Had Harbinger one working i got a spark now all i get is major hum SOLVED

Started by Strassercaster, March 24, 2015, 08:12:05 AM

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Strassercaster

Hello I built my harbinger and finished a few weeks ago. I took my time drilling and painting the box. It was working perfectly and sounded amazing. I went to put my light shield on it permanently. Well its metal and Like an idiot i had it plugged in. I touched the metal across resistors R29  r 30 r35 R37 and C16 and man i got some sparks. So i tested it again and on or off i get a major hum like touching the end of the cord. No signal on or off. I went to check my lm7815 and i shorted it out. I had a spare and fixed that. I then switched lt1054 chips i had one in a charge pump for a tonebender i built. The lt1054 from the harbinger worked in the other charge pump. This is a 9v build with no mods.

  So then i started checking transistor voltage. I am getting up and down readings on the E and B of several transistors. They range from 5.5-9.5 volts five reading per second very fast fluctuations. I am stumped. I had it working and did a bozo move . The light bulb still pulses and the speed control works.On or off its loud hum period. I keep thinking i have a ground issue . I have voltage everywhere.I tried changing a couple of electrolytics and one or two 1 uf caps. I doubt a resistor is going to go bad on such low power. I wrote down the lt1054 readings . They were not perfect compared to another post but i am pretty sure the chip is good  because it does work in another charge pump. I replaced the lm7815 due to another bozo move. Is it normal for voltages on transistors to fluctuate like this in a univibe circuit???The speed knob does not have any effect on the voltage fluctuation . I will give  chip and transistor voltage readings and post a couple pictures later tonight when i get home . man i hate the idea of just replacing random parts.I figure i could buy another one build it and then have a benchmark to go off of. Please help I am very frustrated ha ha. Thanks Madbeaners for you time wisdom and knowledge.

skeeter

I couldn't get my 2015 version to work no sound at all ,so I touched the under side of the pcb while I strummed and got sound ,my finger was an audio probe ,so I shorted a few resistors  r5 & r6 etc and got sparks then audio, the pedal fixed its self ,apart from distortion when I strum hard in v&m modes ,so I may change the J201 to a MPF102