Onyx Heat Bed runs cold

[lightninjay]

Thanks for asking Carl! Indeed she is. I cut up an old dead motherboard I had to get at the ATX socket it had on it. I found the pins the green and a black connect to and soldered two wires over to W.I.S.P.E.R.'s power switch. After doing that, I modified a PCI-E cable that came with the modular power supply that had 3 +12v leads and 3 ground leads. I hooked those up to the RAMBo inputs and she's up and W.I.S.P.E.R.I.N.g again!

[Eaglezsoar]

Thanks for asking Carl! Indeed she is. I cut up an old dead motherboard I had to get at the ATX socket it had on it. I found the pins the green and a black connect to and soldered two wires over to W.I.S.P.E.R.'s power switch. After doing that, I modified a PCI-E cable that came with the modular power supply that had 3 +12v leads and 3 ground leads. I hooked those up to the RAMBo inputs and she's up and W.I.S.P.E.R.I.N.g again!

Great Deal! I am glad that you got it up and running again!
Very imaginative to use the connectors the way you did, you should not have any power supply issues in the future.
A job well done.

[RegB]

Tangent alert;;
I was watching a print yesterday and got to thinking that MOST of the bed probably runs cool as soon as a print starts.

Mine starts out at 90C, but soon after filament gets laid down at about 220C right over the thermistor the bed heat shuts down for a while.
I think the part being printed continues to insulate the thermistor and possibly passes some heat down to it.
Not sure that it matters, unless one prints sequentially, i.e. goes to another (cooler) area on the bed while the thermistor is being kept warm by the first part that was printed in the middle.

[lightninjay]

Just to clear things up, the high readings I was getting were actually due to my auto-ranging meter. I wasn't paying close enough attention and those high values when the rail was under load, attached to the bed, were readings in milliVolts, not Volts.