Ramsey Electronics HR40 - Manual (Page 19)

HR40
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19
TROUBLESHOOTING TIPS:
PROBLEM: ALL signals are chirpy and unstable.
SOLUTION: Sorry to have to say it , but this condition is only caused by a
weak battery! Use a fresh alkaline cell. Any strong signal
forces the audio circuit to rob voltage from the oscillator, which
causes the instability.
PROBLEM: Occasionally good but erratic operation.
SOLUTION: Check very carefully for a poor solder connection.
PROBLEM: Signals have an unpleasant hissing pitch.
SOLUTION: Try a different set of headphones, different speaker or external
audio amplifier. Some cheap headphones designed for casual
music listening have an undesirable filtering effect on CW
signals.
PROBLEM: Oscillator inoperative or wrong frequency.
SOLUTION: In addition to checking solder joints, be sure that L1 is
oriented correctly and that C1, C2, C3 and C4 are installed in
correct positions.
PROBLEM: Loud AC hum or buzz.
SOLUTION: If you are using the receiver with a battery or simply for listening
(i.e.: not connected to a transmitter or a AC power adapter),
these are likely causes of the AC hum:
•
No ground connection.
•
Receiver located too close to an AC device such as an older
electric clock, AC-powered radio, etc.
•
Antenna very close to a power cord or house wiring. If your
receiver is being used with a transmitter, the transmitter power
supply may be the source of the unwanted AC hum. If you are
using a 9-volt AC power adapter, the adapter design may not be
of sufficient quality for this application. Try a bypass capacitor, or
a different adapter or a well-designed and filtered DC power
supply.
A careful check of all construction WILL solve your problem. Over 95% of the
kits returned for repair have nothing more than a simple assembly or
construction error!