MXD5U OPERATIONS AND MAINTENANCE
E18
Direct Vswr Relay reset from the Remote Reset Command
This jumper allows the Remote Reset Command to directly clear the VSWR trip relay
Setting = Installed for all MXD5U transmitters
E19
Forward Power Detection Type
Setting = PK for all MXD5U transmitters
2.2 P
OWER
C
ALIBRATION
,
AGC
AND
C
UTBACK
S
ETUP
HIGH VOLTAGE
RISK OF EXPOSURE TO VOLTAGES UP TO 260VAC
Use particular caution near the power supply’s transformer terminals.
The following setup is for the overall assembly of the MXD5U transmitter. It assumes that all individual
components in the assembly have been tested and biased, including the Control Board, the Amplifier Boards and
the Directional Coupler.
Note that the tests below are factory specific and therefore do not include the use of an Output Mask Filter. If one
is available, it can be inserted and setup performed as described in the procedure,
with the following exceptions
.
-
perform power calibration at the filter output calibrating to a 5W level
-
installation and alterations of test loads are done at the filter output, not transmitter RF Output.
PLEASE NOTE SAFETY WARNING ABOVE.
Connect a jumper wire across the terminals of the INT’K (External Interlock) terminal block at the rear panel. This
is temporary and must be removed when tests are completed.
Confirm Amplifier Bias
Terminate RF Out with 50R (min 20W rating). Apply no rf drive.
Turn ON Amplifier at front panel. Check for 28VDC at Amplifiers.
Check Amplifier Bias Currents: Front End Amplifier: 0.2-0.3A, IPA:1A, Amplifier Pallet: 1.0A
Power Calibration
Set R105 completely CCW. Ensure J8 is connected.
Remove all Control board jumpers
except
;
-
E7 and E8 IN
-
E2 to RS232
Monitor TP1. Adjust R39 for 0.02VDC.
Apply signal to get full power + filter losses at output. Approx 6W.
Check out-of-band shoulder levels at 6W for the broadcast channel before proceeding.
Set E5 to get 4-8V at TP1. Monitor TP2; adjust R46 for 4.00V.
Adjust R79 for 100% meter reading.
Increase Power to get 110%. Remove E7 and set R73 to get 4.0V on TP3. Meter should again read 100%.
PUB09-03 Rev 0 April 16, 2009
09-03-4
MXD5U Operations and Maintenance
