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2.5 Install 1N4007 diodes

Install the six 1N4007 diodes D1-D6. 

Pay attention to the orientation of the diodes which is critically important. The diodes have a black 
body and a white stripe. The white stripe end must be aligned with the white stripe on the image 
on the PCB silkscreen. In the diagram below, all the white strip ends of the diodes are on the left 
of each diode position. 

So far, the assembly should
look like this → 

QDX assembly Rev 1.00

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Summary of Contents for QDX

Page 1: ...QDX QDX QRP Labs Digital Xcvr transceiver Assembly design and operating manual QDX assembly Rev 1 00 1...

Page 2: ...zed local oscillator 47 4 4 Solid state transmit receive switch 50 4 5 Switched receiver band pass filter 51 4 6 Double balanced Quadrature Sampling Detector 52 4 7 Low noise pre amplifiers 53 4 8 Dig...

Page 3: ...n suite of configuration and analysis tools Lifetime free firmware upgrades with QRP Labs Firmware Update QFU bootloader for easy firmware update on any OS with no extra software or drivers or program...

Page 4: ...manual Remember this when you come to the assembly step for preparing and installing the output transformer T1 The primary is still 3 turns with a tap half way at 1 5 turns The secondary no tap will n...

Page 5: ...components so it is much better to get them correctly installed the first time In the event of a mistake it is always best to detect and correct any errors as early as possible immediately after sold...

Page 6: ...QDX assembly Rev 1 00 6...

Page 7: ...QDX assembly Rev 1 00 7...

Page 8: ...QDX assembly Rev 1 00 8...

Page 9: ...10 11 12 13 14 17 18 26 27 29 3 100K SMD R15 16 19 3 470K SMD R7 8 9 Capacitors 50V Multi layer Ceramic capacitors Qty Value Description Component numbers 1 22pF Label 220 C29 1 30pF Label 300 C31 2 4...

Page 10: ...SMD BC857 PNP T3 1 SMD BC817 NPN T4 1 SMD Red LED DIAG 1 3mm Red LED PANEL Inductors Qty Description Component numbers 6 SMD 47uH L11 13 15 16 17 18 4 47uH radial inductor L1 5 7 9 replace SMD induct...

Page 11: ...33 mm diameter wire AWG 28 1 50 cm 0 60 mm diameter wire AWG 22 1 M3 12mm Steel 12mm long M3 screw 1 M3 Steel M3 nut 1 M3 12mm Steel 12mm diameter M3 washer Enclosure OPTIONAL Qty Value Description 2...

Page 12: ...2 3 Inventory parts QDX assembly Rev 1 00 12...

Page 13: ...r body which is coloured yellow The actual value e g 220pF is written in red text next to the capacitor Note that the leads of the 56pF capacitor 56J need to be bent to fit the 2 5mm holes Qty Value D...

Page 14: ...cally important The diodes have a black body and a white stripe The white stripe end must be aligned with the white stripe on the image on the PCB silkscreen In the diagram below all the white strip e...

Page 15: ...nsistors in the positions shown with their flat faces flush against the PCB Use the 12mm M3 bolt washer and nut to firmly press the transistor faces against the PCB as shown Refer to the diagram and p...

Page 16: ...leads soldered in step 3 2 Solder them in the positions shown soldering on the bottom side of the board Photo below left Next slide the TCXO module onto the wires and lower it to sit flat on the main...

Page 17: ...up back at the end where it started Assembly of this transformer is best done in steps as follows Please read all the steps before commencing the assembly Step 1 Carefully unwrap the thick 0 6mm AWG 2...

Page 18: ...the wire coming out of the bottom left hole as shown cut it to about 1cm protrusion Step 6 Squeeze together the center tap to try to avoid subsequent confusion Step 7 Start the 3 turn secondary windi...

Page 19: ...ring iron to the wire until the enamel burns off But that doesn t work so well on thicker wire such as this So my technique here is to scrape the enamel off at least partially using wire cutters The c...

Page 20: ...oint for maybe 15 seconds to really be sure of a good joint and burning away any remaining enamel Step 16 Check that none of the wires protrude more than 2mm from the surface of the PCB since if you a...

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