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Building my first computer

by Comp-phan / April 10, 2007 4:31 AM PDT

After having bought two store stocked systems, I finally decided to try to custom build my own. I got a 400 watt PSU from Ultra, motherboard is a Biostar NF325-A7 ATX ( got it for free with my AMD A64 3400+ cpu from Newegg), a 300 GB Ultra ATA and a 160 GB serial ATA ( both from Seagate), a 256MB AGP 8x video card (from PNY),a 16X double layer DVD recorder ( from Memorex) and 1 GB DDR memory. I was originally using the case from my old system I purchased in 2000( from CTX, horrible customer service never ordered from them again) I gutted the whole unit and replaced everthing but when I turned on the main power switch nothing happend no power or anything. I tested the power unit it checked ok ( it is running my newer computer, a Compaq 5WV280 I bought in 2003 just fine ) I bought a new case , an ULtra UVWizard ATX mid tower case and I followed the diagram from the motherboard manual exactly on how to hook all the componets but I'm still getting the same problem, no power ( the CPU heatsink fan spins for a couple of seconds then nothing ) I'm hoping that anyone who's had experience building their own systems can tell me what I'm doing wrong (or right)

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One way to check is to run the system
by Ray Harinec / April 10, 2007 7:04 AM PDT

outside the case on a larghe peice of carboard. Putting new mobo in old case frequently finds that one of the prior mounting posts no longer line up with the new mobos mounting posts and short out the artwork on the bottom of the mobo.

Another may be that the old mobo didn't require the 4 pin 12 volt connector and thus the power supply doesn't have one.

There are many, that's why it is so important to assemble the system in baby steps and check each function as it gets added.

The first step can be the bare mobo on a table, the power supply on a table and test that the mobo's power turn on logic works. There is no CPU, no memory, nada to run this basic first step.

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How Can you tell if MB is good?
by Comp-phan / May 4, 2007 10:28 PM PDT

I tried as you suggested I put the board on a flat piece of board, took out the CPU and the memory but I did leave the HDD and power LED plugged in. I turned it on but nothing happeded still. I don't know if I should have unplugged it completly but then there would be nothing to tell me if the board was active or not. Is there another way to test to see if power is going into the board?

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I believe that it
by Ray Harinec / May 4, 2007 11:04 PM PDT

was stated that one could tell if the Mobo power control circuit was working was to note that the fan on the power supply was rotating continuously.

How could you still have the HDD and Power LED still plugged in if the mobo is outside the case laying on a board???

If you did that somehow, seems that you could also have plugged the Power Switch wires to the mobo. The first step that was mentioned was to use a screwdriver to momentarily short the two power Switch pins on the mobo, so that the case is not involved.

The two items you listed would be OK IF they are not accidently plugged into the wrong pins OR remember they are both polarity sensitive, if the wires are reversed the LEDs will not illuminate. Try reversing the leads. Having them connected in reverse will not damage the LEDs.

Also most mobos nowadays have a LED on the mobo [sometimes two very close to each other] One lights when the 5 volt standby power is present on the mobo. This happens as long as the power supply is plugged into a live wall outlet, the switch on the PS's rear is in the 1 [ON] position [zero is NOT the ON position!!!! it's boolean 1 = true, 0 = false]

If there is a second LED on the mobo it illuminates when the power supply is fully on. That one MAY require that the 20/24 pin connector AND the 4 pin 12 volt connector be plugged in. The 4 pin 12 volt does not have to be plugged in for the power supply to turn on by MOMENTARILY shorting the two power swx pins on the mobo.

I don't mention color. I'm colorblind and can't tell which is what color. The manual should identify the LEDs on the mobo if they exist.

I hope that the mobo you bought was not a "refurbished". I seriously doubt that a refurbished one has been tested fully.

