Ooops. No power-up after build

[tekbro]

Greetings.
I've built a simple, basic system from parts I had lying around. A while back I purchased a DFI AZ-30-TC (YES, I know it's ancient! lol). Never really had a use for it, until my usual PC caught a virus (shame on me).

So after reformatting the primary dos partition and and several un-successful attempts to install windows 98 (it kept hanging on the "Insert diskette in drive b:" error), I found an old system with win98 already installed.

I decided to try and run a new system off this other 98 HD, using my old HD in slave mode. While I was at it, I remembered I had this DFI board that hadn't even been out of the static bag. I also bought this Athlon XP 2600+ Thorobred off this local guy on MySpace. I'll admit, the CPU looked a little cruddy. There was thermal paste all over the top of the CPU. But I decided to give it ago anyways.

Anyway, I get this thing together. I'm using a case from a system I purchased back in 1998, with a Pentium II 400 MHz, so I'm guessing that I got the front panel connections right. The power supply is a rarely used 300 Watt Antec, so it's not junk. The case & PSU were used successfully with a different mobo/CPU in the past.

So here's the system specs

Athlon XP 2600+ Thorobred
DFI AZ30-TL with on-board LAN, Rev. A Set at default FSB of 100 MHz
WD 13 GB HDD (MS)
MAXTOR 120 GB HDD (SL)
Antec 300 W PSU
Apacer DDR 256MB, PC2300

So I power it up- I plug it in with the PSU switch in the OFF position. Then I switch the PSU switch to ON. The CPU fan starts...and then just stops. The PSU doesn't run. No LEDs come on. It just sits there. So I turn the switch off, and then I hear the faint chirp noise from the power supply, like capacitor discharging.

I made sure all my cards were seated, and all my wires were connected. Everything looks ok. The ONLY thing I can figure is the CPU. The CPU fan lead is plugged into the fan power on the board.

At THIS point, rather than risk messing up my only other respectable CPU in my possession by testing it in the new mobo, I'm tempted to just purchase a new system. Any other troubleshooting suggestions before I hop on to newegg.com?

 

[madmurph]

That sounds like a dead PSU. Did you try another? Is there a four-pin connnector on the MB, near the CPU? Is it connected to the PSU?

 

[tekbro]

Hmmmm....
I'm not sure. I don't think you're talking about the main ATX power connector. The only other thing is the CPU fan power connector. Sorry if I'm still shaking off the cobwebs...it's been a while since I built a system from "the ground up" like this. so I may be missing some simple things.

As far as the PSU being bad, that seems so unlikely, because I bought it brand new, and I only used it for a few months before putting together my current system (the one that I got the virus on). It was working perfectly before.

 

[madmurph]

I think with most MB's that support Athlon, there is a square, 4-pin female connector, on the MB near the CPU socket. The PSU has a corresponding plug. This supplies power to the CPU, not the CPU fan, and if they're not connected, the system won't boot. It still sounds like PSU. See if you can borrow one.

 

[tekbro]

I checked out my DFI AZ-30 TL motherboard again. Maybe I'm blind or unobservant, but I can't for the life of me find a connector on the mobo that matches that 4-pin plug coming out of the power supply. So I'm thinking my board doesn't use it. Maybe newer boards do, but this board is kinda vintage, so maybe it just doesn't use it.

At this point I'm out of ideas. Like I said, the cpu FAN spins up, but I don't even think the PSU fan comes on. I have to agree with you off the top madmurph that the PSU seems like the culprit. I will see if I can wrangle up a working spare and try it...

Thanks!

P.S. What do you think about the board shorting out from the underside touching the bottom of the case/chassis? The board is much smaller than the old one I had in this enclosure, (ATX vs. micro ATX), so I didn't put in the extra standoffs this time...

 

[madmurph]

What do you think about the board shorting out from the underside touching the bottom of the case/chassis?

pull the MB and make sure there isn't a stand-off under there, where there is no hole. Some boards put 4 holes across the back of the MB, some put only 3. Also, have you pulled the CPU out of the socket and checked for bent pins?

 

[blunc]

I suggest assembling the mobo outside of the case to eliminate the possibility of shorting to the case or standoffs. In most cases the power supply will shut itself off if the mobo is shorted or if it doesn't receive the "power good" signal back from the mobo.

 

[AdamBomb42]

Unplug the drives and try again.

 

[tekbro]

Well... here's an update (like anybody cares :lol: )

I stripped a PSU from another case I had lying around the room, comparable power rating.

Same thing. Now I know this is B/S! :x No WAY I have two bad PSUs. So I go get my outlet tester. Sho nuf, I got an open ground in my outlet. Bingo! Not quite: I have another very stable system that has worked just fine literally for years off that same outlet, so the open ground is not toasting the PSU's (though I know that's no good-i'll fix it later).

Back to the story. The two PSUs I happened to test both had those switches built in. Not all of the PSU's I've dealt with have had these. So I tried something different. Normally, I have the PSU switch in the OPEN (off) position. This time, I left it in the CLOSED(on) position and then plugged the cord into the PSU. Pushed the ATX Power switch. System started normally.

Now, I tried this in the other, original system I was building, and I did the same thing. Fortunately, I also discovered that I made a slight error in connecting my front panel leads to the mobo. Since I made both changes at the same time, I'm not sure which was the trick, but the system starts now.

The downside: I wasted you guys' time when I should've figured this out on my own (I apologize). The upside: At least I don't have a bad PSU! Thanks for your help and advice.

 

[madmurph]

Some of us care, as each experience adds to the collective consciousness. Thanks for the update; glad you figured it out. (BTW, I try to keep track of all the posts in which I have participated for just that reason.)