1/15/2015

Circuit testing and debugging

Everything fired up first go. The channel boards contain the PLL, VCO, waveshaper, ringmod, VCA, lock indicator and various related electronics. There are two identical channel boards, capable of operating independently from each other, but really designed with cross-modulation in mind. Each board is controlled from a 8-bit parallel data bus. Many features are jumperable the board is laid out for easy experimentation with features. There are so many possible configurations! Testing everything as a complete unit is difficult due to the sheer complexity of the PCB interconnect wiring and front panel control stuff. So I've been breaking it down into smaller parts, "divide and conquer".

One of the two 'channels' near completion.


Digital control board, PIC goes in the empty socket.

Two identical 'channel' boards.

Analog Harmonizer/Octaver PCBs

Lots of progress has been made during the last 6 months.
Design finalized, circuit prototyped, PCBs designed and manufactured,
components fitted, circuit tested and debugged (partly still in progress) ..
Some of the pre amp and fundamental extraction circuitry is built by hand on perfboard or breadboards. The remaining boards, 3 double-sided and 1 single-sided, are all done. 
Making your own boards like this is hardly worth it considering how relatively easy it is to have a board house make the PCBs for you. However, buying this many boards from a fab house would be pretty expensive, especially when I probably won't bother with more than one unit. So in this case, a single run, prototype through hole. 
Some photos of the etching process;

Sample of the PCB designs.

Developed PCB.

Etching in a etching tank.

Preview of the result.

All PCBs etched.