Author Topic: Help with a Rustbucket build  (Read 587 times)

Dr Tony Balls

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Help with a Rustbucket build
« on: December 05, 2023, 10:31:05 AM »
If anyone is feeling particularly bored and in the mood to help I've got something that could use extra pairs of eyes and some expertise.  I'm not even sure if it belongs in this sub-forum but its so Rustbucket without being on a purchased Rustbucket PCB so here goes....

Rustbucket on Vero.  I'm a masochist apparently, but I was asked about building an Attack Decay and since I do 99% of my stuff on Vero and like a challenge, I decided to give it a go.  Enter the Rustbucket project files because 1) its a clean schematic that's been verified, 2) it has the necessary appointments to the power supply for DC power, and 3) it has support in the form of printed reference voltages and (potentially) folks experienced with circuit.  So I'm very grateful to have the work of Madbean to start from here.  Here's the Rustbucket Project Files.

The layout is a 1:1 from the Madbean schematic, using matching part numbers to make it easier to troubleshoot.  A couple of notes related to it and how I make layouts:
  • I like to color-code source voltage traces for clarity.  In this case I have ground, input voltage (+18-24V), +15V, -15V, and the supply rail for IC7, IC8, and IC10
  • For space saving I have removed unused pins from ICs.  All of the ICs are socketed, so I just snip the pins off the socket before soldering.  Snipped pins are labeled on the layout with an 'X'
  • All of the standing diodes are cathode (stripe) up with the exception of D8
  • There are two holes labeled 'Q'  which are connected via a jumper wire.
  • The notch in the bottom left corner is a board cutout to allow room for the switch, the whole thing fitting in a 1590DD

And the layout (larger image):



I've been over it many many times and caught a few errors and revised it.  The layout now seems correct to me and I've been over and over the test build and everything looks correct in terms of part placement and trace cuts, but there is something erroneous going on.  It's passing signal, and reacting *sort of* as it should.  I'm getting swells and the attack and decay controls are working, but its very distorted and glitchy sounding.  Testing my voltages against the reference voltages and there are inconsistencies.  Here's the reference voltages and mine in red, when they are inconsistent:



I'm using tildes (~) to note that the voltages are jumpy in those locations.  Using the problem voltage areas I traced over the schematic to show my areas of concern (where I'm getting off voltages) and I came up with this (larger image):



So clearly things are going awry somewhere in the IC7/IC8/IC9/IC10 region.  I've tried replacing ICs in these locations but cant seem to get any changes in regards to voltages.

So....I understand that this is a Herculean ask, but if anyone is feeling particularly adventurous and wants to lend a hand here I'd love some help trying to figure out where I'm going wrong.  ANY HELP IS MASSIVELY APPRECIATED.