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Projects => Tech Help - Projects Page => Topic started by: jazzmandjango on October 15, 2019, 04:58:18 PM

Title: Harbinger 1.5 Build Help - Low Volume / Ground Not Neutral
Post by: jazzmandjango on October 15, 2019, 04:58:18 PM
Hey all,

I'm pretty new at building pedals, so I might've bitten off a bit more than I can chew with this one, so bear with me.

(1) Project Name - Harbinger 1.5 (running at 9v, not 18v)
(2) General description of the problem - The effect works--the lamp oscillates, I can switch between chorus and vibe effects, volume and frequence pots work properly, but the volume when engaged is very low, and when I check my voltages the ground on the regulator and IC are reading at 2.6v instead of 0, details below). So I'm worried something is off that is keeping this effect from working perfectly!
(3) Steps that you have taken to try to resolve the issue - Cleaned up and trimmed my solder joints, measured my voltages but not sure how to proceed with info I've gotten. Trying not to desolder and replace parts at random before I get a bit more advice...
(4) List any substitutions you used for parts/values - This is where i suspect I may have screwed things up. I substituted BAT46 diodes for D1-3, which should be 1N5817s. Could this be the cause of my grounds not equalling 0? Would it be better to replace with 1N5819s (which I have on hand) or should i order some 1N5817s?

I also substituted a few resistors for pairs of resistors in series. R8 (5k6) is a 5k1 and 510R in series, R14 (1k2) is a 1k and 220R in series, and R43 is 2 1Ms and 2 100ks in series, but I don't think that's causing any problems other than being an eyesore.

Here are my voltage measurements, everything seems okay except the C on Q3-10, which are 2v below on average, and my Gnds on the Reg and IC, which are 2.6v above 0:
Q1 - C - 2, B - 1.35, E - .98
Q2 - C - 4.2, B - 2, E - 1.44
Q3 - C - 11.9, B - 4.2, E - 3.64
Q4 - C - 15.6, B - 4.98, E - 4.62
Q5 - C - 11.6, B - 4.6, E - 4
Q6 - C - 15.7, B - 5, E - 4.6
Q7 - C - 11.6, B - 4.6, E - 4
Q8 - C - 15.7, B - 4.9, E - 4.6
Q9 - C - 11.7, B - 4.6, E - 4
Q10 - C - 15.7, B - 6.3, E - 5.8
Q11 - C - 14.3, B & E fluctuate
Q12 - C, B, & E all fluctuate
Q14 - D - 15.7, S - 1.18, G - .8
REG - IN - 15.7, GND - 2.6, OUT - 14.3
IC1 - 1 - 1.3, 2 - 4.6, 3 - 2.6, 4 - 6.4, 5 - 2.6, 6 - 2.56, 7 - 1.4, 8 - 8.7

I've attached pictures of the front and back of the board as well.

Thanks for your help, really appreciate the guidance as I get the hang of this!