Ramsey Electronics QAMP20, Assembly And Instruction Manual

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QAMP20 • 8
ˆ 15. Install Q3 and Q4, 2N3904 NPN transistors, observing proper
orientation of the flat side. These two transistors amplify the signal
diode's output to a level high enough to close relay K1.
ˆ 16. Install diode D4, 1N4002 style black epoxy diode. Check positioning of
the banded end.
ˆ 17. Install jumper JMP2. Use a piece of scrap component lead wire bent
into a "staple" shape and inserted into the board like a component.
Jumpers act as electronic "bridges" carrying signals over PC board
circuit traces underneath.
ˆ 18. Install C13, .1 µf disc capacitor (marked .1 or 104).
ˆ 19. Install L4, 10 µH inductor (green body with brown-black-black bands).
ˆ 20. Install R3, 10 K ohm resistor (brown-black-orange).
ˆ 21. Install C2, 10 µf electrolytic capacitor. Electrolytic capacitors are
polarized with a ( + ) and a ( - ) lead and must be installed correctly for
proper operation. Generally, capacitors have their ( - ) lead marked
with a black stripe while PC boards have the ( + ) hole indicated.
ˆ 22. Install D1, 6.2 volt Zener diode (gray body with a black band). This
diode provides a stable voltage which is used to provide bias for the
power transistors.
ˆ
23. Install R5, 1 K ohm resistor (brown-black-red).
ˆ 24. Install R2, 6.8 K ohm resistor (blue-gray-red).
ˆ 25. Install R1, 1 K ohm resistor (brown-black-red).
ˆ 26. Locate another 1 K ohm resistor (brown-black-red). Trim back one lead
to a length of ¼ inch. Bend this wire into a small loop as shown. This
loop will act as a convenient point to connect a test probe for setting
the bias voltage. Insert the resistor into the PC board and hold it
carefully while you solder it to the board.
ˆ 27. Install R8, 270 ohm resistor (red-violet-brown).
ˆ 28. Install C11, .001 µf disc capacitor (marked .001 or 102).
ˆ 29. Install R9, another 270 ohm resistor (red-violet-brown).
ˆ 30. Install C12, another .001 µf disc capacitor (marked .001 or 102).
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31. Install C8, .1 µf disc capacitor (marked .1 or 104).