Haier U Series Service Manual page 80

A
Check the status of LED1 on
the indoor mainboard. If the
LED1 blinks interruptedly
No
Test the outdoor power supply
(230VAC and +310VDC) with a
multimeter.
If both 230VAC and 310DC
are available,measure IC11
+12V(from7805) is available.
YES
measure +5V(from7805) is
available.
YES
If the LED1 is off within two minutes
after the machine is supplied with
power, 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.
If 230VAC is available but
310DC not, the power module is
damaged, replace it with a new
one.
NO
The IPM module is damaged;
Replace them with a new one
The outdoor mainboard is damaged;
NO
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
Yes
measure the voltage between Jumpers
3 and 4 of IC7 on the indoor
mainboard with a multimeter.
If the voltage is of a
constant value of 0V
NO
The indoor mainboard is
damaged; replace it with
a new one.
Yes
Domestic Air Conditioner