Power Supply Issues

[dsp]

Hi all,

I seem to have a somewhat nagging problem, which doesn't affect me a whole lot but still bugs me.

My Processor (as is in the sig) does not want to POST with a higher multiplier, even though previously it had worked perfectly for months at 9*100. It however runs perfectly with a lower multiplier (5.5).

Also maybe the same theme, my USB ports stop working at various times and it requires a reboot to get them working again. This is viewed by watching my WingMan Rumblepad's LED's turn off at different times usually after at least 2 hours of running but sometimes for 4 or more hours.

Any help would be greatly appreciated. Thanks in advance.

dsp

[Greebe]

Have you added any new hardware to your system lately? What i'm driving at is it's possibly that the system is either being loaded down and thus causing additional ripple, that by dropping the cpu clock down puts it back into spec.

Age/quality and available power of the PS can also effect this

[dsp]

Greebe,

For the CPU when it stopped working at 900 (a while ago now) I think I had just added a hard drive (maxtor 40GB). With the USB it started (i think) since I installed the Win-TV or the new 256MB stick of RAM.

As an addition to my previous post, I can boot succesfully at 900 (9*100) if I power the computer off and while its spinning down turn it back on again, and then its perfectly stable as long as I don't do a hard reset.

The PS is as old as my CPU (about 6 months or so) and the PS is made by "Topower"(No name I guess).

dsp

[Greebe]

Wombat requested that I post this for him...

USB ports are a known issue with Abit boards

And your no-booting, I had the same problem. For a split second on an AMD boot, the processor controls voltage and multiplier according to its bridges. After a little bit of booting, the BIOS takes over.

My system wouldn't boot b/c I had a 133MHz FSB on a Duron 850. I penciled the mult to 7, and the voltage to 1.95V (I think), and my processor boots every time. The BIOS actually lowers the voltage, and ups the FSB ratio some.

[dsp]

Thanks Wombat,

But I have a question about the no boot. As you say the processor takes care of multiplier and voltage for a split second before the BIOS, wouldn't my CPU still boot as it would initially boot at 6*5*100 1.65V and then the BIOS would change the multiplier to 9X and voltage to 1.8xVolts?

Thanks for the USB answer, like I said, its slightly annoying but livable.

dsp

[birdy]

i had a similar problem with my athlon thunderbird. It would only boot if the entire system was discharged, ie i would have to unplug it from the wall and try to switch it on while disconnected to get rid of any stored charge. Then it would boot again. It turned out that the connections on the L2 bridges (the ole pencil trick) had started to degrade, once i had re-done them the problem disappeared (or if i ran at the default multiplier in the bios).

[dsp]

Birdy,

Wouldn't it then not work if I changed the multiplier at all? I am considering that it may be the pencil trick is degrading but the fact that it works perfectly at 5.5 or even 6 is odd and seems to point elsewhere.

Thanks for that point though.

dsp

[Wombat]

Now that I can post, a few follow ups.

1) I don't know how the BIOS is written. It may be that the multiplier is upped before the voltage. They probably aren't done simultaneously.

2) If adding another HD really did cause the problem, I wouldn't be surprised. Your PS may not like to ramp up for the system boot. And the power consumption of your CPU is linear w.r.t. frequency. It may be that somewhere between 600 and 900 MHz you cross a power limitation from the PS, or indirectly from MB issues. In which case, I think that upping the voltage like I suggested may help. Here's (loosely) why:

1: CPU can operate fine with voltage V and power P. Anything less and it will stall out.

2: PS provides voltage V and power P to a CPU that is off.

3: CPU comes on, as does everything else. PS feels the strain, and its supply to the CPU dips so that you're not getting V (or P) anymore.

So if you set the voltage higher, this dip doesn't hit the CPU as hard, and you can make it through. (This explanation would probably all fall to crap if you tell me you have a PCP&C PS though. Those are awesome).

[birdy]

I don't know about going lower with the multiplier. Perhaps the bridges were only cut to prevent higher multipliers (a more likely overclock with the earlier 100mhz board than upping the fsb)
I could try out my theory but that would mean turning the machine off for a bit, I can't do that

[dsp]

Here's a little update.

Even when I try to boot at 700(7*100) it will not work, 700 works with a voltage (in the BIOS) of 1.6 or in reality 1.65+/-.01 (using boot, then turn off, then quickly turn on again). It seems odd that the 700 seems to be affected by a power spike where the 650 at the same voltage doesn't where they both will work with a voltage of 1.65(1.69). The computer does however work at 700(6.5*108) perfectly.

It still seems to be the pencil wearing off but then how could I lower the multiplier?

Thanks for your replies so far Wombat and Birdy.

dsp

[birdy]

It's time to get your pencil out mate

[Wombat]

Yeah, time to redo the pencil.

And while you're at it, try to get a good old wooden pencil, HB lead or softer.

Mechanical pencil leads are graphite suspended in a large amount of polymer. One lead gave me spotty connections, and another gave me no connection at all.

Connect those L7 bridges while you're at it

[birdy]

oo - what have i missed?

What/where are the L7 bridges and what happens when you join em?

[Wombat]

L7 bridges are the ones that control the default voltage.

Here:

http://www.a1-electronics.co.uk/AMD_Section/CPUs/TBirdDuron_overclocking.html

[dsp]

Wombat/Birdy,

Thanks again, I was hoping that it wouldn't be something expensive (Power Supply). I don't think I'll redo the bridges quite yet (yes originally it was done with a mechanical pencil) as I might sell this processor and the FOP-38 is not an easy on/off heatsink.

On a somewhat similar topic, which should I upgrade to (first):
A Kyro II (Hercules w/TV out) $185 (can)
or a 1GHz T-Bird (200FSB) $144(can)?

This is from my stated specs at the begining of this topic. Thanks for the replies.

dsp