Malfunction Due To Noise; Checking Procedure For Pcb (Printed Circuit Board); Indoor Pcb (Printed Circuit Board) - Sanyo SPW-CR363GVH8 Service Manual

10. Malfunction due to Noise

Since communication control is performed by pulse signals, the unit is susceptible to external noise. The circuitry has
been designed in consideration of external noise and troubles should not occur in ordinary use. However, depending on
the installation conditions, there may be trouble caused by the noise.
High-frequency noise, etc. is superimposed on the signal wire and the signal pulses come abnormal, resulting in mal-
function.
Location easily subject to noise
1. Area with strong radio waves in the
vicinity of a broadcasting station.
2. In the vicinity of a radio station.
3. Location near a high-frequency sewing
machine or an arc welding machine.

11. Checking procedure for PCB (Printed Circuit Board)

The indoor PCB (Printed Circuit Board) have functions to check the signal transmission and reception of the serial circuit
and to check the microcomputer operation. (Self-diagnosis function)
Precautions required when checking
1. After turning off the power to the indoor unit, remove the inter-unit control wiring (U1-U2) and create a short-circuit
between U1 and U2.
2. Short the CHECK PIN on the PCB (Printed Circuit Board) of the indoor unit and turn on the power.
11-1. Checking the serial circuit
Indoor PCB (Printed Circuit Board) : A lighted LED indicates normal. A blinking LED indicates abnormal.
Outdoor PCB (Printed Circuit Board) : Blinking LEDs (D001 and D083) indicate normal. If one of the LEDs (D001 and
11-2. Checking microcomputer operation
When the microcomputer works normally, the relays are switched in sequence as below.

Indoor PCB (Printed Circuit Board)

Indoor fan Very high fan speed (HH) 0.5 seconds
Indoor fan High fan speed (H)
Indoor fan Low fan speed (L)
Indoor fan Very low fan speed (LL)
Drain pump
Operation order Operation signal
Alarm LED
Electronic expansion valve A
Electronic expansion valve B
Electronic expansion valve.A
Electronic expansion valve B
Symptom
1. Stops during operation.
2. Liquid crystal display flickers.
D083) goes off, it indicates abnormal.
Output ON time
0.5 seconds
0.5 seconds
0.5 seconds
0.5 seconds
0.5 seconds
0.5 seconds
0.5 seconds
0.5 seconds
0.5 seconds
0.5 seconds
III - 59
Service Procedures
Remedy
Treat the signal wire so that it will
not be influenced by noise.
↓
• Place the signal/wire away from
the generating source.
• Adopt the shielding wire.
SM830063
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