Now, to simply check the power supply by itself, plugged into the wall outlet only, rear switch on, on the 20/24 pin connector [work from the rear of the connector with a thin wire, paper clip etc,]. short the green wire to any one of the black wires in the same connector. As long as that connection is maintained the power supply should be ON as indicated by its fan rotating [The rear fan only. If it has two fans the other one may require being connected to the mobo for speed control].

The mobo power control simply puts a logic low [gnd] on the pin with the green wire.

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Mobo mounting
by Ray Harinec / May 4, 2007 11:17 PM PDT

Mobo mounting info:

First note that the only mounting holes of interest are those with a gold ring [plated copper] around them. Understand that a mobo is a four layer board. Actually four layers of printed circuit artwork, each layer insulated from the other except where connections are needed. The connections are made by holes drilled through the layers and through the specific circuit leads that need to be connected. The connections are made after assembly of the layers by flow soldering in a solder bath and the solder plates through the holes, thus they are called plated through holes, before plating they are vias [can go from one layer to another VIA the hole].

Back to the mounting holes, one of the inner layers of the mobo is basically a ground plane with most of the ground [returns] wiring. Each of these mounting holes are plated through and connect to the ground plane, they are also continued through to the bottom side of the mobo.

The grounding of interest in this case is that of very high frequency signal and noise, not low frequency such as audio. For audio grounding the old single point grounding is proper. For RF [radio frequency] grounding, one wants to get as to close to an infinite equipotential surface as possible. Simply want the signal and noise level at every point to be electrically as close to every other point as possible [of course we don't achieve that] as good practice.

Thus, for RF/EMI purposes we really want the mobo's ground plane to be RF connected to the mounting plate [thus metal standoffs used]. Again, good RF ground if made by the intimate contact of two mating conductive surfaces, NOT by screws. The sole purpose of the screws is to maintain the intimate contact. Good engineering practice never uses a screw to carry current.

Thus, for the mobo subject, the intimate contact is from the ring around the mounting hole on the bottom of the mobo, the surface of the hex standoff and the other end of the hex standoff to the mounting plate.

Now the kicker [many in the forums will say this is not so, however they are simply not correct] one usually gets what appear to be insulated washers with the mobo. In fact they are insulated, HOWEVER that is not their purpose. Remember that we want intimate contact which means that one wants to tighten the screws. However, the plated rings around the mounting hole are somewhat delicate printed circuit lands, THUS the insulated washer goes under the head of the screw to prevent the tightening of the screw from damaging the printed ring.

Over the years I have seen people in the forums tell people to put the insulating washers between the mobo and the hex standoff. Just think about trying to accomplish that. They simply do not understand the subject of good RF grounding.

Now, many mobos will provide various types of plastic snap in devices. I never use them, however I can see where the mfr's are not going to try to take the time to get people to understand the subject The only penalty for using plastic versus metal is that the overall EMI performance of the system will be lessened. However, there really is no way that will be detected by anyone, thus the easy way out. I have talked to a tech that worked at a mobo mfg plant and he wasn't even aware that the mounting holes are grounded to each other inside the mobo.

BTW Intel has actually gone to 6 layer mobos in a few cases. Basically a layer is a fiberglass type material with copper plated on both sides and then etched for circuitry, thus it is two layers a second such board is then attached to the other through an insulating layer of something called prepreg and then squeezed extremely tightly. Imagine the accuracy needed to have all of the holes line up perfectly. It is really fascinating. When I worked on the Minuteman program we used 14 layer circuit cards. Note, always an even number of layers.

Regardless, If I twere you I would least use the metal mounts at the end of the mobo near the CPU and I/O ports.

The other related issue is that where one puts a new mobo into a case where a mobo existed before. In these cases, since not all mobos use the same mounting hole, it is not unusual for one to leave an old hex mount in at a place where the new mobo doesn't have a mount. This results in shorting out the good circuit artwork on the new mobo. Seen this in the forums a number of times over the years, however the classic was one where the individual mounted the mobo to the mounting plate with no spacers.

