Ramsey Electronics QRP CW POWER AMPLIFIER KIT QAMP30 - Manual (Page 7)

QAMP-30 • 7
•
If helpful, gently bend the part’s wire leads or tabs to hold it in
place, with the body of the part snugly against the top side
(component side) of the PC board.
•
Solder all wires or pins of the part, whether the 2 wires of a resistor
or the 3 or 4 wires of a transistor.
•
Trim all excess wires extending beyond each solder connection,
taking care that wire trimmings do not become lodged in PC board
solder connections.
ˆ
1. Install S1, PC mount pushbutton switch. Solder all 6 pins securely.
ˆ 2. Install J1and J2, PC mount RCA phono jacks. Solder all 4 pins on each
securely as these connectors will be subjected to some stress when coax
cables are connected to them.
ˆ 3. Install J3, PC mount DC power jack.
ˆ 4. Install relay K1. Notice that it installs only one way.
ˆ 5. Install potentiometer R4. This pot allows adjustment of the bias to the
power transistors.
ˆ 6. Install C9, .01 µf disc capacitor (marked .01 or 103 or 10 nf).
ˆ 7. Install Q5, 221334 PNP transistor; orient the flat side toward D2.
ˆ 8. Install R6, 470 ohm resistor (yellow-violet-brown).
ˆ 9. Install R10, 51 ohm resistor (green-brown-black).
ˆ 10. Install R11, 2.2 K ohm resistor (red-red-red).
ˆ 11. Install R12, 10 K ohm resistor (brown-black-orange).
ˆ 12. Install D2 and D3, 1N4148 style signal diodes (glass body with black
band). Pay special attention to the banded ends. The banded end on a
diode is the cathode and must be oriented correctly or the circuit will not
work. Both diode D3 and diode D2 are detectors for sensing applied RF
power.
ˆ 13. Install C10, .1 µf disc capacitor (marked .1 or 104).
ˆ 14. Install R7, 100 K ohm resistor (brown-black-yellow).
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.