TB 9-4920-469-24
12. Software Closed Box Adjustment (Model TT1200A)
NOTE
Perform this paragraph only if model TT1200A requires
adjustment.
NOTE
Paragraphs 12 a and 12 b are preparatory to performing the
model TT1200A software closed box calibration described in
paragraph c below.
a. Equipment Setup
(1) Set power supply to 9.0 V dc. Turn power supply off.
(2) Connect power supply to TI battery terminal (J1). Observe polarity (pin 2 of J1
is positive).
(3) Set TI controls as indicated in (a) through (f) below:
(a) POWER
OFF
(b) SYS RES
fully CCW
20Ω
RANGE
(c)
(d) TEMP ADJ
fully CCW
(e) FINE
fully CW
FUNCTION
IND TEST
(f)
b. Voltage Tests and Adjustments
NOTE
All test points are located on the main system PCB.
(1) Connect the multimeter, set to 2 kΩ, across R69.
(2) Adjust TI R61 to achieve a multimeter reading of 0.9668 kΩ.
(3) Disconnect multimeter from TI and turn Power Supply ON/OFF switch to ON.
(4) Turn TI PWR switch to ON.
(5) Press the TI C pushbutton to set TI to degree C mode.
(6) Set multimeter to 2 V dc (high impedance mode) and connect to TI TP13 (+) and
TP15 (AGND).
(7) Adjust R10 to achieve a multimeter reading of 1.1800 V dc (VREF).
(8) Connect multimeter to TI TP9 and TP15 (AGND).
(9) Adjust TI R15 to achieve multimeter reading of 0.4850 V dc (K1).
(10)Connect multimeter to TI TP12 and TP15 (AGND).
(11) Adjust TI R9 to achieve multimeter reading of 0.4843 V dc (K2).
(12)Adjust TI R3 to achieve TI display reading of approximately 50 C minimum.
(13)Adjust TI TEMP ADJUST fully CW and verify a TI display reading of greater
than 1400 C.
(14)Connect multimeter to TI TP16 and TP15 (AGND). Note multimeter reading.
