Troubleshooting; Precautions For Checking - Hitachi RAF-25NH4 Service Manual

ROUBLE SHOO ING
MODEL RAM-70QH4, RAM-80QH4
DANGER
1.
Remember that the
0V line is biased to
190V in reference to
the ground level.
2. Also note that it takes
about 10 minutes
until the voltages fall
after the power switch
is turned off.
DANGER
When using an oscillo-
scope, never ground it.
Don't forget that high
voltages as noted
above may apply to
the oscilloscope.

PRECAUTIONS FOR CHECKING

Power source
1 V, 50Hz
φ, 230
~
C1
Indoor
D1
unit1
C2
Indoor
D2
unit2
C3
Indoor
D3
unit3
C4
Indoor
D4
unit4
Outdoor unit P.W.B.
~
(0V)
b
⃝
MAIN P.W.B.
Across a b (0V line)
ー
Across b (0V line)
Always keep your hands
and metallic things away
from the enclosure of the
oscilloscope.
256
a
⃝
M
Compressor motor
approx 380V
..................
approx 190V
−ground............
DANGER!
Don't install
the ground
line.
Oscilloscope