Odd Monitor Issue

Discussion in 'hardware' started by philby, Oct 16, 2012.

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  1. philby

    philby Registered Member

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    Hello All

    Went out to a chap today who was getting the 'No Signal' routine on his monitor (box was relatively new Acer...4GB, i3 etc).

    Swapped out monitors and VGA cables - same problem. Then, I put a cd in his OD to try booting into WinPE and suddenly it worked - but only after a bizarre 'chirp' (not POST beep) from the box!

    I was then able to reboot about 10 times, with either monitor, but then the 'No Signal' message re-occurred and I noticed there was no 'chirp' from the box on this occasion. Unplugging everything at first didn't help, but then did - I got the 'chirp' back and the monitor was back up.

    I took the side of the box off and checked for hair/gunk around the VGA port but everything looked sparkling clean. I left him with the machine up and running and suggested he try an HDMI cable as there are ports on both box and monitor.

    Has anyone ever seen this before - a monitor that will only work if there's a 'chirp' from the box at boot?

    Thanks in advance

    philby
     
  2. Bill_Bright

    Bill_Bright Registered Member

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    The "chirp", or more accurately the BIOS "beep" code of 1 beep indicates the computer successfully completed POST - power-on self test.

    The intermittent failure of the POST to complete indicates something is failing and POST in unable to complete. This could be RAM, the CPU, the graphics solution, or the motherboard itself.

    If me, I would start with power. Failing power could cause any of those components to fail so ensuring you got enough gas, and no water in the tank is important first. So when troubleshooting potential hardware problems, I always start at the wall. Is it plugged in? Turned on? Is the power supply working properly?

    I am leaning to the PSU anyway, because if the CPU or RAM fails, you generally get a different "beep code" - like several long or short beeps, or some combination of long and short beeps - depending on the BIOS maker and the codes used.

    There is no conclusive way for "normal users" to properly test a PSU. That takes a qualified electronics technician using an oscilloscope, or power supply analyzer - sophisticated (and expensive) test equipment.

    I keep a PSU Tester in my tool bag in my truck. The advantage of this model is that it has an LCD readout of the voltage. With an actual voltage readout, you have a better chance of detecting a "failing" PSU, or one barely within the required tolerances as specified in the ATX Form Factor PSU Design Guide (see “Table 2. DC Output Voltage Regulation” on Page 13). Lesser models use LEDs to indicate the voltage is just within some "range". These are less informative, considerably cheaper, but still useful for detecting PSUs that have already "failed". Newegg has several testers to choose from. However, none of these testers test for ripple and they only provide a little "dummy load", not a variety of "realistic" loads. So while not a certain test, these testers are better than nothing. They are also great when using a spare PSU for testing fans and drive motors as they signal the PSU to turn on when plugged in.

    But typically, the best, and conclusive method for home, normal users to test a PSU is to swap in a known good PSU (that has sufficient horsepower) and see what happens.

    Once you know you are supplying good power, you can move on to other potential causes.

    I am assuming while you were digging around inside you ensured all cable connections and cards were securely connected, and not loose.
     
  3. kdcdq

    kdcdq Registered Member

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    I concurr and nicely posted Bill.... :) :thumb:
     
  4. philby

    philby Registered Member

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    First Bill, thanks for that superb answer...

    Regarding that 'chirp' - it really doesn't sound like a POST beep at all - could this just be that the board speaker is a little cranky?

    As for swapping out the PSU - I would if I were confident about getting everything unhooked and put back correctly in such a small space (small form factor Acer). I'm not really experienced enough to do this without taking hours to do it and probably messing things up. I will advise the guy as per what you have said, however, and get him to take the machine to someone higher up the hardware food chain than me!

    Thanks again for your help

    philby
     
  5. Bill_Bright

    Bill_Bright Registered Member

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    Thanks for kinds words, guys.

    It is impossible to say without knowing exactly what is making the noise. If the sound is coming from the speaker, and the beep itself does not sound normal, then again, I think I would look at power first.

    But noises can come from fans, drive motors, or other mechanical things in drives. Capacitors can squeal too and is generally a sign of failure coming. So the source of the noise matters.

    Swapping out a PSU is technically fairly easy. All the connectors fit just one way so with care, it is hard to mess up - if you can see in there while your hands are in your way - a problem even for experienced users in SFF cases. But still, it is easy to miss a connection or knock something loose in the process so it is always nice to have someone else but yourself to yell at if the repair goes wrong. ;)
     
  6. philby

    philby Registered Member

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    Bill, given that (inadequate / inconsistent) power supply may well be the cause, is it worth suggesting to the user that he skip the 4-socket mains extension he's using and plug the box directly to the wall socket to test?

    Or does the use of such an extension have no impact on inadequate / inconsistent power issues? I.E. suggesting this to him would be pointless?

    Thanks

    philby
     
  7. Bill_Bright

    Bill_Bright Registered Member

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    If it is just a plain old extension cord, I don't see a problem. But if it is a surge and spike protector, it might have taken one too many hits and might be worth checking out - just to eliminate it from the equation. That said, if that cord supplies power to the monitor and other devices too, and they seem to work fine, then I doubt it is the cord.

    Again, not likely - assuming the cord is not physically damaged, and not 300 feet long either.
     
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