guides in another thread, thank you for finding me.

    When I boot just PSU, MB, CPU, and HSF, I get three long beeps. A quick google search shows this indicates a memory error.

    When I add RAM, the system is reduced to silence. Shuffling around the sticks has no effect. Does that isolate the problem to my RAM? What should be my next step?
  3. Do you have another computer laying around or accessible that you can borrow parts from?

    If so, grabbing the RAM from it might not be the worst idea at this point.

    Also, the PSU from it as well. The CX600 isn't that wonderful and in my experience video card fans going haywire often means a bad PSU. It is possible, but unlikely, that you RMAd into a 2nd bad PSU. For that matter they may have sent the old one right back to you.
  4. I had attempted it but the RAM from the old box is DDR2, they won't even fit into the slots :??:

    I tried booting with the PSU from the old box as well, same results with the video card's fan. I tested the RMA'd PSU against one of those little PSU testers and everything checked out. I'll try plugging the RMA'd PSU into the old box for the sake of being thorough.
  5. Plugged the RMA'd PSU into the old box, everything fired up just fine.

    That narrows the list to faulty RAM, MB, or CPU.
  6. Best answer
    PSU testers don't really tell you that much that you don't already know about a PSU.

    For an example, recently the wiring in my house my electric lines had deterioriated to the point they actually snapped in half. We verified with a power tester that there was indeed no power running through a line that powered half the house. We tested the line that went to the other half of the house and it tested normal. Therefore we called the power company and told them to come fix it. They did and it started working again.

    If your PSU is putting out 0 power, that is about all you can figure out with a voltage meter.

    PSUs are so sophisticated these days that they only run out of spec for a millisecond at a time, and even if your voltage meter could measure that change your eye wouldn't be able to register that it changed out of spec for 1 millisecond and then went right back in spec a millisecond later.

    The only thing that can do this is something called a Data Collector. Additionally, you would need an Oscilloscope and a Load Generator. Not stuff most people keep around the house.

    Anyway, the only trustable result from a voltage meter is a result of 0. Other than that, you can't really trust what it is saying about a PSU.

    Also, putting the bad computer's PSU into the old good one and turning it on with a result of working doesn't necessarily mean the PSU is fully functional. It is a good sign, but PSUs (along with all mechanical components, for that matter) deteriorate over time, especially when subjected to the sorts of internal weather conditions common to PSUs (high heat, for instance.

    You could verify that it was fully functional by putting it in a computer with hardware that uses even more power than the broken computer, but I am going to hazard a guess the DDR2 computer doesn't require more juice then your current DDR3 computer does.

    It could be that your old computer uses 200w and your new one 300w, and the PSU is only putting out 250w. Somewhat unlikely since it is straight off a RMA, but it is possible.

    Something to keep in mind, at least. For now, we can probably ignore bad PSU for the time being.

    So, basically, there is no computer you have access to that has parts of pretty much the same level that you have access to, am I understanding that correctly?

    Not a computer from a brother, parent, friend, or anything like that?

    In any event, it does sound like you have done some pretty good tests that does point to RAM as a potential cause of failure.

    That being said, it is important to keep in mind that for most hardware there are two sides to the equation, something giving and something getting you could say. For the RAM it would be the motherboard and the RAM.

    It could be that the RAM is busted and the motherboard can't use it anymore, or it could be that the RAM is fine and the motherboard is busted.

    I am more inclined to think motherboard, because you had a catastrophic PSU failure and it is pretty common for a PSU to take down something connected to it as it goes down. The motherboard was connected to the PSU and also connected to the RAM.

    My gut feeling would be that, but that doesn't mean the motherboard would be the prudent next step in testing, though.

    It would be really nice if you could take your RAM to some other computer that uses DDR3 and see if that computer gave similar problems with your bad computer's RAM in it before you went out and spent money on something.

    Are you sure you can't take it to your work and have your IT guy try it in a spare computer laying around or something?
  7. Raiddinn said:
    PSU testers don't really tell you that much that you don't already know about a PSU.

    For an example...

    That's pretty interesting, it's the kind of info that'll stick with me through my future builds. Having recently taken circuit theory and linear circuits, the thought of PSU's blinking in and out of phase makes my head spin.

    My IT guy (read: a god amongst mortals) loaned me two sticks of RAM matching mine in speed. Tried both of them individually in all slots, reseting CMOS as I went (does it have any effect to do it more than once?) and got the same results. No beep with a stick of RAM anywhere, three long beeps with no RAM :(

    I'll see if I can test my RAM tomorrow, but is it safe to assume that the MB is KIA?
  8. If you tried the IT guy's RAM in your board and it didn't work, that does make it sound like a bad motherboard.

    Here is you an article that talks a little bit about using a multimeter on PSUs that use switching-mode technology
  9. Best answer selected by theFaust.
  10. This topic has been closed by Mousemonkey
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