powerfailure: how comes PC beeps just before?

[VJ]

Hello,

Perhaps a weird question. I know experienced the 4th power failure (whole cityblock!) in about the same number of weeks.

This time, just before everything failed, the lights dimmed and flickered. The weird thing is: my PC beeped during this period (I heard 3 or 4 beeps before everything went dead).

Just curious: where do the beeps come from?

The mainboard is a SuperMicro X5DA8 (dual Xeon), powersupply is a PC Power and Cooling 510XE; the bios is configured to remain off in the event of a power failure (so the beeps aren't caused by attempts to boot!) and I have no UPS installed (but am seriously considering one now).


Jörg

[schmosef]

Sounds like your motherboard is sensing drastically out of spec current/voltage in the moments before the blackout.

[VJ]

It seems the most logical explanation, even though I couldn't find any reference to this feature/behaviour.

If so, then the voltage must have been seriously out of spec: the PSU has the following operating range: 90-264 VAC, 47-63Hz (normal here is 240 V, 50 Hz).


Jörg

[Taz]

...I have no UPS installed (but am seriously considering one now).

I would, considering the cost of the parts your using

[VJ]

I would, considering the cost of the parts your using

FWIW, I already have a serious surge protector...

But after the previous power failure, I had to reinstall my windows (I suspect some system files were corrupt).



Jörg

[schmosef]

The price for a basic UPS has gone down considerably. I'm selling current model APCs for about $150. The same spec and features would have cost around $300+ a few years ago.

[dbdg]

I've got an APC 2200 and for life of me have not been able to get hold of the main power cable for it.

(Given the unit from the back of a lorry)

[VJ]

The price for a basic UPS has gone down considerably. I'm selling current model APCs for about $150. The same spec and features would have cost around $300+ a few years ago.

True...
Calculating the one I'd need for my system always brings me to the high-end range (1000+ VA), which commonly also yields long working times (80 minutes or so). However, I'd be satisfied with just 5 minutes or so (enough to have the system make a clean shutdown).

Still, I'll shop around, as 4 powerfailures in almost the same number of weeks is too much to be good (3 of the lasted over 2 hours, the last one just a tad over 1 hour). And any additional minutes that it works is fine, might prevent me from even having to shut down at all.


Jörg

[Umfriend]

And enable you to continue crunching at all times, which is *important*.

[schmosef]

LOL!

Was installing the crunching client on all company PCs (I'm not even sure what you guys are crunching these days) part of your outrageous demands for that new job?

[Umfriend]

I did think about it, but no. So you are joining us? That'd be really really great. Although some are crunching Seti, folding and Einstein or something, we do best ATM at CPDN. It'd be soooo nice to have more crunchers there.

Sorry VJ, we'll return OT with the next post I think.

[xortam]

Be really careful with your devices during those brownouts as they can seriously damage electrical motors (fans and such). I hadn't had my laser printer protected for many years and I was told by the repair shop that line voltage fluctuations were probably the cause of the failed fuser.

[az]

Pure speculation, but maybe during the power failure there is a lot of ripple in the kilohertz range, and your PSU's transformer is vibrating at that frequency. I have in my internship worked on some special audio amps which had transformers to decouple the output from the electronics (and transform the voltage for PA in.house installations). This device produced on power on a test tone with the outputs switched off, but you could faintly hear it from the transformer.

Are you sure it's not coming from the PC speaker?

AZ

[xortam]

They used to listen for infinite code loops in the early days of electronic computers. You could tune an AM radio to pick up signals from these old computers and you could recognize the repeated tones that indicated the program was executing an infinite loop.

[SpiralDragon]

one of the "percs" of living in lebanon is that the first thing you have to buy befor you buy a computer is a good UPS.... and befor you buy that you need to buy a voltage regulator..... oh and foget about grounding.. non existant....