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Sunking II *Problem Solved*

Started by jball85, March 25, 2015, 01:00:40 PM

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jball85

Second Sunking II build here, the first worked perfectly, this one doesn't. I'm getting no bypass signal or effect signal, and the LED will not light up either way. The only major difference between this one and the last one parts wise is a different BS 250. The BS 250's I ordered look fake, I bought them off ebay from a US seller as I needed them quickly, over 70 were sold and no one has complained about these transistors on the sellers feedback. I'm going to try to reverse it to see if I got the pin out wrong. However, I'm not even sure what the purpose of this transistor is or whether It could possibly be the culprit. Everything else looks great, the wiring is correct, no solder bridges, no dry joints, good battery. I check each and every part (caps, resistors, diodes) before they are soldered into the board. I'm going to check the switch right now. Switch works fine. This pedal was supposed to be finished and shipped for a paying friend this afternoon. Murphy's Law strikes again.  >:(

Any ideas would be greatly appreciated.

mgwhit

If the LED doesn't light up and you don't get bypassed or effected signal, you've either got a power issue at or around Q1 and R32 (as you've guessed) or you've miswired your switch.  (I'm assuming you've wired this up for buffered bypass.)  If you're 100% sure your switch works correctly, then check out the power.

Do you have 9V after Q1 or on R32?  If not, you can jumper Q1 drain-to-source, either with a wire or a 1n5817 diode.  That MOSFET is just there for polarity protection.

jball85

I took the pedal completely apart and desoldered the BS 250, then flipped the tranny 180 degrees. It works now. As previously mentioned these BS-250's were absolutely funky looking package wise. Hell, they look home made. Problem solved, thanks for the quick response either way man. I appreciate it.

mgwhit

Cool.  Glad you got it sorted out.