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Millenium mystery

Started by 6stringer, March 06, 2006, 11:05:15 PM

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6stringer

I've just completed (almost) a second Rodent pedal, using JD Sleeps layout.   
It works perfectly except the LED will not come on with the circuit is engaged.   
The LED tests perfect with checked with a battery and equal value resistor off the PD board.
I've check the all components in the circuit, especially the parts of millenium portion of the circuit, values and voltages, all check fine. 
I compared it to the first Rodent I built and it looks identical.   I've gone over it several time and now I don't know where to look next. 
Any ideas???

Toney


How did you go about the millenium? On/off board? Which version?
Should be able switch with the control wire to ground.
I think the most common millenium problems are: blown mosfet (static sensitive) and lack of resistance to ground from the circuit output.

6stringer

Thanks for the reply,  I beleive it is a Millemium 1.   The link to the layout I built: http://www.generalguitargadgets.com/diagrams/rodentpl.gif
I checked the voltages from the transistor, the resistors and it seems to be on par with the other pedal I built that works fine. 
How do I check for resistance to ground?
Thanks

Toney

 In this case, since you already have an identical working version and it's on a verified board, simply get out the multimter check the voltages around the millenium components in on/ off states.
But first, quadruple check for component orientation/wiring/pinout/soldering errors.
Good luck.









6stringer

I compared the voltages between the know good millinium circuit and the new one
that does not work, even though all the components tested good, I changed out
the 2n5485 and the 4k7 resistor anyway (no change in performance).
The voltages from the known good circuit are:
Battery voltage: 8.81v
With circuit on:
Transistor voltages 8.66v, 8.41v, .033v
From 4k7 to LED: 1.81v
With circuit off:
8.71v, 2.37v, 00v
From 4k7 to LED: 1.51v

Voltages from new (non-functioning) circuit:
Battery voltage: 9.27v
With circuit on:
Transistor voltages 9.27v, 8.80v, .035v
From 4k7 to LED: .394v
With circuit off:
9.27v, 1.76v, 00v
From 4k7 to LED: .394v

Obviously, the voltage to the LED is different, I have no idea why.  Any idea what's going on here?
Thanks for your help.