Troubleshooting Hints - Cobra CB 19 DX4 EU Service Manual

Cobra
Symptom
Unit does not work
at all
No output from
speaker at all
No noise on
speaker
Squelch does not
work
No modulation
LCD meter does
not work
LCD display does
not work
Channel selector
does not work
EMG CH9.19 does
not work
Model No: 19 DX4 EU

TROUBLESHOOTING HINTS

Possible Causes
• Defective power switch
• Blown fuse
• Broken DC power cord
• Defective components
• Defective external speaker jack
• Poor connection on microphone connector
• Defective push switch on microphone
• Defective internal speaker
• Defective VR1 and IC8
• Measure all the voltage of IC7 with voltage chart
• Defective squelch circuit components (RV5, VR2,
IC7)
• Defective VR2, RV5, IC3-D.
• Defective microphone.
• Poor audio output and defective IC3.
• Defective microphone connector components.
• Defective ALC circuit D8, D9
• Defective D11, D22
• Defective IC5.
• Defective RV2. RV6
• Defective RED wire fuse.
• Defective LCD module
• Defective IC5.
• Defective IC5.
Page: 5 / 13
Remedy Suggestions
• Replace defective components
• Replace defective components
• Replace defective components
• Replace defective components.
• Re-adjust Squelch sensitivity
• Replace defective components.
• Re-adjust Tx modulation
• Replace defective components.
• Re-adjust RX meter display
• Replace defective components.
• Replace defective components.
• Replace defective components.
Rev.: A
5