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veniculum
05-09-2005, 10:06 AM
Hi all...new member. I just got my hands on a couple of older motherboards/cpu's and have decided to build complete systems, that I plan on selling eventually (for cheap of course)
Anyway, I'm not sure what make the boards are, but I know that they are AMD Athalon 650 CPUs. The one board had a bad bios, so I pulled the cmos chip out of the other one and put it in the first, and it seems to be fine. So now I'm down to one board...oh well...got them for next to nothing.
The problem I am having (now that I have built the system completely, and installed the O/S) is that when I first power up the system, the fans start, and a series of a few beeps (I forgot what code that is..think it's video) but that's it. It's only after I press reset that I get video and the drives start to spin up and the computer loads up to the O/S without issue. I've never seen anything like this. I've verified that all connections to the mobo are correct, and all the bios settings seem to be ok. I've also tried various video cards and memory and the same thing happens no matter what. It's certainly not a big deal as the system runs fine once I press reset..it's just one of those annoying things that rubs my OCD the wrong way.
Any suggestions would be really appreciated.
Thanks!

Todd

wuppo
05-09-2005, 12:46 PM
Will the video start first time if you disconnect the drives power? Some older power supplies, if heavily loaded, struggle with the initial power on surge and exhibit the "requires reset to boot" symptoms. Whilst power supplies provide a "power good" signal, the motherboard doesn't have to take notice of it, and perhaps your mobo is trying to initialise before the voltages are OK. If so, the cure is a replacement [ bigger ] power supply.

Graham L
05-09-2005, 03:49 PM
" Whilst power supplies provide a "power good" signal, the motherboard doesn't have to take notice of it, "

Wrong. Motherboards have to take notice of it. The PG signal is tied to the CPU reset pin. The CPU is held in reset until PG goes high. Only then does it vector to the POST in the BIOS code.

Some power supplies have a cheap PG circuit, which does not test for all the important supplies being within tolerance.

If fans are starting, the 12V must be coming up. But even an overload on 12V shouldn't stop 5V (and 3.3V) from coming up. The "cheap" PG is often just fed from the 5V supply. 5V is regulated; 12V is normally just set by the different number of turns on its winding.

If all the connectors are OK (no broken, missing, or bent pins or sockets) try another power supply.

pctek
05-09-2005, 04:09 PM
Don't want to be rude but what are you doing building PCs that you are going to sell to someone if you don't know what you are doing?
You "forgot" the beep code? You can look them up on the net...
You don't know what make they are? It would have a model number on the board - you can look that up too.
You took the CMOS chip out of one and put it in the other - welll, I hope the boards are the same model.

wuppo
05-09-2005, 05:00 PM
"
Wrong. Motherboards have to take notice of it. The PG signal is tied to the CPU reset pin. The CPU is held in reset until PG goes high. Only then does it vector to the POST in the BIOS code.

Bollicks - probably taken straight from a google.

I have had motherboards that don't use the Power OK signal (I believe the mobo developed it's own pwr good signal). I have also dealt with dodgy power supplies that won't start a PC without using the reset key; and reducing the load on the power supply allowed the system to start up from a power on.

Graham L
05-09-2005, 06:08 PM
"Bollicks - probably taken straight from a google." Is that meant to be a compliment? The Internet, as mediated by Google is a wonderful resource (if the simply wrong misinformation is filtered out).

"bollicks" on Google doesn't look very useful, as one would expect of those who can't spell "balls". However, "bollocks" (www.thebollocks.com/) looks like an interesting site, though that, too, is not very useful for power supply information.

A PC motherboard which doesn't use a Power Good signal won't work. There may be some boards which generate their own PG signal; but since the power supplies are required (by the At and ATX standards) to produce Power Good, and the chips to generate your own signal would cost something, cost-conscious motherboard manufacturers will use the PSU signal. So I don't think there will be many which don't.

I agree there are "dodgy" power supplies, as well as faulty ones. I said as much.

bartsdadhomer
05-09-2005, 06:44 PM
One of my machines here does exactly the same
Tried all sorts of video, memory, hdd, psu swaps etc nothing fixes it
One of the capacitors on the board has a smallish bulge on top so I'm putting it down to that
One day I'll get round to fitting a new one then I'll know for sure

veniculum
06-09-2005, 03:57 PM
Don't want to be rude but what are you doing building PCs that you are going to sell to someone if you don't know what you are doing?
You "forgot" the beep code? You can look them up on the net...
You don't know what make they are? It would have a model number on the board - you can look that up too.
You took the CMOS chip out of one and put it in the other - welll, I hope the boards are the same model.

Don't want to be rude??? You don't know me or my level of skill. I'd say you telling me that I don't know what I'm doing was pretty rude...I know very well what I'm doing..I've been doing it for a very long time, and if I was planning on building something for myself or something that was actually worth more than the 20 bucks I expect to get for this thing at my garage sale this week, then I might invest more time in researching the exact beep code (as it's only in about 20 different books on the shelf across the room from where I'm sitting right now) and motherboard model numbers. (and yes, they are the same exact model...guess how I know that???...there's a little thing on the back thats called a sticker...it has the model number...wow..that was tough) For right now, I just wanted a couple of quick suggestions because I don't plan on investing much time on this old thing. Isn't that what these forums are for. Oh yeah...I forgot why I typically don't go to forums for help/info. Because there's always a know it all who, instead of just trying to be helpful, has to make a judgement call based on a short, informal, undetailed question. Thanks for your help man! I would've never known that I could go online or open a book and find out what the exact beep code was...or what model my board was..

To all the others who have replied and mentioned power supplies, I was leaning towards the same thing...so I tried 3 different 400 watt power supplies with the same results. One supply was complete junk, but the others were quality pieces, so I'm pretty much convinced that it's not that.

The bottom line is, I don't really care if I have to press reset to get the machine to work...as long as it works after. This is just one of those things that will frustrate me because I couldn't find a fix quickly...quickly being the key word...as I would like to just sell the thing as soon as possible and move onto something else.