Populating the TM3030 PCB
For general information on how to build Oakley projects, including circuit board population,
mounting front panel components and making up board interconnects please see our generic
Construction Guide at the project webpage or http://www.oakleysound.com/construct.pdf.
There are a few things I ought to draw your attention to that are not covered in the
Construction Guide.
1. The 4MHz crystal should be soldered into the board so that its bottom surface sits above
but not against the top surface of the printed circuit board. A small gap of around 1mm is
recommended.
2. The positive temperature coefficient (PTC) resistor is mounted so that is lies across the top
of U6. This is to ensure that both it and U6 are at the same temperature so that the resistor
can compensate for the temperature dependency of the VCO control circuitry.
A close up of the VCO circuitry of the TM3030. Note the positioning of the positive temperature
coefficient (PTC) resistor. Although not used here, a small amount of thermal paste can be used to keep
both U6 and the PTC at the same temperature.
3. If you are not fitting a 2SC1583 to the filter circuit then you need to use a matched pair of
BC550B or BC549B transistors. In theory these should be perfectly matched and thermally
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