Quick Reference#

Quick lookup tables for common repair tasks.

Transistor Test Quick Reference#

NPN Transistor (e.g., 2SC series)#

                Collector
                    │
                    │
              ┌─────┴─────┐
     Base ────┤           │
              └─────┬─────┘
                    │
                    │
                 Emitter

Test (Diode Mode):
  Red on Base, Black on Emitter: 0.5-0.7V ✓
  Red on Base, Black on Collector: 0.5-0.7V ✓
  All other combinations: OL ✓

PNP Transistor (e.g., 2SA series)#

                Collector
                    │
                    │
              ┌─────┴─────┐
     Base ────┤           │
              └─────┬─────┘
                    │
                    │
                 Emitter

Test (Diode Mode):
  Red on Emitter, Black on Base: 0.5-0.7V ✓
  Red on Collector, Black on Base: 0.5-0.7V ✓
  All other combinations: OL ✓

N-Channel MOSFET (e.g., 2SK series)#

              Drain
                │
        ┌───────┤
  Gate ─┤       │
        └───────┤
                │
              Source

Test (Diode Mode):
  Gate to Source: OL both ways ✓
  Gate to Drain: OL both ways ✓
  Source to Drain: May show body diode ~0.5V

Voltage Rail Quick Check#

Current Limits for Testing#

Resistance to GND (FETs Removed)#

Component Cross-Reference#

Transistor Equivalents#

Always verify specifications match, especially voltage ratings and Vgs threshold for MOSFETs.

Pinouts#

uPC494 (IC920)#

         ┌───────────┐
   1 NFB │1    U   16│ GND
   2 NFB │2        15│ DTC
   3 IFB │3        14│ Vref
     GND │4        13│ Out B
      Ct │5        12│ Vcc
      Rt │6        11│ Vcc
     GND │7        10│ Out B
   Out A │8         9│ Out A
         └───────────┘

NJM4565 (IC501-518)#

         ┌───────────┐
  Out A  │1    U    8│ V+
  -In A  │2         7│ Out B
  +In A  │3         6│ -In B
     V-  │4         5│ +In B
         └───────────┘

Service Manual Page Reference#