Ramsey Electronics FR220, Instruction Manual, Page: 24 / 28

FR-220
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24
FR-6 TROUBLESHOOTING GUIDE
The Ramsey FR-series FM receivers are among our most widely-used
and popular kits. The circuit itself, assembly and use are "cut-and-dried."
If your receiver does not work, there is an error in assembly or defective
part. Following is some help in case you experience difficulty.
Problem: Receiver completely "dead"- no sound at all.
❒
Check the following:First, the cable or plug adapter leading to
speaker or phones!
❒
Battery condition and battery wire polarity and soldering at S1
Connections associated with U3, the LM386 audio output IC
Problem: Receiver "hisses", but NO signals are heard, not even a
signal generator 2 inches away.
First, you need to verify that the local oscillator (SA602, L3, etc.) is
operating. Use another VHF receiver or a frequency counter to verify
oscillator operation. Next, make sure that the 10.245 MHz crystal
oscillator is running by tuning a general purpose HF ("shortwave")
receiver to that frequency. If either oscillator is not running, re-check
correctness of parts and solder joints associated with both oscillator
circuits. Further signal-path tracing may be necessary to find your
problem.
Problem: Very weak signals If Q1 is defective or incorrectly installed,
very little signal energy will reach the SA602.
If Q2 is defective or installed incorrectly, very little of the SA602's 10.7
MHz output is getting to the MC3359. Also, be sure L4 is peaked
correctly.
Problem: Considerable frequency drift or shifting
First, make sure that L3 is soldered securely to the PC board. If you plan
to use the receiver "on the go", you may wish to secure the base of the
coil to the board with reinforcing glue. If the receiver drifts, check all
wiring and components associated with AFC Q3 and pin 11 of the
MC3359.