Power LED connector

[In_Athens]

I have the netvista 6568 in a non IBM case. The problem is that when i disconnect the ATX power and reconnected again, it doesn't start up with the power button, but only if I short the Wake On Lan pins. After this, it goes fine!!! When I shut it down under WinXP, it shuts normally and then I can start it using the power button, with no problem at all. Unless I disconnect the ATX power and there it goes all over again. Any help?

[BGreeNZ]

I don't think I've had any problems with the NetVista 6568 motherboard I transplanted.  However, I have a similar problem with another (shop-built) system.  After reconnecting mains to the ATX power supply, pressing the power button once does not power up the system.  If I press it a second time, the system will power up.

If this does not solve your problem, perhaps you could try connecting the power switch to the alternative pair of pins, and see if this makes a difference.  If you try this, please post back with your results, as this should help to determine what, if any, the difference is between the two pairs of "power switch" pins

[In_Athens]

Pressing the power button many times didn't worked out for me. But look what i found: If i first connect the ATX power to the motherboard and then give power to the PSU, the funs work for 3-4 seconds, then they stop and then i can start the mobo pressing the power button. If i disconnect the ATX power from the mobo while the PSU is on power - but the machine shutted down from the windows - and then recconect it again, i can't start the mobo pressing the power button. I have to short the Wake On Lan pins. It looks like X-Files. And something else. I couldn't find any difference between the two pairs of "power switch" pins.

[BGreeNZ]

So, are you saying that you are physically disconnecting the PSU from the motherboard, with the PSU still connected to mains power?  That is not advisable because, as you probably know, the ATX power supply provides a constant supply of +5V standby power to the motherboard, to implement functions such as soft-on or wake-on-LAN etc.

An ATX motherboard relies on this clean, continuous +5V standby power in order to perform a power-on-reset of its logic (different from the reset that happens when you press the power or reset button).  This means that if you connect a live PSU to the motherboard, the electrical noise introduced could prevent the motherboard from resetting reliably, leaving it in an unknown state.  What you should do is switch off (or unplug) the PSU before connecting it to an ATX motherboard.

As for the fans and lights coming on for a few seconds when mains power is applied, this is normal behavior for an IBM system, and all 3 of mine (2 NetVistas and a 35A) do this.

[Ron G]

See my reply at http://www.xtremecomputing.co.uk/forum/showthread.php?t=4521

For your convenience, I have decided to duplicate my post below:

I had this exact same problem. Fortunately, I had another NetVista, so I reverse-engineered the 8-pin connector on that. Here's what I came up with (IBM NetVista 6568-LCA motherboard):

,--------,
|12345678|
'--,__,--'

Pin Colour Description
1   Black  HDD LED (Gnd)
2   Yellow HDD LED (+ve)
3   Green  Power LED (+ve)
4   Black  Power LED (Gnd)
5   Yellow Power Switch (Pair 1)
6   Black  Power Switch (Pair 1)
7   Black  Power Switch (Pair 2)
8   Yellow Power Switch (Pair 2)

The motherboard does not seem to care which pair of pins are used for the power button (I tried both), so I don't know why IBM chose to use 4 wires.
Unfortunately, this pinout requires that the 3-pin connector for the power LED be split into two 1-pin connectors. Same deal for the 4-pin speaker connector. (This goes onto a little white 2-pin connector near the back of the motherboard)

Thanks for sharing the results of your efforts with us,now I need to get brave and try it.LOL
I measured the voltages on the pins and have concluded that pins 5/6 and 7/8 are good candidates for power on/off and/or reset but in practice they both do the same thing,once you break the circuit to either set the power goes off so I am still looking for a reset connection.
I will give the voltages that I got here for comparison.

         OFF                                      ON
Pin 1=0V                                Pin 1=3.9V
Pin 2=0V                                Pin 2=5.1V
Pin 3=0V                                Pin 3=3.3V
Pin 4=0V                                Pin 4=0V
Pin 5=3.2V                             Pin 5=3.3V
Pin 6=0V                                Pin 6=0V
Pin 7=0V                                Pin 7=0V
Pin 8=3.2V                             Pin 8=3.3V

The question I am asking myself is should there be any signal on both pins of my harddrive LED or just one pin?
There will be a voltage differential of approximately 1.2 Volts between the pins but is that what the LED will be looking for?
As I mentioned in my original post this particular motherboard (a 6578-KAU) appears to be an orphan in that the documentation that IBM is publishing does not reflect the motherboard that I have here.
This board has a 20 pin connector that is referenced on a very few same vintage other PIII boards from IBM but they nowhere have or can find the pinout of the connector.It is referenced as the front panel connector and that is all.
I have talked at length with Allen from India and Calvin from Atlanta about this and all they can give me is an apology.The board is made by Intel but Intel has nothing in their site to compare it to.
The chipset is the D815E and there are a gazillion D815 boards out there,I have at least 4 myself and several more under my care.None of them have this connector.
I have some LED's plugged into this 20 pin header (it looks identical to an IDE header,same keyway and everything) which I am going to remove and resample the voltages on the 8 pin connector to see if they might change which would answer some of my questions possibly.The FRU number on this board is 09K9982 which of course is one of many for this model motherboard.
I also have an 6579 desktop here at home that I can take out of service to take some measurements if I have to but hate to resort to that as it very likely will be different as well although IBM says they are the same.Thanks for your indulgence,if I find anything to add I will post it.Ron G

[BGreeNZ]

Thanks for sharing the results of your efforts with us,now I need to get brave and try it.LOL

I measured the voltages on the pins and have concluded that pins 5/6 and 7/8 are good candidates for power on/off and/or reset but in practice they both do the same thing,once you break the circuit to either set the power goes off so I am still looking for a reset connection.

The above pinout was derived directly from the front-panel wiring of my NetVista 6578-PBA original case.  I'd be very surprised if it didn't work.

Good luck trying to find a reset switch.  Like most (all?) brand-name not-quite-standard computers, the front-panel does not feature a reset button

[Ron G]

I connected everything according to your pinout and it does indeed work as you predicted.I don't own anything new enough to to know about the no reset button but I am not going to look any longer.The reset button will also power the computer off and on so that is close enough.LOL
I am retired but I have worked on this thing for about a week and need to move on with my life:))
Normally I will not connect any device to a source that I am not sure of and getting a voltage reading on both pins of a solid state device or junction without documentation to back it up raises a flag and I exercize caution as was the case here.
I must say that too much information can also be a hindrence and I reasoned that since noone else had posted anything to the contrary in the absence of any voltage readings and since this was a ten dollar motherboard and my time is still worth something I went ahead and connected it according to your diagram and everything works just fine,thanks.
The 20 pin connector has nothing connected to it but what little I can find on it calls it a front panel connector.
The 8 pin connector is labled an LED connector.
I will say that the first two pins of the 20 pin connector counting left to right and top to bottom will not only boot the computer but also resets the cmos so after changing the cmos battery to a known good one with no change I started searching for a different control source.
Thanks for your replies and the hard work you did to clear this up and again,for taking the time to share it with us.Ron G

[coolj2009]

Hello, 

    This is the IBM FRU25P5090 (IBM NetVista 6794) motherboard for Front Panel pinouts...   On this motherboard is the exactly how it suppose to look when looking at the motherboard in front of you..   Enjoy!!