Haier HT-2180 Service Manual page 30

Pin Function
19 Vacant pin
20 Vacant pin
21 Grounding
22 Red primary color character
output
Reference Voltage(V)
Without With
signal signal
0 0
0 0
0 0
0 0
29
Circuit Explanation
Reference Resistance
Forward(Ω) Backward(Ω)
620 10000
620 10000
0 0
620 2200