Receive a frequency with FM
mode, in tune mode. (Tune
mode turns on digital
decode.)
Is voltage
okay on IC313-pin 2 (3.3 V), and
IC313-pin 29 (1.8 V).
Is receive
audio present on IC313
pin 19?
Are square
waves on IC313 pins 4, 5,
6, and 28?
Defective IC309, or LC305.
Defective IC8, R339, C407
and/or associated circuit.
If IC313 pin 24 is high (3.3V),
and pin 25 has a 10s of MHz
sine wave, defective IC313
and/or associated circuit.
Is digital
audio (voice) on IC313
pin 10 when recieving
IMBE?
Defective IC8, IC9, IC11,
speaker, and/or associated
circuit.
Also check that IC310 pin 27
goes low when receiving
IMBE, and IC307 pin 69 goes
high when receivng IMBE.
Defective IC313.
NO
NO
NO
NO
YES
YES
YES
YES
DSP Section (Digital Audio, etc.)
14
Summary of Contents for PRO-197
Page 15: ...PRINTED CIRCUIT BOARD Main PCB Top View 15 ...
Page 16: ...Bottom View 16 ...
Page 19: ...19 ...
Page 20: ...WIRING DIAGRAM 20 ...
Page 73: ......
Page 74: ......
Page 75: ...RadioShack Corporation Fort Worth Texas 76102 08A08 ...