Haier 1U18FS2ERA Service Manual page 79

A
Check the indoor mainboard.
No
Test the outdoor power supply (230VAC
and +310VDC) with a multimeter.
If 230VAC is available but 310DC not,
the power module is damaged, replace it
with a new one.
If both 230VAC and 310DC are
available,measure +12V(from7805)
is available.
YES
measure the AC voltage between positions 1
and 3 on the terminal of outdoor unit with a
multimeter.
If the value varies between 0 and 80 VAC, the
outdoor mainboard is damaged, replace it
with a new one.
Yes
measure the voltage between Jumpers 3 and
4 of IC1 on the indoor mainboard with a
multimeter.
If the voltage is of a constant
value of 0V DCto5V DC
NO
The indoor mainboard is damaged; replace
it with a new one.
The outdoor mainboard is damaged;
Replace them with a new one.
If the value is constant at about 30V, the
indoor mainboard is damaged, replace it with
a new one.
The outdoor mainboard is damaged; replace
it with a new one.
77
Service Diagnosis
YES
Domestic Air Conditioner
NO