Before we start any construction, let's make a couple of things perfectly clear about
the complexity and skill levels needed to build the DSP Musicolour.
(1) This project is not suitable for beginners. In fact, you
should not attempt to construct this project without considerable experience,
particularly with mains devices.
(2) This project controls mains (230/240V or 110/120V)
voltages. Mains voltage can be lethal. Hence it is
especially important to double check and be certain that mains power is not
applied whenever working with the PC boards.NEVER apply
mains power to the main PC board unless it is fully enclosed in a plastic case
with the case screws done up.
All the parts in the red shaded area on the Main Board
component layout diagram (Fig.3) operate at mains potential (ie, 240VAC) and
contact with any of
these parts could be FATAL.
These parts include the PC tracks, the opto-couplers (OPTO1-4),
the Triacs, the 100mH inductors, the 680W resistors, the 100nF 250VAC capacitors, screw terminal blocks CON4-CON6,
the transformer primary and the wiring to the mains input and output sockets.
DO NOT TOUCH any of
these parts unless the power cord is unplugged from the mains supply. DO NOT
CONNECT this device to the mains unless it is fully enclosed in the specified
This project is not for the inexperienced. Do not build it
unless you know exactly what you are doing and are completely familiar with
mains wiring practices and construction techniques.
Construction: Display Board
The main and display boards assembled in the case, before the rear panel (and rear panel wiring) is fitted. This prototype photo has single-sided PC boards - production boards should be double sided to eliminate most links. However, if you etch your own PC board it will probably be as per the prototype and require links as shown above.
The DSP Musicolour is built on two separate PC boards. The main
board consists of the Triac output section at 230/240VAC mains potential and the
low voltage section containing the op amps and the dsPIC30F4011 microcontroller.
The two sections of the main board are isolated by optocouplers and the mains
transformer. The vertical display board is all low voltage circuitry and its
supply rail is +5V.
We'll begin the construction with the display board, which is
coded 10107082 and measures 247mm x 76mm. Note: our prototype DSP Musicolour
used single-side boards with many links, however kitset suppliers are likely to
provide the boards in double-sided form with plated-through holes, in which case
only a few links will be necessary.
First, you should check the PC board for hairline cracks in the
tracks and any visible shorts between tracks. Fix any defects.