Beginner project trouble-shooting

Started by RJ, October 25, 2003, 11:26:37 PM

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RJ

Hi everybody, I hate to be a pain and ask very beginnerish questions but I was hoping I could maybe get some guidance with debugging my first project.  I'm trying to build the NPN Boost by Gus Smalley, the beginner project in the other forum...here's the schematic:

http://www.diystompboxes.com/sboxforum/viewtopic.php?t=763

I've assembled the board, but I'm not getting any output from it...I've read through the debugging guides here and at R.G. Keen's website and collected some voltage figures, but I'm not sure what the next step to take is.

I've verified that there is 9.4V to the 10k and 100k resistors that are connected to the power.  I believe the transistor is oriented the right way, I checked the datasheet for it (it's an NTE123AP, which I was sold as being a 2N5088 equivalent),  the voltage measurements are:
E = 2.98V, B = 2.99V, C = 8.84V.  
There is 5.34V to the output jack.  The input and output wires are connected directly to the jacks, I don't have a switch in the circuit yet.

For the 10 mF cap that goes to the output I had to use an axial type...I'm not positive it's oriented the right way, it's not clear on it which side is positive and which is negative.

Are any of those voltages a clear indication of a problem with the circuit?  If the 10 mF cap was in backwards would I get no sound through the circuit?  Any tips would be greatly appreciated, sorry if it's something really obvious.

petemoore

Ill give it a go with what I know.
 being a positive power supply, if the 10uf connects to ground the negative would connect to ground, if it is being used as a DC blocking [output cap] then the negative would go toward the output the pos would go toward the ckt.
 I think the voltages you're reading won't allow the transistor to amplify, I would ~double check resistor color codes and wiring.
Convention creates following, following creates convention.

nightingale

yeah~
the readings are a bit  strange. recheck your wiring, and the cap might have a row of - symbols with a directional arrow pointing to the - side. and as pete suggested. double check all of your resistor values.
hth,
~ryanS
be well,
ryanS
www.moccasinmusic.com