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by xFulcrumx / May 6, 2007 10:25 PM PDT

you say the cpu heat sink fan spins for a few seconds then nothing?

well then you are getting power.

1) a cheap psu like Ultra is bound to cause problems regardless of what people say...1 of the most important components in your computer and you buy a cheapie?.. thats the fist problem and problally the main say you used it to run your new comuter?so you know the psu isnt the problem...even though I wouldnt use a cheapie.

2)did you check if the main power connector is 23 or 24 pin? most new
PSU's will come with the adaptor. If you dont have the adaptor, buy one at newegg - like 5$ or less.

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The momentary start is virtually always [to Comp-phan]
by Ray Harinec / May 7, 2007 9:21 AM PDT
In reply to: ??

an indication of something drawing too much current from the Power Supply, such that the Powwer supply's overcurrent protection circuit shuts the supply down to protect the supply.

Unfortunately, such failure could be in the supply itself, such as a defective over current circuit or defective regulator with too high a voltage that causes the overvoltage protection to fire shutting the supply down. Of course the overvoltage circuit itself could be bad.

Then there is the possibility that a hardware item is defective. I mentioned how to mount a mobo in the event it was mounted improperly and some of its artwork was shorted.

If this momentary on happens on a table with no CPU, memory, or anything else, obviously it is either the power supply or a mobo component. No practical way to repair a mobo component.

Also mentioned the mounting instructions because we actually had a first time builder, many moons ago, mount the mobo directly to the mounting plate. Lo and Behold, it acted like yours.

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Finally made some progress
by Comp-phan / May 22, 2007 6:04 PM PDT

Good news and some bad news. I finally was able to figure out my motherboards power problem. I was hooking up both the 20 pin power connection and that extra 4 pin additional power connector when I only needed to attach just the 20( If the motherboard has both the 20 pin and the 4 pin power connectors, how do you know when to hook up both and when not to?). The problem now is that the standoffs I got with my new case are raising the MB too high in the case so that when I plug in the video card I can't screw it down to the back plane. It sticks up about 1/4 to 3/8 inch above is there a different type of standoff I can use?

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Need a lot of clarification regarding
by Ray Harinec / May 26, 2007 11:24 PM PDT

the 20 pin and additional 4 pin. Please clarify; first lets talk about the main power connector on the mobo, is that a 20 pin or a 24 pin??? From the power supply to mate with the mobo connector, is that one of the newer type that can be either 20 or 24 pin, by simply having an extra four pin connector that can be attached to the 20 pin to make a one piece 24 pin connector.

OR are you talking about a totally separate four pin connector, usually located near the CPU. That connector is used to provide power to the regulators on the mobo that power the CPU. If the mobo has a socket for such, then it MUST be used to power the CPU.

Re the 12 volt 4 pin. The mobo determines what powers the regulators for the CPU. It is NOT the choice of the CPU. Older mobos powered the CPU's differently.

Prior to the addition of the 12 volt 4 pin connector the CPU's regulators on the mobo were powered either from 3.3 volts or 5 volts. Eventually as the power consumed by the CPU grew, the current pulled at such a low voltage caused too much drop in the wiring and could even burn up the printed lands on the mobo. Funny, then because as the voltage used by the CPU went lower and lower but the power went up, the current required to provide suffient power =E x I went up. Solution was to raise the source voltage, the current goes down proportionally and then allow the onboard switching regulators to reduce the voltage again, but with very short leads to the CPU itself, thus the voltage drop problem is ameliorated.

I have no idea what 4 pin connector you were having trouble with.

If you are using the standard hex standoffs for the mobo, then you need a low profile video card, they came out just because of the problem that you are having.

