Kenwood TK-8100H Service Manual page 33

Transmitter Section
Item Condition
1. Frequency 1) CH : TX center
2) Transmit
2. Maximum 1) CH : TX high
power 2) Transmit
limitting
3. High 1) CH : TX low
power CH : TX low'
CH : TX center
CH : TX high'
CH : TX high
2) Transmit
4. Low 1) CH : TX low
power CH : TX low'
CH : TX center
CH : TX high'
CH : TX high
2) Transmit
5. DQT 1) CH : TX low (Wide)
balance CH : TC center (Wide/Narrow)
CH : TX high (Wide)
2) Transmit
6. MAX 1) CH : TX low (Wide)
balance CH : TC center (Wide/Narrow)
CH : TX high (Wide)
2) AG : 1kHz/50mV
3) Transmit
7. MIC 1) CH : TX center (Wide/Narrow)
sensitivity 2) AG : 1kHz/5mV
3) Transmit
8. DQT 1) CH : TX low (Wide)
deviation CH : TX center (Wide/Narrow)
CH : TX high (Wide)
2) Transmit
9. QT 1) CH : TX low (Wide)
deviation CH : TX center (Wide/Narrow)
CH : TX high (Wide)
2) Transmit
10. DTMF/MSK 1) CH : TX center (Wide/Narrow)
deviation 2) Transmit
If normal power is not obtained, please follow the
step below
Open the shielding cover (upper), and screw 3 locations
around ANT pin.
1. Switch off the transceiver.
Impedance of Final FET (Q504) and Drive FET (Q503) can
be measured easily using DVM Ω mode.
Normal condition – Gate : 20kΩ~50kΩ, Drain : 1MΩ~2MΩ
The above impedance values are rough estimations.
2. Switch on the transceiver. Check the voltage at F501 out-
put point.
The voltage is around 13.6V in receiving condition. The
voltage will be 12.6V~ in transmitting condition. If found
0V at this point then F501 is broken.
3. Remove R525.
ADJUSTMENT
Measurement
Test equipment Terminal
Frequency counter ANT
Power meter
Modulation analyzer
or Linear detector
(LPF : 3kHz)
Oscilloscope
Modulation analyzer ANT
or Linear detector MIC
(LPF : 15kHz)
Oscilloscope
AG
AF V.M
Modulation analyzer
or Linear detector
(LPF : 3kHz)
Oscilloscope
4. Connect 50Ω load at the ANT location.
Transmit and check current drain at High power mode.
If the current drain is less than 1A, then Final FET is bro-
ken.
If the current drain is less than 5.0A, short the Drive FET
gate to ground, and check the current drain.
If the current drain is not 0.1A less than the original value,
then the Drive FET is broken.
5. Check input power level at Drive FET gate location.
Connect the wire to [RF] location.
Transmit and check for power to be within the range of
0.7W~1W.
If power found is less than 0.5W, check the circuit before
the Drive FET.
TK-8100H
Adjustment
Parts Method
PC key Adjust to center frequency
VR1 48W
PC key 45W
25W
Adjust the waveform as below
± 4.0kHz (Wide)
± 2.0kHz (Narrow)
According to the large +, –
Check
± 0.75kHz (Wide)
± 0.35kHz (Narrow)
± 0.75kHz (Wide)
± 0.35kHz (Narrow)
± 3.0kHz (Wide)
± 1.5kHz (Narrow)
Specifications/
Remarks
Within ± 100Hz
± 1W
± 1.0W
± 1.0W
± 50Hz
± 3kHz± 0.2kHz
(Wide)
± 1.5kHz± 0.1kHz
(Narrow)
± 0.05kHz
± 0.05kHz
± 0.2kHz
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