CGS D/A converter

CGS11 the CGS D/A converter board was really developed for Ken Stone's own use, to allow HIS 486 based sequencer to connect to various VCOs etc. It has twelve bit resolution, and four "gate" outputs, though these only output around 4.5 volts maximum.

The design of the board here has not been tested.

How to use this module
This module is designed to connected to either a 16 or 8 bit bus, and contains two latches that can be latches independently. For a backplane/bus common stripboard may be used, along with 0.1 pitch 90° headers. It can be used with the parallel port adapter for IBM PCs parallel port adapter], which is how Ken used his. Software is up to the individual.

While untested, the analog portion of the module should work on 12 volts. The digital portion requires 5 volts.

A little on how it works
Ken avoided using commercial D/A converters for a few reasons, including stability, and availability.

Construction
Before you start assembly, check the board for etching faults. Look for any shorts between tracks, or open circuits due to over etching. Take this opportunity to sand the edges of the board if needed, removing any splinters or rough edges.

When you are happy with the printed circuit board, construction can proceed as normal, starting with the diodes and resistors first, followed by the IC sockets if used, then moving onto the taller components.

Take particular care with the orientation of the polarized components, electrolytics, transistors and ICs.

When inserting the ICs in their sockets, if used, take care not to accidentally bend any of the pins under the chip. Also, make sure the notch on the chip is aligned with the notch marked on the PCB overlay. Please note that the CMOS chips are static sensitive devices, so make sure you handle them correctly.

Parts list
This is a guide only. Parts needed will vary with individual constructor's needs.

CC-BY-NC
Readers are permitted to construct these circuits for their own personal use only. Ken Stone retains all rights to his work.