Mach I: System crashes as soon run temp is reached

[donny_paycheck]

As the title says, I'm running a 3.0C on a Mach I. For testing purposes, I've isolated the Prommy from the PC by using a second, dummy power supply to turn on the Prommy, then turning on the PC when it's down to temperature.

My problem is, I can start the Prommy up and turn the PC on when it's in cool-down, and everything is fine. I go into CMOS and watch the CPU temperature and evap temp both drop as the compressor does its work. All seems fine.

However, the instant the evap temp hits -33C and the fans click down to low speed, the PC resets and won't even POST again. I turn it off (leaving the Prommy running) and turn it back on. No dice. I try a multitude of other options, including running the PSU from its own source rather than passing through the Prommy. Still no joy.

There is simply no way I can even get my system to POST below -33C when the fans click to low speed. And if it's already booted by that time, it hard crashes. Does anybody have ANY idea what could be causing this? Like I said, I've tried every method I know of it isolate the fault and I can't, so I'm at the end of my rope here. Any insight would be appreciated.

[rhino56]

do you think it might be the way the MB is reading the cpu temps?
i know my Mb can only read right down to like -36 or something.
it sounds like something like that, try to disable the cpu temp in the bios, im not sure what board you have but it could be that once it goes below what is readable its posting as +256C or so and wont boot up for its own safety features.
worth a try i guess.

[donny_paycheck]

That's a good idea. However, I already tried that, but forgot to mention it in my frustration. Just to add though, even if it was mobo temps causing it, they wouldn't shut it down EXACTLY when the fans slow down EVERY time. The tolerance is just too broad for that kind of consistency.

Thanks for the reply though.

[sneakyfart]

i read a post somewhere about a similar problem to yours and the fix was manually setting the fan speeds so they run full speed all the time.

[chilly1]

If you install a 10K Variable resistor and a switch you can set it so the fans stay on and when you need to see the temperature open the switch. The switch shorts the temp probe and the VR in in series with the temp probe. The switch shorts between the VR and the probe to the other line.. As soo as XT gets back up I have schematics there.

[rhino56]

i guess i dont get it, i have my promey hooked up independent from my comp really, the fan speed couldnt really have any effect on my comp, the only thing i plugged in is the power for the promey, the 2 other plugs i didnt plug in. works fine, so im not sure how you have yours hooked up but i think if it were hooked up like mine the fan speed would have nothing to do with the comp itself.
the only thing touching my comp from the promey is the cooling head itself on my cpu. the rest is independent.

[donny_paycheck]

^^ Exactly. What could possibly be causing this? The ONLY connection between my Prommy and the PC is the cooling head itself. That's not even an electrical connection. There is no conceivable way I can see this effect even being possible, and I am utterly stumped.

Originally posted by chilly1
If you install a 10K Variable resistor and a switch you can set it so the fans stay on and when you need to see the temperature open the switch. The switch shorts the temp probe and the VR in in series with the temp probe. The switch shorts between the VR and the probe to the other line.. As soo as XT gets back up I have schematics there.
Awesome, yeah I'd like to see those. I was going to post this at XS but it was down yesterday. Not the most elegant solution, but it'll have to work. Do you know why this happens when something so seemingly unrelated as the fan speed changes?

[Tomsawyer]

Ok at the risk of sounding like a jackass I will toss my 2 cents in.

When you say the system crashes the instant the fans click off what does the prommy do? Is it still running or does it it seem to restart also?

Have you tried adjusting the "start" tempature and see if the problem duplicates at a higher or lower temp? Check the manual, you should be able to open that front panel and tinker.

Are the power supplies you are using high end or generic knock offs like Tiger? I doubt its some sort of powerfeedback but when the fans slow down could that extra juice somehow going to reset signal?

As has been stated I would also ask around on www.xtremesystems.org also, perhaps bowman or the dude or crash could have a better solution than my poor skills

[rhino56]

are you using a 6 strip or is the promey plugged into the wall?
do you have any software running on startup that can disable your comp? i know web temp can be set to disable if temps get too high, i dont know about others though.
i would try putting the comp on a different circuit all together from the promey
do this by shutting off a circuit in the fuse panel until you find the one the promey is on, then find one thats still on. plug the comp into one and the promey into another.
its sounds like a juice spike thats causing problems for your psu though.

[donny_paycheck]

Originally posted by Tomsawyer
When you say the system crashes the instant the fans click off what does the prommy do? Is it still running or does it it seem to restart also?
It stays running with the fans on low speed.

Have you tried adjusting the "start" tempature and see if the problem duplicates at a higher or lower temp? Check the manual, you should be able to open that front panel and tinker.
I'm about to try this. I'll post back with the results.

Are the power supplies you are using high end or generic knock offs like Tiger? I doubt its some sort of powerfeedback but when the fans slow down could that extra juice somehow going to reset signal?
It's a PC Power & Cooling Turbo Cool 510 with PFC. The PSU I'm closing the Prommy relay with is a 250w Antec, but it's not powering anything otherwise.

As has been stated I would also ask around on www.xtremesystems.org also, perhaps bowman or the dude or crash could have a better solution than my poor skills
They were down yesterday but I'm posting this there today too just to see.

Here: http://www.xtremesystems.org/showthread.php?s=&threadid=32246

Originally posted by rhino56
are you using a 6 strip or is the promey plugged into the wall?
do you have any software running on startup that can disable your comp? i know web temp can be set to disable if temps get too high, i dont know about others though.
i would try putting the comp on a different circuit all together from the promey
do this by shutting off a circuit in the fuse panel until you find the one the promey is on, then find one thats still on. plug the comp into one and the promey into another.
its sounds like a juice spike thats causing problems for your psu though.
Both the Prommy and PC are plugged into an APC Smart Ups 1400. Nothing's set to kill the power on CPU overtemp; I made sure that stuff is disabled. As far as a power spike caused by the Prommy switching from high to low speed, I was thinking this too at first. The thing is that even if I let it get down to temp and switch to low speed before powering on the PC, it still won't POST. Also the UPS is very sensitive to power fluctuations and would normally alarm if anything was that severe.

[Stee]

sorry if you already said but have you tried powering them without the apc in the loop?

[rhino56]

what MB are you using?

[donny_paycheck]

^^ Abit IC7

You guys aren't going to believe this. Somehow, the St1 and St2 signals became reversed in the chip controller. Yeah, I've messed with it before, but didn't think anything of it because that was some time ago. In other words, instead of holding in reset while in cool-down, it was allowing the PC to boot. Then when operating temp was achieved, it started holding the reset high.

So I reprogrammed the chip controller to have St1 high until -33C (reverse mode) and then drop it, raising St2. No problems now, it's running great.

The only thing I can think of that happened was that it was running like this beforehand and I didn't notice because the gray reset wire had fallen off the motherboard header, and wasn't doing anything. I probably messed up the settings a while back and didn't realize the full implications of my stupidity until just now.

It's always those little things that get me too. Thanks for all the help though, I really appreciate it.

ps. nice OC rhino, what stepping is your chip? I've got a SL6WG 3.2 here that I might switch with my 3.0 SL6WK.

[rhino56]

i knew it had to be something overlooked, thats always the problem with me also, the problem is me. im not sure what the stepping is as im in AR right now but ill check this week when i return.
i can get 4.25 prime 95 stable at 1.65 volts with it though.

[rhino56]

it is a sl792

[donny_paycheck]

Originally posted by rhino56
it is a sl792
FWIW I have this SL6WK @ 4.05ghz, 1.625v right now. Might try my 3.2 in the future but I kinda doubt it. I'm thinking of putting it in the classifieds here.