Tektronix TCP300 Series, User Manual

Page: 35 / 80

Control Summary
buttons, another degauss operation may be necessary to ensure accurate
measurements. Generally, if you change the DC offset by more than 5 divisions,
you should de-energize the circuit under test and perform another degauss routine.
Then, reenergize the circuit and take your measurements.
If the degauss operation has failed, and the AC and DC COUPLING LEDs are
alternately
fl ashing, this indicates the ampli fi er is displaying an error code with
the four status LEDs on the lower-left front panel.
(See page 43, Displaying Error Codes with the Probe Degauss Autobalance
Button .)
NOTE. The NOT TERMINATED INTO 50 Ω LED is on when the ampli fi er
output is not properly terminated into a 50 Ω load. Make sure your ampli fi er
OUTPUT is connected to an oscilloscope input using a 50 Ω BNC cable, and
that the oscilloscope input is set to 50 Ω impedance. Proper cabling is shown.
(See Figure 1 on page 1.)
If your oscilloscope does not have 50 Ω impedance settings for inputs, you can
place a 50 Ω feed-through termination on the oscilloscope input and connect
the ampli fi er output cable to the termination. Do not place the feed-through
termination at the ampli fi er end of the BNC connecting cable.
MANUAL BALANCE
Buttons and Indicator
The MANUAL BALANCE buttons allow you to fi ne-adjust the DC offset that
appears at the ampli fi er OUTPUT connector. The manual balance adjustment
only functions when the ampli fi er is set to DC coupling, and the MANUAL
BALANCE indicator is only lighted after you press one of the MANUAL
BALANCE buttons in DC coupling mode.
PROBE OPEN Indicator
When lit, this indicator informs you that the current probe is unlocked. You must
have the probe slide locked to degauss the probe or to accurately measure current.
OVERLOAD Indicator When this LED is red, it informs you that the measurement you are taking
exceeds the
continuous .
When this LED is orange, it indicates that the safe operating temperature of the
probe, and possibly the ampli
fi er, has been exceeded. Disconnect the probe from
the current source and allow time for the probe head and ampli fi er to cool.
When this LED blinks red and orange, it indicates that both the safe operating
temperature of the probe and the current limit have been exceeded.
WARNING. To avoid personal injury or equipment damage, do not exceed the
speci fi ed electrical limits of the TCPA300 and TCPA400 or any applicable
accessories.
TCPA300/400 Ampli fi ers and TCP300/400 Series Current Probes User Manual 17