Vectronics VEC-830K - Manual (Page 14)

VEC-830K Instruction Manual Single Side-Band Filter Kit
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.
If you find a construction error and need to remove a part or two, it will be
easier if you have the right tools.
One very convenient item for freeing
soldered-in parts is a "solder sucker". This consists of a suction bulb or a
spring loaded vacuum pump that draws molten solder away from the pad and
lead. Alternatively, you may use a special copper braid called "solder wick"
(solder suckers and solder wick are both available at your local Radio Shack or
electronics supply house).
If you suspect you've damaged a
component during removal, better to replace it than risk reusing it!
Finally, rosin flux can absorb moisture, which may cause a problem for some
electronic equipment. To remove flux, use isopropyl alcohol (or 95% grain
alcohol) and an old toothbrush. Apply a generous amount of alcohol with the
toothbrush and scrub gently. Once the flux has fully dissolved, blot the bottom
of the board dry with an untreated tissue. Give it a final alcohol wash, and allow
to dry thoroughly.
CAUTION: ALCOHOL IS HIGHLY FLAMMABLE AND MUST BE USED
WITH ADEQUATE VENTILATION! USE SAFETY GOGGLES,
AND AVOID PROLONGED SKIN CONTACT. IT'S ALSO BEST
TO DO THIS OUTDOORS.
Now that assembly and inspection is completed, you're ready to begin the
testing and alignment phase of construction.
TESTING AND ALIGNMENT
The best way to test the VEC-830K is with a calibrated audio signal generator
and oscilloscope. However, the VEC-830K does not require any alignment. The
filter has three switch selectable selectivity cutoff points, Hi-Pass, 2.5kHz,
2.0kHz, and 1.5kHz. The switch positions on SW1 from left to right are HiPass,
2.5kHz, 2.0kHz, and 1.5kHz. The 1.5kHz hertz cutoff is the fourth switch
position from the left and is the narrowest filter cutoff, while the 2.5kHz cutoff
is the second position from the left and is the widest filter cutoff.
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