Ramsey Electronics SS70A manual

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done inside the chip, this should go fairly quickly.

ˆ32. Install C6, 22 pF disc capacitor (marked 22 or 22K).

ˆ33. Install C7, another 22 pF disc (marked 22 or 22K).

ˆ34. Install Y1, the 3.58 MHz or 10.24 MHz crystal. Make sure to mount the crystal in the proper holes.

ˆ35. Install R8, 1Meg ohm (brown-black-green).

ˆ36. Examine crystal Y1, if it is a 3.58 Mhz unit, install jumper JMP7, if your crystal is 10.24 Mhz, do not install JMP7. Due to a change in the PC board, the silkscreen may label this jumper as J3 or JMP7. This jumper (or lack of) tells the MX128 which crystal is being used.

ˆ37. Install U1, the MX128 16 pin DIP IC. Notice that one end of the chip is marked by a dot, notch, or band. This must be placed as shown in the parts diagram for proper operation. Gently insert all the pins through the circuit board, and solder. Be extra cautious as not to "bridge” solder between the pins, and don't worry about applying too much heat. Today’s IC's are very rugged and can handle the heat that any pen type soldering iron can deliver.

ˆ38. Install C1, 10 uF electrolytic. Be sure to orient the part correctly.

ˆ39. Install C9, 10 uF electrolytic, observe polarity.

ˆ40. Install R16, 10K ohm resistor (brown-black-orange).

ˆ41. Install jumper JMP1.

ˆ42. Install R15, 100K ohm resistor (brown-black-yellow).

ˆ43. Install C11, 100 pF disc capacitor (marked 100 or 101).

ˆ44. Install R10, 100K ohm resistor (brown-black-yellow).

ˆ45. Install R2, 100K ohm resistor (brown-black-yellow).

ˆ46. Install C2, 100 pF disc capacitor (marked 100 or 101).

ˆ47. Install R4, 100K ohm resistor (brown-black-yellow).

ˆ48. Install jumper JMP5.

ˆ49. Install jumper JMP6. You might notice that these last two jumpers go from ground to ground. A solid ground connection is crucial in all audio, digital, and RF circuits to prevent unwanted problems.

We’re almost there. The scrambling/descrambling portion of the circuit is done. The few remaining components comprise the power supply stage. Remember to follow along in the schematic and doublecheck your work as you go.

ˆ50. Install C17, a 1000 uF electrolytic capacitor. Be sure to orient it correctly as shown in the parts diagram.

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Contents Speech Scrambler Ramsey Transmitter Kits Speech Scrambler / Descrambler KIT SS70A Circuit Description IntroductionOSC Now, lets get building Resistors and Potentiometers SS70A Parts ListSS70A SS70A Assembly Instructions SS70A SS70A Congratulations Testing the SS70ATypical HOOK-UPS Configuring the SS70A inputsSS 70A Tape Recorder ConnectionLoop-through Audio Test What if I CAN’T Descramble Something I HEAR? Troubleshooting InstructionsConclusion SS70A Parts Layout Diagram Ramsey Kit Warranty Additional Suggested Items Estimated AssemblySpeech Scrambler SS70A Required Tools