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No video signal (with an interesting twist..) I'm desperate.. Please HELP!


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#1 highrider

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Posted 15 February 2011 - 04:07 PM

Hello all,

OK I know this is a thousand year old question but this is unique in the way it pops out..
So here it goes,

My specs first,
1) Epox 9NPA Ultra+ Mobo
2) Athlon XP 3500+ CPU
3) 1 GB RAM
4) 8800 GTS video card
5) 400 W Silverpower PSU

First time I had the no-signal problem was, after a power outage while watching a movie. Power went off and then I waited for it to come back (There was a spike in the power while I was waiting for the it to come back on btw and power went off instantly again, just to note), when the power came back on I powered on the PC and continued with no probs.( Tomorrow morning, when I turned on the PC the monitor would get no signal at all no matter what I did. But the PC booted and the hard disk loaded the OS. Just no signal from the video card at all.. So I tried everything including;

1) Removing power cable and pressing on button for 30 secs
2) Resetting the BIOS and removing the CMOS battery
3) Removing/moving the RAMs
4) Pulling all the connections out 1 by 1 and try powering on
5) Trying other PSUs to see if the PSU was faulty

But nothing worked so I took it to a service and they told me that my video card (6600 GT back then) was *kind of* faulty meaning it would not work on my PC but it would work on other PCs (?!?) and told me that while it worked on other PCs, it wouldnt mean that it was functional and that it may do the same in other PCs sometime later and advised me to get a new card (because they had tested another PCI-e card on my PC and display was on meaning there was no problems with the PCI-e slot either - I guess-) So I did get a second hand 8800 GTS, plugged it in and voila! It worked without any problems at all.

Then I used the computer for about 2 months UNTIL yesterday where it started to do the same problem out of nowhere (no power outages, no nothing..) No video signal to the computer at all.. I had the old card (6660 GT) lying around so I plugged it in to try it out. It didn't work naturally but the monitor light would turn green for 1-2 seconds before well.. Displaying nothing at all lol.. Then the light would turn yellow. After the second try, it doesnt even do that.

So yeah... This is the problem.. 2 cards and no video signal at all. I dont know how this might help but a couple of thing I noticed this time

1) The PC boots while there is no signal, but I have to press enter at some point for it to continue loading from the Hard drive. Since theres no signal I cant see if theres any message of course.
2) When the PC is booting first the USB mouse and keyboard powers on but after a while their lights goes off and doesnt come back. I dont remember getting this problem first time with the older case.
3) Epox mobo has an on-board diagnostic LED which shows FF (fully functional) after the boot and also it has 3 blue LEDs near RAM slots, CPU and another part I cant remember right now. But they all do light up indicating that there's no problem with those parts either.

While I havent had the chance to try the 8800 GTS with another computer to see if it worked, Im guessing it might since this was the case the first time this problem occured.

This time I cant suspect anything. I mean I am left w/o any thoughts as to what might be wrong, I've tried everything to no avail... It may be the video card, the PCI-e slot, the ram etc etc... I mean what are the odds of this problem happening the second time (I haven't even touched the computer after I plugged the new video card) I cant still pinpoint the problem and I dont have the funds to replace any components anymore. So I'm practically helpless at this point and need my PC for my work.. I would greatly appreciate any comments about this problem. Thank you..

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#2 Eyesee

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Posted 15 February 2011 - 06:59 PM

Do you think that there might be a chance that it is the monitor instead?

If at all possible, try the monitor on another system for testing purposes.
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#3 highrider

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Posted 15 February 2011 - 07:42 PM

Yes I have tried the monitor with other computers and it works fine..

I have stumbled upon another advice which may be the cause of all this: PSU - I'd be grateful if you could comment on that;

Turns out that my PSU does not meet the minimum requirements for my card (8600 GTS)
Silverpower SP-400p1b has 18A Amperage output on the +12 volts rail while 8600 GTS requires between 22-30A (changes from source to source so Im not exactly sure of the value but it is definitely above my PSU's specs) on the +12 volts rail. However considering that I have been using this card for about 2 months, do you think that this shortage may be the cause of this fail?

#4 the_patriot11

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Posted 15 February 2011 - 07:58 PM

if I have the right PSU, you have the proper amperage, in theory, you need 22-30 amps total over the +12v rails, and that PSU has 2 +12v rails at 18 amps each making it 36 amps total, however, being a cheap 400 watt, and just barely meeting the requirements, its possible your card combined with all your other hardware is tasking it-keep in mind, with cheaper PSUs, the 400 watts is how high it will go when it frys-so if you hit 400 watts, it will fry. So the possibility, may be the PSU, do you have another older, perhaps PCI card you can test in it and see if it solves the problem? You can also test the PSU itself following below listed instructions.

When a computer begins the boot process the motherboard initiates the start up of the PSU. Because of this it is difficult to determine whether the problem is with the motherboard or the PSU when a computer shows no signs of starting up. The purpose of the procedure is to determine if the problem is with the motherboard or the PSU. For safety purposes please follow the instructions step by step.

