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Front panel display? How does it sense???

By direcTVguy ยท 14 replies
Mar 30, 2006
  1. I am not new to building PC's but i have always kept it simple. Cheapest case, cheapest mobo, etc..

    I am building one now for a co-worker who picked out his own case cuz he's in love with the idea of the LED display for temp and stuff.

    I'm going through all the connectors but have yet to figure out how the display recieves that data from (the mobo im assuming).


    i only have 2 connectors not yet connected. one of them is a cluster of single pins, tbp/tba + and -. vcc, ground. im assuming these have something to do with the front panel 1394 and therefore do not care about them.

    but there is another 3 pin male connector labeled "cpu fan' coming from the front panel that i cannot find a home for. i have the cpu fan properly connected to the male receptacle on the mobo. but what is the one from the front panel for? and is there a home for it?

    my case is Broadway Com Corp model 824hl and my mobo is Biostar M7VIG400.

    Any answers or help would be greatly appreciated!!

    i am also kale_from_mn on yahoo messenger if you want to IM me.
  2. Rik

    Rik Banned Posts: 3,814

    Most front panels that sense temperature do so by a sensor that plugs into it. The sensors are usually 2 pin and black and have a tiny flexi pcb with a sub miniature sensor mounted on the end. You need to place the sensor in the location where you wish the temp to be measured.

    The cpu fan connector is for monitoring the speed of the fan that is mounted on the processor heat sink, the fan is usually connected to the motherboard. A fair few motherboards also monitor the cpu fan so swapping it to the front panel may cause the pc to not start up and bleep instead. If this happens, reconnect the fan to the motherboard, go into the bios ald look for cpu fan detect, if its there, disable it, reconnect the fan to the front panel and all should work fine ( its how my system is set up, i have a coolermaster aerogate3 that speed controls and monitors all my fans).

    Hope that helps,
  3. akaivan

    akaivan TS Maniac Posts: 470

    Usually the mobo has an area for anything the cas has to offer, Usually there labeled like PANEL1. Good luck :bounce:
  4. direcTVguy

    direcTVguy TS Rookie Topic Starter

    that was helpfull yes. havnt found the micro sensor you referred to but am still looking.

    still confused about the front panel connector labeled CPU FAN as i cannot find any spot on the mobo for it. it is 3 prong and about the same size as the power cord for the CPU Fan itself, but male as opposed to female. maybe my mobo is just plain lacking in capabilities?
  5. mailpup

    mailpup TS Special Forces Posts: 7,102   +419

    There seems to be a missing element. Is there a female lead coming from the front panel besides the male lead? What I am getting at is the CPU fan might connect to the male front panel lead and the "missing" female lead connects to the motherboard (CPU fan connector). This way the circuit goes from the motherboard through the front panel to the fan which is how the panel can access the info from the motherboard sensor. One of the three prongs on the motherboard CPU fan connector is for sensor data if you look at the mobo manual.

    I just guessing, however, as I have never hooked up one of these types.
  6. direcTVguy

    direcTVguy TS Rookie Topic Starter

    that would make a great deal of sense it it were streamlined like that, yet i have not found a second lead that would make it work that way. i just moved into a new home and everything is packed for next couple days, will go back to work on it then (had to wait 3 days for my 20 to 24 pin adapter anyway! grrrrr)

    i'll let you know what i found out and thanks again to all who have helped out here
  7. luvhuffer

    luvhuffer TechSpot Paladin Posts: 443

    I don't have a clue about all this except the suggestion to somehow hook the front panel display in line with the mobo CPU connector that mailpup offered. I would want to add one thing though. If one was to disable the CPU fan warning in the BIOS and hook up the HSF directly to the front panel display device, then unless the front panel display has a built in alarm system, one would have to constantly be monitoring the front panel on the chance the fan stopped. The fan warning system complements the thermal shut down settings for the CPU in the BIOS, so make sure the CPU temp shutdown is activated in the BIOS. If you don't trust your readings in the BIOS install a 3rd party software program like motherboard monitor 5. Intel has the TCC (Thermal Control Circuit) that will shut down the Vcore before damage occurs (theoretically) and I'm not sure if AMD has something similar, but I'd hate to let it get that far. Chips fry rather quickly without adequate cooling.
  8. direcTVguy

    direcTVguy TS Rookie Topic Starter

    Alas!!! I have found the probes. Just like you said. 3 of them. They were all neatly bundled together and VERY WELL HIDDEN between the front panel and chasis. Not sure what the "real" technique for place these probes are but i just kind of stuck the CPU one in the CPU heatsink, and the HDD one in the hard drive. Hack work at its finest! But the temps are reading. Skipped the AGP one as i am not using an AGP card.

    Still no clue what to do with the CPU fan 3 prong male adapter. No place for it on the mobo. I know it has something to do with fan control and stuff as the front display has "low, med and high" which is showing "low" all the time right now, and a cyclone symbol labeled "fan" which is never lit up. Im sure there would do their thing if i had that adapter plugged in somewhere. From what ive read from you all so far, i would need to buy a 3rd party fan controller to use this mystery 3 prong. But not caring enough about it at this point.

    Thanks again for all the help!!!
  9. mailpup

    mailpup TS Special Forces Posts: 7,102   +419

    Look closely at that three prong connector. Is it possible it is pass through connector? In other words, you plug it into the mobo connector (where the heatsink fan is connected now) and the heatsink fan connector piggybacks onto it. Thus, you have current going from the mobo through the front panel connector to the fan and that's how the monitor senses fan speed?
  10. Rik

    Rik Banned Posts: 3,814

    The cpu fan connector on the front panel should not be connected to the mobo at all. I use a coolermaster aerogate2 fan speed controller, in its instructions it says that the cpu fan connector is to allow it to monitor the cpu fan instead of the mobo. It very clearly states that connecting it to the mobo cpu fan connector will damage both the front panel and the mobo.
  11. KingCody

    KingCody TS Evangelist Posts: 992   +8

    You don't plug that into the mobo, you plug the CPU fan into it (instead of the mobo... I don't recommend it though, if I were you I would leave the CPU fan plugged into the mobo)

    of corse they do... lol

    pretty much all mobos will shut the system down if the CPU reaches a certain temp (except old or really cheap ones maybe, but I don't know of any). the better boards allow you to select the alarm temp max and the shutdown temp max
  12. direcTVguy

    direcTVguy TS Rookie Topic Starter

    That system was buttoned up and out the door to my co-worker a few days ago. He loves it and for a cheapie it did really fly.

    As for the 3 prong connector i did some research and it was most definitely designed to hook on to a 3rd party fan controller for monitoring, nothing to do with the mobo.

    So basically just about all of you were exactly right which i never doubted.

    I am due to build MYSELF a new system within a couple months here which will be anything BUT low end and cheap so i will see you all then with my barage of questions when i go to shop for components! :)

  13. Rik

    Rik Banned Posts: 3,814

    Glad we could help.


    The 824hl case has 3 temparatue sensors on the end of wire leads which are placed on the gpu ,hdd,an your cpu ! heat resistant tape is an easy way to attach these temperature probs! Just remeber dont get the wires in any fans and do not stick the temperatur prob between the cpu and the cpu hest sink cooling fan! attach the cpu temperature prob as close to the cpu as you can ! Tape the temperature probe in securely !
  15. KingCody

    KingCody TS Evangelist Posts: 992   +8


    where did you dig up this thread from? lol, this issue was solved almost a year ago

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