Yamaha YFM660RN Service Manual page 315

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3.Voltage
Connect the pocket tester (DC 20V) to the
bulb socket coupler.
Tester (+) lead → Red/Black terminal 1
Tester (–) lead → White/Blue terminal 2
Turn the main switch to "ON".
Check the voltage (12 V).
4.Diode
• Remove the diode from the coupler.
• Connect the pocket tester (Ω × 1) to the
diode terminals as shown.
• Check the diode for continuity as follows.
Tester positive probe →
Blue/Black 1
Tester negative probe →
White/Blue 2
Tester positive probe →
White/Blue 2
Tester negative probe →
Blue/Black 1
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C0NTINUITY
MEETS
SPECIFICATION
Continu-
ity
No conti-
nuity
CORRECT
8 - 34
SIGNAL SYSTEM
OUT OF SPECIFICATION
The wiring circuit from the main switch to the
bulb socket connector is faulty, repair it.
OTE:
When you switch the tester's positive and
negative probes, the readings in the left
chart will be reversed.
INCORRECT
Replace the diode.
– +
ELEC