Rangeblaster problem (NOOB)

Started by krochi, May 26, 2012, 05:09:11 PM

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krochi

Hello,
I've built a rangeblaster from fuzzcentral (http://fuzzcentral.ssguitar.com/rangemaster.php). This is my first pedal, and it's really a trouble booster. It gives no sound when the pedal is on. When bypassed, it works fine. I've checked the board a lot of times, but could not see a problem. I used a 2N388A NPN. I've also used a 5,6 nF capacitor instead of 5 nF.
Than I measured the voltages on the transistor pins:
C: 7.3 V
B: 1.04 V
E: 1.11 V,
which is not right, as the base must be higher in the NPN transistor. What can be causing it? Is the PCB at fuzzcentral correct?
I would appreciate any help.

smallbearelec

You say that you "checked the board." How did you build? Did you make your own PCB, or did you hard-wire on perf? Either way, I would do a continuity test from point-to-point, referring to the schem. Likely you will find that something is either not connected or not wired correctly.

krochi

#2
I made a PCB, took it from fuzzcentral. I just don't understand how emitter gets more positive voltage, than the base.
UPD: resoldered the board, now it works. Don't know, where the problem was, though.

smallbearelec

Quote from: krochi on May 27, 2012, 07:26:14 AM
I made a PCB, took it from fuzzcentral. I just don't understand how emitter gets more positive voltage, than the base.
UPD: resoldered the board, now it works. Don't know, where the problem was, though.

Most likely there was a connection not being made, re-soldering fixed that and the Base was then biased correctly. FWIW: I would not have recommended making a PCB for a first build; that's a fairly steep learning curve. I am glad that you succeeded, perhaps aided by the fact that it's a pretty simple pattern. Now that you have done this, I would suggest backing up and hard-wiring something basic on perf or veroboard, just for the experience.

Happy Construction!
SD