TB 9-6625-160-24
(11) On TI, set AMPTD to 150 mV. Adjust A4R85 (RMS OFFSET) for a reading on TI
right display that is same as V ac reading on MULTIMETER (within 0.5 mV). If A4R85 does not
have sufficient range, add or alter A4R143 or A4R144 as follows in (a) through (f) below:
(a) Unsolder A4R143 or A4R144 if present.
(b) With MULTIMETER set to V dc, measure voltage at junction of A4R72 and
A4C46.
(c) If voltage (ignoring polarity) is greater than 2 mV, compute R=1500/V, where
V is voltage measured (in volts).
(d) Select a resistor which has a standard value resistance nearest R. If measured
voltage was negative, solder resistor in location for A4R143; if positive, for A4R144.
(e) After a five-minute warm up, measure voltage again which should be
between 2 and +2 mV dc.
(f) Repeat adjustment of A4R85.
(12)On TI, set AMPTD to 3 V. Repeat technique of (10) through (12) above until right
display of TI and MULTIMETER readings are same within limits stated for both 3 V and 150 mV.
(13) On TI, key in 5.2 SPCL to select averaging detector. Set AMPTD to 3 V.
(14) Adjust A4R93 (AVG SCALE) for a reading on TI right display that is same as
reading on MULTIMETER (within 1mV).
(15) Set AMPTD to 150 mV. Adjust A4R149 (AVG OFFSET) for a reading on TI
right display that is same as reading on MULTIMETER (within 0.5 mV).
(16) Set AMPTD to 3 V. Repeat technique of (14) through (16) above until TI right
display and MULTIMETER are same (within limits stated for both 3 V and 150 mV).
(17) Key in 5.7 SPCL to select quasi-peak detector.
(18) Adjust A4R207 (QUASI-PEAK) for a reading on TI right display that is same as
reading on MULTIMETER (within l mV).
e. Sinad Meter Adjustment
(1) Press TI numerical key for 41.0 and then SPCL key to initialize TI.
(2) Set TI INPUT and OUTPUT FLOAT switches to ground.
(3) Key in 16.1 SPCL to set SINAD resolution to 0.01 dB.
(4) Connect TI OUTPUT HIGH to INPUT HIGH.
(5) Adjust mechanical zero adjustment screw on panel meter cw for a zero meter
reading, then turn screw slightly ccw to free mechanism from adjusting peg.
(6) Set AMPTD to 3 V and MEASUREMENT to SINAD. Key in 7.1 SPCL to
enable 24 dB SINAD meter range. Key in 6.1 SPCL to hold notch filter.
(7) Set FREQ to 890 Hz. Fine adjust source frequency to obtain a reading on right
display between 12 and 18 dB.
(8) Adjust A4R142 (METER CAL) so that panel meter reads same as right display.
(1) Press TI numerical key for 41.0 and then SPCL key to initialize TI.
(2) Set TI INPUT and OUTPUT FLOAT switches to ground.
(3) Connect MULTIMETER to OUTPUT connector on TI.
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