VEC-1320K/1330K/1340K/1380K Owner's
Manual
32
may simply have poor transmitting antennas! You'll soon discover world-wide
QRP contacts are routine. A growing legion of CW operators have QRP-DXCC
certificates hanging on the wall to prove it!
IN CASE OF DIFFICULTY
Your VEC QRP-CW Transceiver has been thoroughly field-tested and is known
to be reliable and "forgiving" of construction errors. If you have difficulty with
your unit, the cause may be something as simple as a broken cable or a defective
power source. In most cases, you will be able to find the problem with some
organized troubleshooting. Begin your search with this checklist of symptoms
and remedies:
Does not power up:
Check the condition of your power source and connecting
cable. Also, check supply polarity, direction of D3, and inspect the fuse trace
near J1.
Does not key:
Check your key and plug. Also, check circuitry around Q4 for
construction errors. Make sure Y1 is installed correctly. Listen for off-air
signals in receive mode to confirm that Q1 is oscillating.
Weak Signal, no measurable output:
Check for construction errors. Also,
check polarity of D1 and D2. Vcc should be present on case of Q3.
Low Transmitter Output:
Check transmitter capacitor values against parts list,
and check number of turns on L4.
Severe chirp or motorboating on signal:
Check component values around Q1,
Q4. Check D1 and D2 for incorrect polarity or diode failure.
Transmitter remains on when unkeyed:
Check polarity of D1,D2. Also,
check Q4 and transmitter component values.
Receiver insensitive:
Check setting of R1, tuning of C1, antenna connections.
AM foreign broadcast interference:
Check resonant frequency of antenna,
station grounding, etc. Turn down R1. Overload by powerful AM shortwave
signals may be unavoidable with unidyne detectors under certain extremely-
strong signal conditions.
Audio Oscillation:
Check component values and capacitor polarity around U2.
Also, reduce receiver gain (R1) on extremely strong signals.
VXO cap fails to shift frequency:
Check L1, C16.
Blown Crowbar Fuse:
Usually caused by reverse power connection or by a
direct short circuit from Vcc to ground on the pc board. The etched copper fuse
