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Problem:
Transmitter does not light up
·
Check Circuit Breaker on
back of unit
·
Check fuse
·
If front panel was not
functioning check ribbon cable connection
·
Check unregulated voltage
(white blue wire on voltage regulator)
·
Check (+) and (-) 12
volts. On voltage regulator board
-
Output of U705
Problem: RF
Power problem
·
Check unregulated voltage
- unit
makes power but output is low
·
Check that power out
matches front panel
·
Adjust RF level control on
front panel
- if
there is a “Flat Spot” on the RF level control turn control counter
clockwise to see where power starts to drop.
> Turn RF level control full clockwise
* Check RF Voltage at;
- Input
of Q900 our driver should be about 17 V P - P
-
Output at 40V P-P
Problem: No
Power no PADC
·
Check pre-driver U900
·
Check Driver Stage
-
Driver Bias FM30 = 3.5V at non RF side of R904
-
Driver Bias FM100 & 250 1.75V at non RF side of R904
- If
able to connect to a wattmeter
* FM30 >30 Watts
* FM100-250 10 Watts
·
Check PA Module
- Check
that RF is getting to Q1101 on PA
* Check our BNC on input board for RF shorts
·
PA DC Fault Flashing
- RF
Level full counter clockwise
- Open
low pass filter
-
Faulty Antenna
- R34
(power setting) full counter clockwise
- R12
Current limit is too low
* Measure at the board site of R13
>FM30 = 0.265VDC
>FM100 = 0.565VDC
>FM250 = 0.815VDC
>FM500 = 1.75VDC
Problem:
Audio
·
Put audio in 400Hz at
–12dBm left and right channel
·
Flow the audio through
FM30—27 watts
FM100- <50watts
FM250 < 197 watts
Max– Q900 could be bad.
Problem: No
Power no PADC
·
Load down the power
regulator
-
10-ohm—220 Watt Resister
- Turn
Carrier on and you should see PADC and PA amps
> If no voltage
* Replace U1, U2, Q801 and Q804
(all will have unregulated voltage
on them)
·
Check driver and voltage
on voltage regulator board 18-24 V DC
- No
voltage
> Check the cathode side of D2-703
* If no voltage replace
U801,802-Q801
·
No Voltage
- Check
Q704, base 18V transmitter 19 collector 19
To set up a
RF Meter Board
·
Turn on Carrier
·
Measure the outboard side
of R13
- Turn
current limit POT R12 to the following for:
> FM30 .265VDC
> FM100 .565VDC
> FM250 .815VDC
> FM500 1.75VDC
·
Adjust R67 SWR for 1.03 on
front panel
·
Turn carrier on
·
With a wattmeter in-line
adjust R34 power set to read
> FM30 33 watts
> FM100 110 watts
> FM250 275 watts
> FM500 550 watts
·
Adjust R72 power
calibration to read the same as the wattmeter
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