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by toolbox20 / June 2, 2007 10:57 AM PDT

really have enjoyed reading your comments on motherboards, their composition, etc. Really informative.
I've been contemplating building my own system for a while now. I'll be in Afghanistan for a year, but when I get back (god willing) I'm going to make the plunge - even if its a pain in the rear, I know it'll be educational.
Keeping in mind that in a year everything will have shifted to the next level, if you had to do it today, what type of core set-up (MOBO, PSU, CPU) would YOU pick if you were going to do the job?
Just curious...

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New Build
by Urkel. / June 3, 2007 3:09 AM PDT
In reply to: Ray...

If I was starting a new build, I'd use the following:

Gigabyte GA-P965-DQ6 Motherboard. I like the new P35 boards but DDR3 is still really expensive, when you can even find it, and not much faster then DDR2. Give it a year or two before that upgrade.
Antec 650watt PSU. More power never hurts.
Intel C2D. Dual cores and fast as hell. As for Qusd-core, I'll wait for the prices to drop a bit more and for games and apps that take advantage of the design.

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by toolbox20 / June 3, 2007 9:04 AM PDT
In reply to: New Build

...thanks for the input!
When DO you think the prices on quad-core CPU's are liable to drop? Rather, would it be worth waiting an extra year to get a quad, or is that so far off its just better to go ahead and get a robust dual-core?

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Certainly praying for your safe return.
by Ray Harinec / June 4, 2007 1:15 AM PDT
In reply to: Ray...

When you do get ready to research what one to build, start a new thread. The technology is moving ahead at lightspeed ever since Intel dumped the P4 and the Conroe core was developed. By the time you return, the penryn cores [updated conroes on 45 NM cores] as duals or quads.

The Conroe core allowed Intel to finally outperform the AMD's for gaming etc. AMD is working feverishly to make a come back. Their attempt at the comeback should come out in a few months. Then the real need for valid research will exist. Both AMD and Intel will tell us how great their CPU's are. Independent evaluation will sorely be needed.

At that time a short period of research by reading various aricles regarding what is available at the time will be required in order to make a good decision.

Basically all aspects of all the technology of the computer and its supporting elements are undergoing dramatic changes, Chipsets, location of the Memory controller Hub, memory type, power supply connectors, drive ports on mobos, {example, newer Intel's, no longer provide PATA ports], Temperature/heat generation considerations of each component, Video cards will still be advancing every two months or so.

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by toolbox20 / June 4, 2007 9:49 AM PDT

...will-do. I guess any vetting of future components at this point would just be idle speculation.
Thanks for the relevant information - and the kind words in your title! Even though we've still got a month before mob, prayers and thoughts NEVER go unappreciated.

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Re cards (AGP) sitting too high to screw in...
by VAPCMD / June 3, 2007 3:56 AM PDT

Are you mounting the MB directly on top of the raised 'bumps' on of the MB tray..or adding the stand-offs on top of the raised 'bumps'? (see link below). Without having the rig in front of's possible you SHOULDN'T be using the stand-offs on top of the raised 'bumps'...only use the stand off where the MB holes don't line up with the raised 'bumps' on the MB tray.


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Yes, that is the case I am using
by Comp-phan / July 17, 2007 8:44 AM PDT

so what type of standoff should I be using ? Are there one that are half height?

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Check the case instructions . . . if you have the case
by VAPCMD / July 17, 2007 11:55 AM PDT

pictured at the link, it looks like you don't need (shouldn't use) any stand-offs at all. The 'bumps' are like the brass stand offs and raise the motherboard off the motherboard tray. Thus the motherboard will sit lower allowing peripherals (video cards) to be full seated and tightened in place.

Let us know


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A Heartfelt Thank you
by Comp-phan / November 9, 2007 1:39 PM PST

Just wanted to let you all know I got my self built system up and running perfectly( more or less) thank you all for your advice!!

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You're welcome and Thanks for the feedback.
by VAPCMD / November 9, 2007 9:21 PM PST
In reply to: A Heartfelt Thank you

It's always good to hear 'the end of the story'.


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