Sinclair Alpha Inverter Series Manual page 52

Service Manual
(4) Malfunction of Zero-crossing Inspection Circuit Malfunction of the IDU Fan Motor U8
Main detection points:
Instant energization afte de-energization while the capacitordischarges slowly?
Malfunction diagnosis process:
Installation and Maintenance
Troubleshooting
for U8 malfunction
Turn power off
for 1minute,the
turn back on
U8 is still
displayed
Yes
The zero-cross detection
circuit of the mainboard is
defined abnormal.Replace
the mainboard with the same
model
End
The unit returns to normal.
Conclusion:U8 is displayed due
No
to power off/on while the
capacitor discharges slowly.
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