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Construction of the RL-20 USB Radio Adapter Board

Top photo of the RL-20 PC board.
Click to enlarge.

Assembly:
If you purchased our kit, refer to the parts list and make sure you have all of the components you need to build the kit. All of the components are supplied with the kit, and while we make every effort to be sure we didn't omit any components, it can happen. If you are missing anything, or ruin something, just contact us.

Click here for Parts List.

Assembly can be done by personal choice, but you may find it easier to install the shortest components first, building toward the tallest, and finish with the connectors on the ends.

Install all resistors. Some resistors color bands may be hard to make out. If in doubt, use an ohm meter to verify the value before soldering it in place.

Install the diodes and shortest capacitors, observing polarity on all diodes and the polarized capacitors! The square pads are the banded end of the diodes and the + of the electrolytic capacitors. Small capacitors are identified as follows: "47" or "470" = 47pF, "104" = 0.1uF, in other words the first two digits are the value and the third digit (if present) is the number of zeros you add to determine the value. In addition, there are two components that you need to make sure you install correctly as they are polarized and installed opposite from one another - C3 and C5. The positives of the capacitors face one another - in other words, they go toward the center of the board. It's helpful to look at the photo above.

Install the crystal.

Then, install the 3 LEDs (short lead to the square hole).

Install the potentiometer.

Install the 1uF Tantalum capacitor (marked 105) with the printing on the side facing C19.

Next, install the transistor (flat to flat on silkscreen).

Next, install the larger capacitors.

Then, finish by installing the DB9F and USB "B" socket connector.

Information on the CM119A.
Click here to download a manual for the C-Media CM119A.

Email Kevin Custer for support.
 

Custom cables available from URI Cables. They will build a custom cable for the RL-20 for many radios.

 

Product of Masters Communications, all rights reserved.
Specifications may change without notice.
Images property of Kevin Custer - Masters Communications.
Board layout by Kevin Custer - W3KKC
HTML June 3 2020, W3KKC All Rights Reserved!