No. I could get other fans to connect to the headers... just don't have any spare 4pin...
I have taken this PSU out and hooked it up to my scope and ran it under load - voltages look great, noise well under control. It is a new Corsair TX750v2. I've also tested another PSU in the system and it did the same thing. I've also logged the output of "ipmitool sensor" every few seconds and logged hi-lo for voltages over a couple days - they are all well in spec.
I just checked the fail headers. First the Power Fail: 0v. The Overheat / Fan Fail... 3.16v. The manual says flashing is fan, solid is overheat... so it's likely the BIOS thinks the machine is overheating?
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The alarm has been currently going off for over 24 hours now (one of the longest ones). Just as a test I reset the BMC using the web interface, and the beeping continued. The previous "failed" fans now show the "N/A" they used to again. The beeping is likely caused by a BIOS routine.
I'm seriously considering disassembling the BIOS and finding the routine for these beeps and nop'ing them out. There is no reason for a machine that is 31c ambient under load, with no malfunctions whatsoever, to be beeping like this. As SuperMicro doesn't care, what other choice do I have? (ACTUALLY, reading the manual, I missed something: jumping pins 3 and 4 of the speaker header will ENABLE the onboard speaker, which is the default. I've removed this jumper. Not ideal (as other beeps won't come through) but good enough for now...)
coretemp-isa-0000
Adapter: ISA adapter
Core 0: +23.0 C (high = +83.0 C, crit = +99.0 C)
Core 1: +22.0 C (high = +83.0 C, crit = +99.0 C)
Core 2: +28.0 C (high = +83.0 C, crit = +99.0 C)
Core 3: +21.0 C (high = +83.0 C, crit = +99.0 C)
w83627dhg-isa-0a10
Adapter: ISA adapter
Vcore: +0.85 V (min = +0.60 V, max = +1.49 V)
in1: +1.85 V (min = +1.62 V, max = +1.99 V)
AVCC: +3.31 V (min = +2.98 V, max = +3.63 V)
+3.3V: +3.31 V (min = +2.98 V, max = +3.63 V)
in4: +1.54 V (min = +0.00 V, max = +1.65 V)
in5: +1.26 V (min = +1.13 V, max = +0.30 V) ALARM
in6: +1.46 V (min = +1.42 V, max = +0.00 V) ALARM
3VSB: +3.28 V (min = +2.98 V, max = +3.63 V)
Vbat: +3.12 V (min = +2.70 V, max = +3.30 V)
fan1: 0 RPM (min = 10546 RPM, div = 128) ALARM
fan2: 2136 RPM (min = 0 RPM, div = ALARM
fan3: 0 RPM (min = 10546 RPM, div = 128) ALARM
fan4: 0 RPM (min = 753 RPM, div = 128) ALARM
fan5: 0 RPM (min = 10546 RPM, div = 128) ALARM
temp1: +30.0 C (high = +60.0 C, hyst = +55.0 C) sensor = thermistor
temp2: +28.5 C (high = +81.0 C, hyst = +0.0 C) ALARM sensor = thermistor
temp3: +26.0 C (high = +0.0 C, hyst = +70.0 C) sensor = thermistor
cpu0_vid: +1.300 V
System Temp | 26.000 | degrees C | ok | -9.000 | -7.000 | -5.000 | 75.000 | 77.000 | 79.000
CPU Temp | 0x0 | discrete | 0x0000| na | na | na | na | na | na
FAN 1 | 2065.000 | RPM | ok | 215.000 | 400.000 | 585.000 | 29260.000 | 29815.000 | 30370.000
FAN 2 | na | RPM | na | na | na | na | na | na | na
FAN 3 | na | RPM | na | na | na | na | na | na | na
FAN 4 | na | RPM | na | na | na | na | na | na | na
FAN 5 | na | RPM | na | na | na | na | na | na | na
CPU Vcore | 0.848 | Volts | ok | 0.640 | 0.664 | 0.688 | 1.344 | 1.408 | 1.472
+3.3VCC | 3.312 | Volts | ok | 2.816 | 2.880 | 2.944 | 3.584 | 3.648 | 3.712
+12 V | 12.243 | Volts | ok | 10.494 | 10.600 | 10.706 | 13.091 | 13.197 | 13.303
CPU DIMM | 1.544 | Volts | ok | 1.152 | 1.216 | 1.280 | 1.760 | 1.776 | 1.792
+5 V | 5.056 | Volts | ok | 4.096 | 4.320 | 4.576 | 5.344 | 5.600 | 5.632
-12 V | -12.098 | Volts | ok | -13.844 | -13.650 | -13.456 | -10.934 | -10.740 | -10.546
VBAT | 3.120 | Volts | ok | 2.816 | 2.880 | 2.944 | 3.584 | 3.648 | 3.712
+3.3VSB | 3.280 | Volts | ok | 2.816 | 2.880 | 2.944 | 3.584 | 3.648 | 3.712
AVCC | 3.312 | Volts | ok | 2.816 | 2.880 | 2.944 | 3.584 | 3.648 | 3.712
Chassis Intru | 0x0 | discrete | 0x0000| na | na | na | na | na | na
PS Status | 0x1 | discrete | 0x01ff| na | na | na | na | na | na