Bringing old effects back to life -
We've all heard the story.
"Hey, I found this in the basement! It was dirty and covered in cobwebs,
but when I cleaned it off, I found out it was a vintage Fuzz Face!! This thing's
worth a mint! I've always wanted one of these. It doesn't work, though..."
The trick is to make it work, and to coax those once-living dulcet tones from
the old box. Here's how.
- Get it clean
Use a household vacuum cleaner with the brush attachment and gently vacuum all
the dust and grime off. For sticky, oily dirty residues, use isopropyl alcohol
and a soft brush and clean the board, switches, wires, case, etc. Let it dry.
Vacuuming it again is a good way to dry it.
Do NOT use cleaners that may leave conductive residues.
- Get the mechanical parts working right
Twiddle the pots and feel for scratchiness. If the pots are not sealed,
squirt in a bit of non-residue contact cleaner while you twiddle the pot.
Use contact cleaner on the switches if they're an open-contact type.
Test closed-case switches for proper operation with an ohmmeter
Clean inside jacks with a squirt of cleaner and a paper towel
- Look for burned, broken, or missing parts
... or just decayed parts. Sometimes you'll find a little dried-fluid kind
of smear around old electrolytic caps. Those are goners for sure.
- Fix broken wires
Sometimes you'll have to do some detective work to figure out where they go
if more than one is broken. Usually these things break off right at the end
of the insulation where the wire is stripped and soldered either at the
control/jack end or the board pad end. There isn't any magic to help with
this one - you just have to find a schematic to get it right or guess. This
is not as bad as it sounds - with only two wires loose, there is only one
wrong way to connect them. With three wires loose, there are five wrong and
three right - not too bad.
- Replace all the electrolytic capacitors
Just do it. Make a list of the capacitance and value of each one, and order
replacements of the same style (radial or axial). In general, the
replacements will be smaller, so fit is not a problem unless you get much
bigger voltage-rated replacements.
To remove them, rock the capacitor up gently from the component side while
melting the solder on the solder side. When that lead comes out, rock the
other lead out.
Then poke a wooden toothpick into the hole in the board while melting the
solder on the pads to leave the holes open for the replacement caps.
Be very, very, very, careful on phenolic or paper based PCB stock (that is
non-fiberglass-epoxy) boards to get in and out fast with your soldering
iron, and to NOT stress the copper pads and traces. They don't hold all that
well, and when heated, they'll often just lift.
- Resolder all the joints
Touch each solder joint with a hot iron and a tiny bit of fresh rosin core
solder just enough to remelt it to a nice, shiny surface.
Do NOT press hard with the iron and lift the pads.
- Replace other parts as needed from any other debugging you've done.