I recently switched-off the graphical boot on my computer and watched the scrolling commentary. One of the things I caught was a complaint that no sensors were available. I then ran sensors-detect and it eventually reported success, and the complaint no longer occurs. But ...

I've just run the command sensors and the result was weird:

w83697hf-isa-0290
Adapter: ISA adapter
VCore: +1.58 V (min = +1.22 V, max = +0.08 V) ALARM
+3.3V: +3.10 V (min = +2.11 V, max = +0.58 V) ALARM
+5V: +4.65 V (min = +4.30 V, max = +3.44 V) ALARM
+12V: +11.25 V (min = +1.82 V, max = +0.24 V) ALARM
-12V: +0.55 V (min = -9.65 V, max = -14.83 V) ALARM
-5V: +1.89 V (min = +1.33 V, max = -4.49 V) ALARM
V5SB: +5.30 V (min = +0.11 V, max = +0.86 V) ALARM
VBat: +3.28 V (min = +0.06 V, max = +0.00 V) ALARM
fan2: 3308 RPM (min = 3515 RPM, div = 8) ALARM
temp1: +33.0°C (high = +4.0°C, hyst = -116.0°C) ALARM sensor = thermistor
temp2: +43.0°C (high = +120.0°C, hyst = +120.0°C) sensor = thermistor
beep_enable:enabled

The configuration file or something must be wrong here, with the max and min figures! Although the result is that all but one of the measurements are flagged ALARM, I haven't have any alarms or warnings pop up. Since the system has been running happily for 5 years (I hope that's not a case of speaking too soon!) I presume I actually have nothing to worry about. Looking at the /etc/sensors3.conf tells me more than I really want to know or can readily understand.

Can I just forget about this? Or will having the sensors active eventually cause some system to panic, in which case is there some way I can switch them off again?

I'm out of date on V Core specs, so no comment. I would not think 1.58V is fatal to anything. First problem would be heat.

+3.3V: +3.10 V (min = +2.11 V, max = +0.58 V) ALARM
+5V: +4.65 V (min = +4.30 V, max = +3.44 V) ALARM
+12V: +11.25 V (min = +1.82 V, max = +0.24 V) ALARM
12V: +0.55 V (min = -9.65 V, max = -14.83 V) ALARM

These are alarming.3.1V is very borderline for the 3.3V. 4.65V is _out_of_spec_ for the 5V. 11.25 is low for the 12V, but you'll get away with that. But -12V at +0.55V means the supply is missing. You're just lucky nothing uses that.

Guess: Something has died in the power supply, and it is pumping current to ground, reducing all supplies.
Next Guess: Power Supply is overloaded.
Last guess: The plug on the motherboard is overheating, and you're losing power there.

Replace the power supply.

Further googling revealed
http://www.neoseeker.com/Articles/Ha...voltages/3.htm
All five motherboards tested had sensors under-reporting voltages. Figures reported (as opposed to actual voltages) included
+3.3V: 3.15
+5V: 4.57
+12V: 11.55
suggesting my figures may not be too far off.
The standard core voltage for the AMD Athlon is 1.6, so my 1.58 is fine.

The moral here seems to be that the output of sensors needs to be taken with a pinch of salt.

You missed the most important thing - Your -12V @ +0.55V is blown.

Your conclusion about sensors may well be wrong. Your power supplies are low. A 5V supply coming out of the box at 5.000V will drop on the leads across to the m/b, drop over the plug, and drop even more on the m/b where the power tracks can be thin. Sensors measure at the end of the line (=lowest point), but you can only get a meter on high points.


Once power goes below 4.8V it is out of spec, and chips are not guaranteed to function. At 4.6 - 4.5V many start misbehaving. Ignore it if you like - I don't care, but don't tell people it's OK because newbies might get the wrong idea.

Point taken, but the situation is complex. I've just checked the BIOS, and I can read a few of the sensors from there. This claims 4.8V on the 5V output! This, and the test I quoted, does suggest that lm_sensors may be unreliable. Moreover, the notes in /etc/sensors3.conf are hardly reassuring: "The math is convoluted, so we hope that your motherboard uses the recommended resistor values."

I'm surprised that so little information seems to be available on this matter, at least via Google. There are innumerable posts on how to get lm_sensors working, but next to nothing on how to make use of the results.

Cough Cough.

I have made use of them for you :-P