Assembly and Testing
Level 1: The MDD can be rapidly constructed upon a standard "perf" board. At this time there is no plan for a PCB layout.
Construction should be done in stages to facilitate correct assembly. The partitioning of the circuit design allows this incremental circuit realization.
The first level of construction includes the MIDI Interface. Building this sub-set of functionality test's the Microprocessor, the Opto-Isolator, and the Non-Inverting Buffer. This level of circuitry is a fully functional MIDI Filter in that MIDI messages input to the device will issue out of the MIDI OUT in Running Status Mode. The sub-schematic of this level of construction can be found here.
Level 1: First check the distribution of power to the integrated circuits prior to connecting to a power supply.
Ground should be found on:
Pin 5 - U1, Pin 10 - U2, Pin 7 - U3.
+5 Volts should be found on:
Pin 8 - U1, Pin 20 - U2, Pin 14 - U3