Technical Manual

10-27
Chart 25. 800 MHz No TX Deviation
Replace 20-pin
compression connector.
No TX Deviation
800MHz Transceiver
Audio at pin
14 of J1?
Set radio to test mode CSQ.
Connect radio to R4005B test box
or equivalent and inject a 1KHz
mic signal with amplitude
sufficient to provide 3KHz
deviation (about 11mV RMS).
PTT radio using external
PTT switch. Verify signals
per Figs. W8 and W10.
No
Yes
Check
continuity
between pin
14 of J1 and
pin 5 of U302.
No
No
MAEPF-26039-O
Yes
Yes
Audio at pin 5
of U302?
Audio at pin 30
of U302?
Replace U302.
Check components
C316,
C315,R305,C324,
and R314.
Chart 26. VHF/UHF No TX Deviation
No TX Deviation
VHF/UHF Transceiver
Audio at pin
14 of J1?
Set radio to test mode CSQ.
Connect radio to R4005B test box
or equivalent and inject a 1KHz
mic signal with amplitude
sufficient to provide 3KHz
deviation (about 11mV RMS).
PTT radio using external
PTT switch. Verify signals
per Figs. W8 and W10.
No
Yes
Audio &
voltage at
U204-5?
Check C303 &
continuity of
J1.
No
Replace U204.
No
Yes
Yes
Audio &
voltage at
U204-30?
Check
continuity of
J1.
Audio &
voltage
between C231
& C233?
Check solder
joint and for
broken runner.
Yes
No
Suspect R208.
VSF* at
R208?
Check U204.
Voltage
between R207
& R208?
*VSF = Voltage from Super Filter
(U204, pin 19) 4.6VDC.
Yes
No
Yes
No
Voltage at
CR202?
Audio between
R207 &
R208?
Yes
No
MAEPF-26040-O
C225 OK?
Suspect R207
or C231.
Replace C225.
Suspect
L218.
No
No
Yes
Yes