Toshiba FT-3809 BK Service Manual page 22

7. The voice of the caller can't be heard (incoming call).
Check the handset receiver
output.
OK
Check the handset RX
sensitivity.
OK
Check the base TX
power.
OK
Check the base TX
modulation sensitivity.
OK
Receiver of handset is
defective.
8. All keys of handset no function.
By using voltmeter, Check the
MCU-PWR of the handset.
OK
By using voltmeter, Check PIN
15 of HU11 of handset.
OK
Check the battery and battery
contact.
Check the RX IF circuit ( HU3 and surrounding circuit
NG
of HU3 ) and RX AF circuit ( HU7 and surrounding
circuit of HU7 )
Check the handset RX
NG
RF and mixer circuit
( around HQ1)
NG
Check the base TX circuit
using voltmeter.
NG
Check the base TX AF
circuit ( around PIN 1-12
of BU5 ).
NG
Check PIN15-28 of HU3 of handset
and surrounding circuit of U3.
NG
Check the HU3 and around circuit
of HU3.
21
OK
Receiver of handset is
defective.