Ramsey Electronics QAMP40, Assembly And Instruction Manual, Page: 7 / 20

QAMP-40 • 7
•
Insert the part, oriented correctly, into its correct holes in the PC
board. 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 J1 and 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, oriented with 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.