Ibanez SD9 Always on?

[jimosity]

Anybody have details on modifying an SD9 for 'always on'?

[Mark Hammer]

Do you want to EVER be able to turn it off, or are you simply looking to have it waken in the "on" position any time you power up?

[jimosity]

Never turn off.

[alexradium]

the simplest way would be bypassing the effect output fet and removing the bypass fet,this way you'll have it always working,if you want the led lighting that's another story

[Mark Hammer]

That's easy, then.  There will be two FETs on the board that are used to turn it on/off.  One will be in the path of the effect signal, and the other will be in the path of the bypass signal.  Both are 2SK30AY types (likely say "K30" on the package).  When either one is turned "on" the drain-source resistance goes very low.  But it can't go any lower than a piece of wire joining the drain and source pins.

So, find those transistors, and identify the pin that has a diode connecting to it.  The schematic found here will show you what other parts connect to those FETs: http://www.diystompboxes.com/smfforum/index.php?topic=33632.0

Once you have the right one flagged, simply join the two pads that DON'T connect to the diode with a piece of wire.  You can either unsolder the other one, or simply unsolder one end of the diode connecting to it to disable it.

That's it.  Your SD9 will now be in "on" mode for good...or for evil, depending on how you set it and use it.  

[jimosity]

Hmm...when I jump the two pins, I can hear the effect; but also the bypass signal at the same time...

[Mark Hammer]

Then either remove the other K30, or cut the trace that brings the clean signal to the output buffer.

[jimosity]

Thank you sir, that did the trick.