better way to do it change resistor.

If you use it will not reboot

Dont forget sudo before shutdown commands.

sudo shutdown -h now   --should work.

And if you do do that make sure to pick a resistor with the proper "temperature coefficient" - that is how the resistor value changes with temperature (which is pretty much what you've discovered here, although in your case there is an apparent "aging" of the pencil mod too - the carbon trace that you've added probably oxidizes and becomes more or less conductive).

We are a couple days yet from getting our 16 chip boards with the trimmer on the board.  I have some 8 chip boards that are an experimental OC board that use the same trim pot and I want to set the stage for how this will work.

In order to use this trimmer, you *must* have a multimeter and know how to measure resistance.  If you don't know what I'm talking about, you aren't ready to try to OC your boards.

An easy place to take resistance measurements is to get ground off the M-board GND terminal (where you would connect direct 12V cables - the terminal screws).  The red probe would go on the top metal contact of the Pulse inductor, which is the large bulky component on the H-card.  Be sure not to also touch the caps that are nearby or you won't get a correct voltage.

While measuring the voltage, use your super-micro tweaker phillips screwdriver to *slowly* turn the trimmer clockwise for higher voltage or counter-clockwise for lower.  The trimmer has an effective range of about 180-degrees.  If you turn it down too far, you will see voltage begin to rise again. 

Don't make voltage changes quickly.  If you go higher than about .895v you better know what you are doing or you will kill your chips.  I don't even know what voltages people are getting away with on these boards.  Find a guide or post before you start mucking around.  Overclocking *will* reduce the reliability of the boards.

nice to see you guys selling 8 chips boards. FYI, for the one I made (https://bt.irlbtc.com/view/228677.msg3259455#msg3259455), I'm running around 0.9v and pulling 21-22GH and ~23W. been too lazy to try higher voltage.

If we don't have a multimeter or plain just don't know what we're doing, are we better off just getting gen 1 boards?  Does the trimmer have a zero stop so we don't accidentally plug the board in with the trimmer cranked up from shipping and handling?

I'm loving the gen 1 boards that arrived today (thanks for the quick shipping!).  They're hashing above 30GH/s with no OC.  I might be happier just filling up my old M board rather than working with a new starter kit.

FTFY

We certainly don't want to connect an ohmmeter in that way!

Will you be selling any 8-chip boards? It'd be nice to eliminate the voltage regulator bottleneck on overclocking.

At what voltage would the chips be ruined if not actually mining and producing heat, such as with the chainminer process shut down? Is .895v where it just gets too hot, or where stuff starts shorting internally?

noone has been running bitfury chips more than a few months, so its unknown