So that this test unit can be powered by the LCD controller without requiring an external power supply (it can handle DC input voltages as low as 5V and up to at least 12V), identical low loss Schottky diodes were fitted (cathodes to D2 cathode, one diode anode to LCD interface Pins 1/2 and the other diode anode to Pins 3/4).
On the LCD interface adaptors, the unmounted B+ diode and RC network for ground loop isolation was shunted to enable the LCD controller to power this test unit.
Note that the Main B+ from the cathode of D2 is only connected to the inputs of DC-DC converters and nowhere else; D2 anode is connected to the centre pin of the DC input jack which has no other connection.
On the LCD interface adaptors, the unmounted B+ diode and RC network for ground loop isolation was shunted to enable the LCD controller to power this test unit.
Note that the Main B+ from the cathode of D2 is only connected to the inputs of DC-DC converters and nowhere else; D2 anode is connected to the centre pin of the DC input jack which has no other connection.
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