Millenium problem, again...

[Renegadrian]

I did search the forum, and others have had the same problem as me...Still I cannot figure how to solve the problem...
basically I built a bazz fuss for a friend and boxed with the milenium...the LED is always on.
I didn't put the 100k res. at first, now I also tried 1M - the same light...
please someone explains me where I go wrong...
thank you

I used this layout

[chris_d]

I have used this same Torchy layout for this circuit several times and have not run into the 'always lit' problem, but it is a known possibility, and also the reason for R.G. Keen's later Millenium revisions, as noted here:

http://www.geofex.com/Article_Folders/Millenium/The%20Next%20Millenium.pdf

Perhaps check out one of those revisions instead. Or, alternately, maybe try to source a different batch of JFETs and hope that you get lucky. You might even find that you have a usable one in your batch already other than the one that isn't working for you at the moment.

-chris

[R.G.]

I did search the forum, and others have had the same problem as me...Still I cannot figure how to solve the problem...
basically I built a bazz fuss for a friend and boxed with the milenium...the LED is always on.

This is nearly always caused by the MOSFET pins being reversed, or a solder short. The MOSFET has an internal diode which has anode to source and cathode to drain. Get it backwards and the diode always conducts, lighting the MOSFET.

The BS170 has at least TWO pinouts from different makers. You MUST look up the right one (or just keep rearranging them until you get the correct one. )

Perhaps check out one of those revisions instead. Or, alternately, maybe try to source a different batch of JFETs and hope that you get lucky. You might even find that you have a usable one in your batch already other than the one that isn't working for you at the moment.

He's using the Millenium 2, which uses MOSFETs, not JFETs. Device variation is not a problem with the Millenium 2.

[chris_d]

He's using the Millenium 2, which uses MOSFETs, not JFETs. Device variation is not a problem with the Millenium 2.

Aw man, i usually pay much better attention than that! 

-chris

[Renegadrian]

THX for replying!!! 

[R.G.]

So did flipping it over get the Millenium to work?

[Renegadrian]

well, actually the bs (the mosfet, I mean, not bulls..t!!!)  <---(sorry I'm an idiot... ) is soldered on the perfboard...So I have to desolder it , not done yet, or build another one, on vero or perf...
I'll try...

[Auke Haarsma]

my bet is on a dead bs170. Happens (too) often to me too.

[Renegadrian]

Built another one on Vero, with the socket for that BS (yeah, I mean bulls..t this time... )
Now it doesn't turn on at all...Grrrrr....

[Auke Haarsma]

Can you measure the voltages on the BS170 in the on and off position?

[Renegadrian]

No, I still lack of a DMM, so no measurements...

[Auke Haarsma]

Ok, than just drop in another BS170 (if you have one). If that one does not work either, I am pretty sure this time it is not the BS170 causing the prob but something else.

[Auke Haarsma]

And, you could try to remove the BS170, jumper Source to Drain and see if the LED lits up (it should).

[Renegadrian]

OK, I just f..ked up a couple of mosfets, but I got it working now...THX for the suggestions! 

Now, I didn't put in the 100k res - shall I have to? What is that for?

[Auke Haarsma]

it is there to provide a way to ground if the effect itself does not have it.

Every effect with an output volume pot already has this, so in that case it is not needed. I've never needed that 100k resistor.

[Renegadrian]

Ok, got it - now the bAzz fUss is working good...my friend will be so happy...