Vectronics VEC-1002K - Manual (Page 19)

VEC-1002K Owner's Manual 2 Meter FM Receiver Kit
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extreme care during insertion, and move slowly. It's very easy to miss a socket
opening and fold a pin underneath the body of the IC.
! ! 3. Find U2, a MC34119 8-pin gated audio amplifier IC. Position the
keyed (or notched) end of U2 toward the left side of the board, so it
coincides with the key in the socket. Install, checking carefully that all
8 pins enter their respective socket openings.
! ! 4. Repeat the above procedure with U1, the MC13135 24-pin NBFM
dual-conversion receiver IC. The keyed end of this chip also goes
toward the left-hand side of the board, matching the key on the socket.
Install and check pin insertion carefully.
This concludes the construction phase of your receiver. You deserve a break!
When you come back, be ready to give your work a thorough "QC" quality
control check before moving on to the testing and alignment section.
TESTING AND ALIGNMENT
PC Board Inspection:
Even the most experienced builders make mistakes! Before applying power to
your kit, give it a thorough QC (quality control) inspection. This will help you
find inadvertent assembly errors that might prevent the radio from working or
cause damage to sensitive parts. Follow this procedure:
! Compare parts locations against the parts-placement diagram. Was each
part installed where it is supposed to be? Was the correct value used? Start
at one side of the board and work your way across in an organized pattern.
! Inspect the solder side of the board for cold-solder joints and solder bridges
between tracks or pads. Use a magnifying glass to obtain a clear view of the
track area. If you suspect a solder bridge, hold the board in front of a bright
light for a better view. All joints should be smooth and shiny, indicating
good solder wetting and flow. Resolder any beaded or dull-appearing
connections.
! Finally, check all electrolytic capacitors and diodes for correct polarity.
Does the plus (+) polarity symbol on the part agree with the pictorial and
with the silk-screen pattern on the PC board? Is the banded end of each
diode positioned correctly? Also, were your ICs installed so the dot or
notch on the plastic case corresponds with the white dot or marking on the
PC board? Was Q1 installed correctly?
Be sure to correct all errors before moving on. If a careful inspection revealed
that everything is A-OK, you're now ready for the moment of truth!