Auxiliary/TMPIN2 temperature too high?

Discussion in 'Tyan' started by danielffford, Jan 10, 2013.

  1. danielffford

    danielffford Guest

    I have a Tyan S5101 Trinity i875P motherboard (yeah, I know it's old, but it's been working well till recently!). I run Windows 2000 Pro SP4, though I don't think that's very relevant to my problem.

    In recent weeks it has started rebooting at random times, especially in hotweather (it's summer now in Australia). The CPU and chassis fans are all running. I've cleaned and re-applied heatsink compound to the CPU heatsink, which brought its temperature down a few degrees, but the reboots still occur.

    SiSoftware's Sandra Lite reports 'Auxiliary temperature' as about 72C (CPUID's Hardware Monitor calls it TMPIN2). All the other temps are below about62C, including the CPU.

    My question is, what is this Auxiliary/TMPIN2 temperature? Could it cause reboots at the >70C level? How can I lower this temp?

    Any help would be much appreciated, as I'm not ready to retire this beast just yet. :)
    danielffford, Jan 10, 2013
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  2. danielffford

    Paul Guest

    This is from the user manual.

    Note: The onboard Winbond 83627HF hardware monitoring ASIC automatically
    detects the system, motherboard and CPU temperature. It detects the
    CPU and chassis fan speeds in RPM. The hardware monitor ASIC also
    detects the voltage output through the voltage regulators.

    That implies three sensors. One could be CPU diode. I can't really be sure
    how to interpret the others. On some motherboards, there can be a thermistor
    placed to detect case air temperature. The chips (875P/ICH5 family), I
    don't see a thermal diode listed for those.

    On my 875P motherboard by another manufacturer, only two of the three
    sensor channels are used. The third is placed on an optional two pin
    header, so you can connect your own sensor. It suggests that *something*
    on the motherboard can have a "free" sensor, which they can connect up.
    I just haven't figured out yet, what that free one could be. So when
    they say "system, motherboard", I suspect one of them is part of some
    chip, and the other one involves paying for a thermistor or transistor
    (whichever is cheaper).


    Also, rather than concentrate on the temperature reading,
    I'd be inspecting the tops of the capacitors for leakage.
    There are a total of around eleven capacitors in the upper
    right hand corner of this photo. They're part of VCore
    for the CPU. If the stamped "K" on the top breaks open,
    and fluid leaks out, the VCore voltage can become unstable,
    and random reboots or crashes result. (Of the eleven, four
    could be in the +12V input side, and the other seven run at
    VCore voltage. They put seven in parallel, to withstand
    VCore ripple current.)

    There are other caps on the motherboard, so you should
    really inspect them all. Sometimes, its a cap near
    the video card slot that is oozing, and then the
    video card seems to be unstable.

    While it would be fun to trace down the sensor, there
    are other things you can be looking at, for evidence
    it's in need of repair. Boards can be "re-capped", if
    you spot leaking or bulging caps. It's just time consuming
    work with a soldering iron and vacuum desoldering station.
    (Caps can be very hard to get out, even with good equipment.
    It all depends on "hole diameter" versus "lead diameter",
    as to how hard it is. My first employer used generous
    hole sizes, and the caps would almost fall out. Not many
    companies will design them to work that easily.)


    One other thing. Your Northbridge uses the "four hook,
    one spring wire" retention scheme. The problem with that
    is, the hooks soldered into the motherboard, are typically
    made of the wrong materials. They use something that looks
    a lot like stainless steel, which does not solder well.
    It should have been a fat copper wire with tin/lead on the outside.

    The solder joint on the bottom of the board, which holds
    the four hooks, is a "cold joint", and then, the hook easily
    pulls out of the motherboard. When that happens, the
    Northbridge heatsink can fall off. Inspect the blue colored
    heatsink with the word "Tyan" printed on it. It won't be
    completely motionless. Even if the spring is still secure,
    you may be able to rotate the heatsink a few degrees. If they
    used thermal tape between heatsink and chip, it might remain
    stuck in place. In any case, if a Northbridge overheats,
    that would be the reason - a hook pulls out.

    On some Dell, the hooks are actually checked by a motherboard
    circuit. They run a continuity check through the hooks. So a
    small amount of current flows through the spring wire that
    holds the heatsink. If a hook lets go, the circuit is broken
    and... the motherboard won't start. The user is expected to
    figure that out for themselves, that the hook has let go.
    Now, the interesting thing about that, is the design engineer
    *knows* those hooks are made of the wrong material, and put
    a sensing circuit in place, waiting for the inevitable. And on
    hearing about the approach, all I could think is "how stupid is
    it, to know the mechanical details aren't secure, and put in
    an electrical feature to check for it". I'd much sooner use another
    kind of retainer. Push-pins aren't very nice, but they're
    another solution to mechanically securing the thing.

    Fortunately, the ICH5/ICH5R runs cool enough, it doesn't
    need a heatsink. Your ICH5 family Southbridge never had
    a heatsink, and should never get more than warm to the touch.
    That's the square just above the two blue IDE connectors
    in the photo.

    Paul, Jan 10, 2013
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  3. danielffford


    Dec 12, 2014
    Likes Received:

    Many thanks for your considered reply. I had a look at the motherboard's caps, and sure enough a couple of them are bulging!

    Problem is, because of the location of the board and the caps on it, I can't read their values and voltage ratings (even with an inspection mirror) without removing the board from the case. Given the number of add-in boards and cables on the board, I dodn't really want to remove the board just to read the cap values, then refit it, then take it out a second time (and refit it again) after I receive the caps!

    Do you know anywhere where I can find the values and voltage ratings of the main power supply caps on this motherboard, so I can order them in advance of taking the board out for repairs?

    DanielF, Dec 12, 2014
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