Diagnoses H (High), L (Low), F (Floating), and P (Pulsing). Using IC1 a dual comparator: CA3240, IC2 & IC4: CMOS 4001 Quad-NOR Gate, IC3: CMOS 4011 Quad-NAND Gate, plus TR1: BC107, and TR2-4: BC557 LED driving transistors. Pages 32-46 includes circuit pictures, block diagram, circuit diagram, Upper and Lower PCB legends and tracks, mechanical assembly diagrams, and component list.
7-segment Logic Probe Case
Logic Probe Tip
Tip Assembly Instructions