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No signal to monitor

By Lisflem
Jul 6, 2011
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  1. Hello all, new to the forum so please forgive me if this isn't the right place to post this.

    The problem I am having is with my son and daughters computers (they have one each). Both of their monitors are reading no signal. I have read through threads etc and will go down the road of checking the motherboard, RAM graphics card etc later.

    What has happened is we are getting a lot of work done to the house and my kids had to take their computers out of their rooms and move them for storage. They have been sitting on our dining room floor for a month and to be honest there has been a lot of dust about (in particular plaster as somebody put their foot through the roof just above where the computers had been stored!).

    We have reinstated the computers but both of them are showing "No Signal" on the monitors. We have tried swapping the monitors with each other and they both show "No Signal". It is a bit of a coincidence that both PC's would breakdown together and don't know if it is something simple that I am missing. Both computers turn on and beep but that's as far as we get as the monitor switches off. All cables correctly connected, could it be something as simple as the dust in them both?

    Sorry to sound such a fool but totally stumped as to why both of the computers would show the same fault at the same time. They are both Zoostorm but bought a couple of years apart.

    Many thanks in advance.

    Lisa
     
  2. Row1

    Row1 TS Guru Posts: 332   +13

    same prob; a couple ideas.

    Hi, Lisa- I have the same prob right now. I tried a couple easy things, but they have not worked, so I am going to have to dig in and try more serious ideas.

    But here is an easy one for you that might work.

    (before you goof around inside the comp, you need to be certain you know how to do it safely - there are components in there that, even when unplugged, can shock and possibly electrocute you; plus, goofing around in there can shock the comp, damaging it from your static electricity.)

    The beep heard when you start the computer actually is a code for something. You can google "POST beep codes," or similar, and figure out what, of five or six messages, the pattern of beeps mean. ("POST" means 'power-on self-test.')

    The usual, brief but cheerful POST one-beep means everything is OK, as far as the hardware of the computer goes: RAM is working, motherboard is working, video is working, and keyboard is detected and working - off the top of my head, I don't know what else.

    If that is the beep you hear, then the motherboard is OK, and the RAM is likely OK. It is also likely that the video processor is OK - the video processor might either be built into the motherboard, or may be a card that is plugged in to the motherboard.

    Either way, it doesn't usually have an effect on the beeps: if you hear the one beep, then the video part of the computer is OK, and the problem is some other mystery - I could only give guesses that would be more confusing than illuminating. You have switched monitors, so that is unlikely.

    If you get two long beeps - they may almost sound like one beep because the gap between the two beeps can be very brief - then, that means that the compuetr is turning on, and doing a self-test, and figuring out that the video part is not working. (the beep lets you know, since there is no way for a message to come on the screen!).

    If the beep pattern is something different, you will have to look at a general guide to "POST" self-check beep patterns, or find the guide to the beep patterns for these computers specifically. As far as I have ever seen, the POSt beep patterns have always been the same across computers.

    If it is two long beeps, then the computer cannot operate the video processor part for some reason. This is totally independendent of whether you have a working monitor plugged in or not (sorry - as you figured out, no easy solution there).

    Somehow, the computer has lost the ability to operate the video. This could either be due to hardware or software failure. Or, possibly, inadequate power coming into the comp - if wiring has been redone, it is possible that the power is not steady enough to push the juice through to run everything. It is also possible your computers have a switch to let you set power - like 120 volt or 220 volt.

    The actual power supply unit in the comp - that converts electricity from the wall into the style needed for the various parts of the comp - could be dying, but i see that as kind of unlikely.

    If so, this could be a problem - but that is a long shot.

    It is probably either a physical problem with the motherboard (dirty, shorted out, bent til some connection broke), the video card (if the card is a separate plug-in) (card is not plugged in properly, is dirty, got twisted and some commection broke),

    OR the problem is that the computer's most basic software instructions, BIOS (basic in-out system) has a setting that does not match your specific video arrangement.

    (this is my problem right now).

    normally, the BIOS can be seen on-screen, and changed, if you press a certain button on the comp before everything else starts up. This program looks like old "DOS" programming, and like a control panel with a lot of choices to go in and change BIOS settings.

    If, somehow, someone changed settings for video, this could cause the problem. But you or the family would pretty much remember goofing with both, and hopefully confess.

    some other quirck may have made a change to BIOS, though. fortunately, there is a fairly easy way to reset BIOS back to the original settings.

    You can chewck online, or any manual, but the thing to do is to "reset BIOS," or "restore BIOS." The easiest way is to carefully remove the little watch battery that is set in the motherboard, keep it out for a half minute, then replace.

    You must figure out if you feel knowledgeable enough to handle this. Even unplugged, electricity gets stored in the computer, in little thnigs called 'capacitors,' and they could potentially electrocute you.

    Also, things may have changed on your comp across time, such as RAM upgrade, and going "back" to original BIOS defaults may induce settings that are not guaranteed to work with the way your computer is, currently.

    Also, it may work, but any subsequent BIOS changes would be lost - like if you had set RAM timing to be differnt from typical default settings.

    So, see how confident you feel. (and don;t blame me for not warning you.)

    It is actually not too difficult to 'reset bios,' and might solve the prob.

    Besides pulling that battery out, there are two oher ways, potentially, to reset bios. The comp might actually have a 'reset bios' button. not too common, but possible.
    It also will almost surely have a 'jumper' to be 'jumped' that, if 'jumped,' resets bios - the benefit is you don't have to worry whether you have kept the battery out long enough. You will have to figure out what a jumper is (google), but then have to figure out exacty the spot to add o move a jumper from one position to another, exact position, then back.

    This makes a final possibility occur to me: the bios battery may be dead, or nearly - with too little power to 'hold' bios settings in the bios memory, leadign to a prob.

    Both batteries could die abt the same time.

    The BIOS chip itself may have died, in which case it is usually way more hassle to locate exact one and replace versus seeking some new/used low-price comp.

    A final prob is that a power flicker or 'spike' in your home put too much electricity thru the comp, and destroyed some little connection - an example is the flicker when a heavy appliance comes on. Comps are usually built to handle the everyday spikes.

    If you are having electrical work done, this could introduce a spike bigger than typical.

    Also, lightening strike. Especially if during construiction/electrical work, when the ground wire (usually in place/connnected) for the home may have been interrupted.

    If the video card is the plug-in type, you can buy a compatible one, and plug that in, and give it a try. you must, however, know whether the vid card is "AGP," PCI, PCI-E, etc.

    If the vid card was the built-in to the motherboard style, you may still be able to buy an external, plug-in one. go cheap since it would just be an experiemtn - vid cards go from $15 to $300+. A decent one can be had for not much more than $15.

    So, the most direct thing would be to try to pull out the BIOS battery, and even replace th battery.
     
  3. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,244   +234

    Yes I would suspect that the CMOS batteries have died causing the bios (basic input/output settings) to change, disabling the present video cards or video settings. Can you try a known good monitor? Do the motherboards have on-board video or a add-in video card? The CMOS battery is a small silver coin-shaped device on the motherboard. They may be CR2025 types, but Europe may be different than the USA regarding this. Replace the batteries and make sure you reset the bios to the defaults once you get any video.

    One note if you could see anything:

    if the batteries are bad the time and date will be way off when the systems were plugged in and first booted
     

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