This test is for ATX PSUs. Some manufacturers use non-ATX PSUs with 20/24 pin connectors that do not have the same pinout as a ATX PSU.

Caution:
This procedure will involve working with live 12VDC electrical potentials which if handled improperly may lead to electrical shock. Proper precautions should also be taken to prevent electrostatic discharges (ESDs) within the case of the computer. For safety purposes please follow the instructions step by step.

First, shutdown your computer. Then unplug the power cable going into your computer.

Once you have opened the case, touch the metal of the case to discharge any static electricity.

The connector of the PSU which connects to the motherboard is readily recognizable by the number of wires in the bundle. To disconnect it you will need to press on the plastic clip to disengage it and then pull the connector up and away from the motherboard. Please take notice of the location of the locking tab and the notch on the socket of the motherboard, this will only connect one way as it is keyed. This wire bundle will have a memory of the way it has been installed and will want to bend back that direction, you may have to play around with it to find a position that the connector will stay in the same position while you run the test.

Posted Image
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From the top left to right the pins are 13-24, the bottom from left to right are 1-12.


Please notice that there are PSUs with 24 pin and 20 pin connectors, the location of the green wire in the 24 pin connector is #16, and the green wire in the 20 pin connector is #14. If you look at the connector with socket side facing you and the clip on the top the number one pin will be on the bottom left corner. This makes the pin out for the 24 pin connector from left to right 13-24 on top, and 1-12 on the bottom. The pin out for the 20 pin connector from left to right is 11-20 on top , and 1-10 on the bottom. If you look at the connectors you notice that these are sockets that fit over the pins on the motherboard where the PSU cable attaches, this is where you will place the jumper. For a jumper you will need a piece of solid wire about the size of a paper clip (20-22 awg), preferably a wire with insulation. It will need to be large enough to fit firmly into the socket so that it will not need to be held in place while testing. You are at risk of electrical shock if you are holding the jumper when you power up the PSU. Insert one end of the jumper into the socket of the Green wire, and insert the other end into the socket of any Black wire.

Once the jumper is in place plug the cord back in. If the PSU is working properly the case fans, optical drives, hdds, and LEDs should power up and remain on. I would suggest that you not leave this connected any longer than is necessary for safety purposes.

To reconnect the 20/4 pin connector unplug the power cord, remove the jumper, and reconnect the connector. Take a moment at this time to make sure that nothing has been dislodged inside the case.

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Primary system: Motherboard: ASUS M4A89GTD PRO/USB3, Processor: AMD Phenom II x4 945, Memory: 16 gigs of Patriot G2 DDR3 1600, Video: AMD Sapphire Nitro R9 380, Storage: 1 WD 500 gig HD, 1 Hitachi 500 gig HD, and Power supply: Coolermaster 750 watt, OS: Windows 10 64 bit. 

Media Center: Motherboard: Gigabyte mp61p-S3, Processor: AMD Athlon 64 x2 6000+, Memory: 6 gigs Patriot DDR2 800, Video: Gigabyte GeForce GT730, Storage: 500 gig Hitachi, PSU: Seasonic M1211 620W full modular, OS: Windows 10.

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#5 dc3

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Posted 15 February 2011 - 09:08 PM

One of the disappointing specifications of this PSU is a 71% efficiency rating. Even with a combined 36A rating of the 12V rail it is questionable how long it can sustain that current rating.

There is a more comprehensive way to test the PSU's out put. This will require at 12V DC voltage meter.


Reading PSU Rail Voltages

Caution: Please read this before continuing.


· Since it will be necessary for your computer to be on during this procedure, you need to be aware that you will be working with live 12Volt DC potentials, which if handled improperly may lead to electrical shock.

· There are electronics inside the case that are very susceptible to electrostatic discharges. To protect your computer, touch the metal of the case to discharge yourself of any electrostatic charges before touching any of the components inside.

· If you are not comfortable doing this procedure, then I would suggest that you not use this tutorial. The risks involved are minimal, but are there nevertheless. Anyone who uses this tutorial will be doing so at their own risk.


There are two devices commonly used to read the rail voltages: a PSU tester, and a multimeter.

The PSU tester is the easiest to use since all that is necessary is to plug the different connectors into the tester and read the results on the LCD display. The problem with most of these is that they only perform a pass/fail test. They will not provide you with actual voltage readings.

There are a variety of multiple meters, but this tutorial will address Analog and Digital multimeters. The advantage of these meters is that you will be able to obtain accurate real time voltage readings.

For those of you who wish to know more about multimeters there is an excellent article in Wikipedia.


Analog Multimeter

Posted Image


An Analog multimeter is a little more complicated to use. Both Analog and Digital multimeters need to be set to the appropriate voltage, but with an Analog multimeter, you will need to choose the voltage range and must read the proper scale.

