Oddy VCO IC

[Tony Allgood]

Hi all,

Just got an old mk2 Oddy with old style mk 1 VCO board fixed. The VCO
uses a CD4011AE in its core. The previous repairer had got it to go with
a more modern CD4011BE, and a horrendous cludge that involved linking
the output of the gate to the VCO reset line via a 0.1u cap. Suprised it
worked at all. In fact, connecting the cap from the gate to the positive
rail also did the trick too.

However, this was all too much for me, so I got rid of the cludge
altogether and replaced the IC with a 4011UBE. I am guessing that the
unbuffered version of the IC is probably similar to the A versions. Am I
right? It certainly works now very well, although I had to recal every
trimmer in the thing and fix the square wave output too.

One of the switches had been horribley mangled too. The 'repair' guy had
taken out the innards of the thing and replaced it with half the innards
of a new switch. Unfortunately, it wasn't compatible and ended up
falling to peices... I couldn't find a replacement so I had to do a
little cludge too; I soldered a whole new slide switch under the hood of
the old switch housing. Nice and sturdy, and worked a treat too. But for
future reference, does anyone know of a source for those PCB mounted
slide switches?

Regards,

Tony Allgood  Penrith, Cumbria, UK

Modular synth circuits, TB303 clone and Filter Rack

http://www.techrepairs.freeserve.co.uk/projects.htm