User manual
ASURO - 13
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4. Electronic assembly
Did you read the soldering instructions? Really? Well OK, let’s go!
4.1. Assembling the RS232 infrared-transceiver
•  IC1: Initially insert the 8-pole socket. The polarity mark of the (slightly asymmetrical) socket 
must correspond to the mark in the accompanying symbol on the PCB.
•  D1, D2, D3: 1N4148, pay attention to polarity! Read the imprints of the parts and take care 
not to interchange with ZPD5.1 or BZX55-C5V1!
•  D4: ZPD5.1 or BZX55-C5V1, pay attention to polarity! Read the imprints of the parts and 
take care not to interchange with 1N4148!
•  D5: SFH-415-U IR LED (Black LED) pay attention to polarity, press downwards to the PCB
•  C1: 100µF at least 16 volt, pay attention to polarity!
•  C2, C4: 100nF ceramic capacitor, imprint: 104
•  C3: 680pF ceramic capacitor, imprint: 681
•  Q1: BC547 (A,B or C) or BC548 (A,B or C)
•  R1, R5: 20kΩ_ (red, black, orange, gold)
•  R2: 4.7kΩ (yellow, violet, red, gold)
•  R3: 470Ω (yellow, violet, black, gold)
•  R6: 10kΩ (brown, black, orange, gold)
•  R7: 220Ω (red, red, brown, gold)
•  TR1: 10KΩ variable resistor
•  IC2: SFH5110-36 Infrared receiver IC, bend the legs with appropriate tongs! Pay attention 
to polarity (the curvature must be positioned to the outside)! Caution: electrostatic discharge 
(ESD) and excessive soldering or heating may damage the part!
•  X1: 9pol. SUB-D connector, case must be settled close to PCB. Attachment strips must be 
soldered as well!
•  IC1: insert the NE555P, pay attention to polarity!
Electronics
Finally check the board for short circuits or polarity errors. Check the soldering quality intensively 
and re-solder bad contacts. 
Ready!