The Analog multimeter uses a needle display which moves from 0 across the scale until it reaches the voltage being tested. This multimeter has five major linear divisions with multiple scales to read a variety of ranges. An example would be three different ranges. The first is graduated in increments of 0 through 5, the second, 0 through 10, and the third, 0 through 25. Each of these ranges are subdivided into divisions that are graduated into tenths. In order to read 12 volts the 0 through 25 range would be the appropriate one.

Because DC voltage has positive and negative potentials this device is polar sensitive, this means that if you reverse the two probes when reading a positive DC voltage it will read as a negative voltage. This is actually necessary to read negative DC voltages. The two probes are differentiated by their color, Black (negative), and Red (positive). To read a positive DC voltage, the correct probes must be used with their corresponding potentials (positive to positive and negative to negative).

With the probes being used normally to read a negative DC voltage, the needle moves from the 0 to the left, "pegging" the needle. By reversing the probes you can properly read the negative voltages.

Digital Multimeter

Posted Image


The Digital multimeter (DMM) is much simpler to use. As was mentioned previously, you will need to set the appropriate voltage. One of the advantages is that the DMM has an LCD display with a numeric readout, so there are not any multiple scales to read. Another advantage is that most DMMs are autoranging when reading voltages, which means that you will not need to set the range with these DMMs. A DMM will read both positive and negative DC voltages and display them correctly. When reading a negative voltage, a minus sign will appear on the display before the numeric value. This still is a polar sensitive device, so you will still need to use the positive and negative probes with their corresponding potentials.

There are five different DC rail voltages which are color coded. The Black wires are always negative.

Yellow +12VDC

Blue -12VDC

Red +5VDC

White -5VDC

Orange +3.3VDC


There are only three voltages that can be measured easily without disconnecting the 20/24 pin connector from the motherboard: +12V, +5V, and +3.3V.

The +12V and +5V voltages can be read from a four pin Molex power connector.

Four pin Molex power connector

Posted Image


The same voltages can be taken from a four pin SATA power connector, but in order to read the +3.3V you will need to read this from a five pin SATA power connector as seen below.

Five pin SATA power connector.

Posted Image

To read these voltages you will need to insert the Black (-) probe into any of the black sockets, and insert the Red (+) probe in the different colored voltage sockets. To read the voltages from a SATA power connector it is easiest to insert the probes into the bac k of the connector where the wires enter. Unfortunately the sockets of the modular SATA power connectors are not accessible from the back, so the readings will need to be made from the socket side. Some probes are going to be too large to fit in these sockets, so you may need to insert a piece of wire into the socket of which you want to read the voltage of and place the probe on this for your reading. To reduce the potential of creating a short I would suggest taking the ground potential from another connector so that the two wires will remain physically separated.

Caution: It is very important to make sure that you don't allow the two probes to touch each other when taking the voltage readings. This will cause a short which could damage the PSU or other components.

To get accurate readings of the rail voltages it is important that there be a load on the PSU. In order to do this I would suggest downloading Prime95 for this purpose. This program was designed to be used by overclockers to put a full load on the RAM and CPU to determine the stability of their overclocking. Because of this it will put stress on the CPU and RAM which will create higher than normal temperatures. For this reason I would suggest not running this program any longer than is necessary. I would also suggest that an inspection be made of the interior of the case to make sure that there isn’t an accumulation of dust which would impede adequate cooling. Pay special attention to the heat sink and fan assembly on the CPU. If there is a dedicated graphics card with a fan installed on it, look at this fan as well.


Readings should not have variances larger than +/- five percent.

Maximum.........Minimum
12.6V.................11.4V
5.25V.................4.75V
3.47V.................3.14V

Edited by dc3, 15 February 2011 - 09:09 PM.

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#6 highrider

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Posted 16 February 2011 - 07:02 AM

@the_partiot11: Thanks for the info, I will try the technique to see if the PSU failed or not. But I did not understand 1 thing here; I need to connect the green wire to one of the black ones with a jumper, however since the jumper is still in place while plugging it to the motherboard socket, it most likely wont fit?

@dc3: Yes, unfortunately the PSU is not good. Thank you for the reply, but in your explanation it says I have to load the PSU to get accurate readings however I cant do that since the computer doesnt respond.

I believe the error is caused by a bad PSU or a failed PCI-e slot. Is there any way I can test the PCI-e slot for defects?

#7 dc3

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Posted 16 February 2011 - 10:01 AM

When you press the power button on the front of the computer it shorts two pins on the motherboard which in turn shorts the green wire to ground (the black wire) in the 24 pin connector of the PSU. The purpose of pulling the 24 pin connector off of the motherboard is to by pass the motherboard entirely. Once you have placed the jumper between the green wire and any black wire you do notreattach the connector to the motherboard. If the PSU turns on and produces power you will know that the problem it with the motherboard if it hasn't been turning of while attached to the motherboard.

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