Samsung MC26AC2-07, Service Manual

Page: 31 / 66

Samsung Electronics 5-6
Troubleshooting
(2) Procedures for checking the outdoor unit.
Turn off the power, and then turn on the
power in 5 seconds.
Does the compressor operate in 2 minutes after
the relay (RY71)
is activated at the indoor unit after 3 minutes?
Does the photo coupler (IC02, IC03)
corresponding to the indoor units (B & C) operate?
Is the DC voltage applied to both ends of the C901?
(1) Is the voltage DC6V when either of the indoor
units (B & C) is turned on?
(2) Is the voltage DC8V when both of the indoor
units are turned on?
(1) Does the N01 pin output of the IC04 maintain "Low"?
(2) Does the N014 pin output of the IC04 maintain "High"?
When either of the indoor units (B & C) is turned on.
(3) Does the N014 pin output of the IC04 maintain "Low"?
When both of the indoor units (B & C) is turned on.
Does the No7 pin output of the IC04 maintain "Low"?
Are the Q901, and 904 in "Turn-off" condition?
Are the Q902, Q903 and Q905 in "Turn-on" condition?
Does the operation of the Q701 lead to
activation of the compressor relay (RY71)?
Replace the "B" compressor.
Normal
Check and replace the relevant
IC (IC02, IC03).
• Check and replace the resistance
(R901, R928, R931) and diode (D907, D908).
• Check and replace the electrolytic condenser (C901)
(1) Is the NO3 pin voltage
of the IC04 DC5V?
(2) Is the NO12 pin voltage
of the IC04 DC7V?
• Check and replace the
IC04.
• Check and replace the
resistance.
(R902, R903,R905, R906)
Is the No.5 pin voltage
of the IC04 DC5V?
Is the voltage at both
ends of the C903 DC10V?
Check and replace the
R911, D901, and C903.
Check and replace each transistor
Check and replace the Q701 and relay.
(Resistance at both ends of the relay: About 150)
Check and replace the
R913, R915 and IC04.
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
DB98_11868A(1)_1 3/3/03 11:17 AM Page 4-4