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DIY Stompboxes => Building your own stompbox => Topic started by: wui223 on May 15, 2005, 06:35:30 PM

Title: Millinieum Bypass
Post by: wui223 on May 15, 2005, 06:35:30 PM
I worked out the bypass circuit, but it doesnt work, the LED didnt lid why? I use BS170 for FET and 2N3904 with emitter left open for the low leakage diode. What are the value of limiting resistor for LED should i use?
Title: Millinieum Bypass
Post by: KORGULL on May 15, 2005, 07:12:44 PM
Something like 1K - 4.7K should do for the current limiting resistor.
Double check the Millennium's connections to +/-  power and the connections at the switch.
If you're using Millennium 2, do you have the second, regular diode (1N914) in there?
Title: Millinieum Bypass
Post by: wui223 on May 15, 2005, 08:45:05 PM
Yes i double check already. everything in place but no light.
Title: Millinieum Bypass
Post by: darren on May 15, 2005, 10:24:57 PM
Take a deep breath, and triple check.  8)

check for solder bridges.

Desolder the LED, check it works.  Measure the voltage at the LED anode, make sure it's 9V.  download the datasheet for the mosfet you'reusing, check you have the legs the right way round.  do the same for the 2n3904.  swap out the mosfet, maybe it got fried.

telling me you double checked everything doesn't help cos clearly it doesn't work so you missed something!!!!   ;)

measure the voltages everywhere and post em so we can pull it to bits.

good luck...
Title: Millinieum Bypass
Post by: wui223 on May 16, 2005, 04:29:46 AM
i got the light already but i modify the circuir 8) i disconnect the low leakage diode (2N3904) and it works. WHY?
Title: Millinieum Bypass
Post by: wui223 on May 16, 2005, 07:46:02 AM
How to improve the brightness of LED ?
Title: Millinieum Bypass
Post by: TheBigMan on May 16, 2005, 04:20:43 PM
Change the limit resistor if the LED brightness isn't what you want.  Lower the value to brighten it and vice versa.