Wattmeter Calibration; Input Swr Adjustment - Pride Amp Series Service Manual

Pride DX300 CHAPTER 4

4.2 Wattmeter Calibration:

The following adjustment is from the factory manual you may want to do it bypassing the safety interlock and
adjust it with the top removed but use caution.
If adjustment becomes necessary, it should be performed only if the following equipment is available:
Exciter: 100 to 200watts output at 28 MHz
Dummy load: 50ohm with an accurately calibrated wattmeter.
Calibration procedure:
1) Remove the top cover after allowing several minutes for the unit to discharge to a safe level.
2) Disconnect the right hand (as viewed from the front of the unit) coax cable at the wattmeter board and attach
a short length of RG58/U coax cable from the wattmeter board to the output of your exciter.
3) Disconnect the left hand coax cable and attach a short length of RG58/U from the wattmeter board to the
input of the dummy load/wattmeter.
4) Apply power and adjust the exciter for an output of 100 to 200watts as read on the dummy load/wattmeter.
5) Set the potentiometer on the wattmeter board for the same reading.
This now completes the calibration of the wattmeter. Restore the unit to its original configuration.

4.3 Input SWR adjustment:

If the input SWR should require adjustment on any particular band, the following procedure should be used:
1) Remove the bottom cover after allowing sufficient time for the power supply to discharge to a safe level.
2) Apply +12 VDC to point (B) as identified on the pictorial of the main circuit board.
Figure 4-3 Jumper B
3) Place the TUNE/STANDBY/OPERATE switch into the operate position.
4) Apply approximately three watts of drive to the input of the amplifier (with band switch set to the appropriate
band).
5) Spread or compress the turns of the toroid for the band in use to obtain the lowest SWR reading possible.
6) Restore the unit to its original configuration.
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