millenium bypass problem!

[tsaf]

hello!
yesterday i built a distortion pedal(dr boogie),and today i tried to put the millenium board(the one with bs170,1n914 and led)
the problem is that the led stays always on and ,and when i want to turn off the effect there is no signal..has anyone a solution?
thanks

[bluebunny]

The LED will stay on (or at least, it will go off, but fade back in a short while later) if there's no route to ground (been there, done that!).  But I don't think this is the case for you, since the last thing in the Dr Boogie circuit is the volume pot, which is wired to ground.  The fact that you also get no signal when bypassed suggests that the wiring of your switch perhaps has an error?  Any chance to post a picture so we can take a look?

BTW, I've built lots of Milleniums (M2 version) and I've never managed to kill one, even with the abuse they sometimes get.  You can check the Millenium on its own: just take the control line to ground to see if it switches the LED off (with power applied to it, of course).

[tsaf]

i have used a wrong value for the resistor...now i used a 2k2,and i can change on/off of the effect..but the led is still on

[R.G.]

1. Are you sure the MOSFET is inserted correctly? Reversing source and drain will leave the LED on all the time.
2. As BB says, the lack of signal is indicative of a wiring problem.

[bluebunny]

1. Are you sure the MOSFET is inserted correctly? Reversing source and drain will leave the LED on all the time.

Did exactly this on my very first M2!!   

And thankfully never since...

[tsaf]

at last,the problem was that the fet was fried....!

[R.G.]

at last,the problem was that the fet was fried....!

I sympathize. MOSFETs are a bit fragile until they get into the circuit and the protective components that are put there by all good designers if the MOSFET doesn't have them internally.

The gate really is insulated by a layer of glass only 20V thick. Handle carefully.

[duck_arse]

well, now, I've got me a millenium problem, different to the rest, it seems.

a mill 2, with bc847 and mmbt4148 for gate diodes, 2n7002 with gate resistor, all hung from a 100k vol pot at the end of a fetzer. engaged - led lights as expected. bypassed - led brightness follows vol pot setting.

I have not yet pulled the built circuit from the box, a job I don't want to do, and so far I've only probed for continuity. switch is good, wires to right places for bypassing, no short on/across output cap or vol pot.

can anyone point me to something obvious?

[samhay]

Leaky output cap?

[duck_arse]

well, I dunno. more probing today shows the fetzer works, the bypass is good, but when bypassed, there is 1V7 on the pot wiper. dunno where the volts is coming from, or why. or how it's getting to gate, for that.

hmmmm ..... and I'm not sure this is a "millenium bypass problem!" so much as a "millenium as problem indicator". but the problem is the rub.

[Kipper4]

Rub a Duck 
I'll leave that there.

[MrStab]

Rub a Duck 

i think you can go to jail for that

[Kipper4]

Lol
Do not pass Go, Do not collect 200 pounds

[duck_arse]

don't make me find that fish photo, rich.

hmmmm ..... and I'm not sure this is a "millenium bypass problem!" so much as a "millenium as problem indicator". but the problem is no rub.

I retract this first statement. it should now read "millenium indicating a futzed fet". dunno what the problem was, but after hacking in a HUGE TO92 replacement part, the millenium is 'working' (but still unattached, pedal unassembled, go unpassed, duck unrubbed).

[edit :] I will add that the dud part was a sample direct from the Supertex people, not a lucky-dip tayda part.