Tektronix 2236, Instruction Manual

Page: 100 / 350

Performance Check Procedure—2236 Service
12. Check Ohms
a. Select the S) function.
b. Connect one DMM test lead to the instrument and
short the tip to the other DMM input.
c. CHECK— Reading is less than .20 i).
d. Disconnect the test lead from the instrument.
e. Connect the ohms calibrator via a female-to-dual
banana adapter, a 50-i) cable, and a female-to-dual banana
adapter to the MULTIMETER INPUTS connector.
NOTE
The connection resistance must be less than 200 mfl.
Compensate for any measurement error in the 10-
and 100-0 checks by noting the reading obtained
when the calibrator output is shorted and adjust the
readings accordingly. Alternately, use the 4-wire sens­
ing capability of the calibrator to eliminate measure­
ment error.
f. CHECK— Reading is within the limits shown in Table
4-12 for each calibrator output resistance.
Table 4-12
Resistance Readout Checks
Calibrator
Display Readout
Resistance (ohm) Limits (ohm)
10 9.77 to 10.23
100 99.6 to 100.4
1 k .996 k to 1.004 k
10 k 9.96 k to 10.04 k
100 k 99.6 k to 100.4 k
1 M .996 M to 1.004 M
10 M 9.96 M to 10.04 M
g. Disconnect the test equipment from the instrument.
NOTE
The next two checks use two high-resistance preci­
sion resistors. To preserve the accuracy of these re­
sistors, store them in a dean, dry environment and do
not allow finger contact or other forms of contamina­
tion on the resistor body, if contamination is sus­
pected, wash the resistor body with isopropyl alcohol
and air dry. if exposed to excessive humidity, bake
the resistors at 200° F for 4 hours.
h. Connect the DMM test leads to the instrument; then
connect the 150 Mi) precision resistor to the test leads.
i. CHECK— Reading is between 148.4 Mi) and
151.6 MS).
j. Disconnect the 150 MS) resistor and connect the
1.5 GS) precision resistor to the test leads.
k. CHECK— Reading is between 1.34 GS) and 1.66 GS).
I. Disconnect the test equipment from the instrument.
13. Check Diode Forward Drop
a. Select UPPER FUNCTIONS and push in the FREQ,
PER, and WIDTH buttons simultaneously to enter the self­
test mode.
b. Push and release the SGL SWP button until S6 is
displayed.
c. Select the DCV function.
d. Set the Channel 1 Input Coupling switch to GND.
e. Connect the dc volts calibrator via a female-to-dual
banana adapter, a 50-S) cable, and a female-to-dual banana
adapter to the MULTIMETER INPUTS connector.
f. Set the calibrator to produce a 2.5-V output.
g. CHECK— Reading is Fd 2.474 V to 2.526 V.
h. Disconnect the test equipment from the instrument.
4-19