Huntron tracker 2000

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Period Measurement

Introduction to Test Equipment

Range Selection

Another logic circuit analysis technique is useful with the logic probe. This technique is to run the circuit under test at its normal clock (timing) rate while monitoring for various control signals, such as RESET, START, STOP, SHIFT, TRANSFER, or CLOCK. Questions such as "Is the counter operating?" are quickly resolved by noting if the probe indicator is flashing on and off, indicating that pulse train activity is present.

This ends our discussion on logic probes. Now, we'll study another piece of electronics test equipment that is used in evaluating integrated circuits, the HUNTRON TRACKER 2000.

HUNTRON TRACKER 2000

The logic probe we just discussed is but one specialized tool used to isolate problems to the component level. Another device you can use is the Huntron Tracker 2000. It is a very versatile electronic troubleshooting tool that is used to evaluate suspect components and/or locate defective components on de-energized circuit cards quickly and safely without requiring the removal of component leads. The unit provides a built-in display that allows you to visually analyze the component under test conditions.

Before connecting the Huntron Tracker 2000, you must first secure all power, then discharge all high-voltage capacitors.

PHYSICAL FEATURES

Because the Tracker 2000 has so many controls and indicators, it would impractical to cover each within this chapter. We will therefore concentrate our discussion only to the externally accessible features. To find information on internal controls and indicators, you should review the most current technical manual with up-to-date changes entered for the unit being used.

Front Panel

The front-panel (figure 5-18) design allows you to easily select the desired function. All the push buttons are the momentary action type and have light-emitting diode (LED) indicators embedded in them to show the functions that are active, by lighting up when active. A detailed description of each item on the front panel is provided in table 5-3 .

Figure 5-18. - Front Panel.

Table 5-3. - Front-Panel Controls and Connectors

NO.	NAME	DESCRIPTION
1	HORIZ control	When adjusted this controls the horizontal position of the CRT display.
2	VERT control	When adjusted, this controls the vertical position of the CRT display.
3	POWER on/off and INTENSITY control switch	When this is rotated clockwise, the power is turned on. Further adjustment of the switch controls the intensity of the CRT display. When it is rotated fully counterclockwise, the power is turned off.
4	TRACE ROTATE control	When adjusted, this controls the trace rotation of the CRT.
5	CRT display	This displays the signatures produced by the unit.
6	RANGE selectors	These are push buttons that are used to select one of four impedance ranges: LOW, MEDIUM 1, MEDIUM 2, and HIGH.
7	AUTO selector	This push button, when selected, initiates automatic scanning of the four ranges from low to high. The speed of the scanning is determined by the RATE control (item 14)
8	CHANNEL A selector	This push button, when selected, causes channel A to be displayed on the CRT.
9	CHANNEL A test plug	This is a fused test lead connector that is active when channel A is selected. All test lead connectors accept standard banana plugs.
10	ALT selector	When selected, this push button causes the unit to alternate between channel A and channel B. The speed of this is determined by the RATE control (item 14).
11	COM test plug	This test lead connector is the instrument common to and the common reference point for channel A and channel B.
12	CHANNEL B selector	This push button, when selected, causes channel B to be displayed on the CRT.
13	CHANNEL B test plug	This is a fused test lead connector that is active when channel B is selected.
14	RATE control	This controls the channel alteration and/or the range scanning.
15	G1 and G2 plugs	These are used for the pulse generator output test leads.
16	WIDTH control	This controls the duty cycle of the pulse generator.
17	LEVEL control	This controls the amplitude of the internal pulse generator.
18	PULSE GENERATOR selectors	These push buttons are used to select the output modes of the pulse generator: positive (+), negative (-) or PULSE/DC.
19	FREQUENCY selectors	These push buttons are used to select one of the three test signal frequencies: 50/60 Hz, 400 Hz, 2000 Hz.
20	HIGH LOCKOUT selector	This push button, when selected, activates the mode in which it is not possible to enter the high range either by manual or automatic range selection.

Cathode-Ray Tube (CRT) Display

The CRT display (figure 5-19) is used to view the signature of the component under test. The display has a graticule consisting of a horizontal and vertical axes. The horizontal axis is used to represent voltage with the vertical axis being used to represent current. The axes divide the display into four quadrants. Each quadrant displays a different portion of the signature for the component under test.

Figure 5-19. - CRT display.

Quadrant 1 displays positive voltage and positive current.
Quadrant 2 displays negative voltage and positive current.
Quadrant 3 displays negative voltage and negative current.
Quadrant 4 displays positive voltage and negative current.

Q.8 On the CRT display, what information is displayed in Quadrant 4?

The horizontal axis (see figure 5-19) is divided into eight equal divisions, allowing the technician to estimate the voltage at which changes occur in the signature for the component being tested. The associated approximate horizontal sensitivities for each range are:

High = 15.0 Volts/Div.
Medium 2 = 5.0 Volts/Div.
Medium 1 = 3.75 Volts/Div.
Low = 2.5 Volts/Div.

Back Panel

The back panel (figure 5-20) provides three additional controls and connectors. One is the accessory output connector (ACC), which provides a clock signal and power for the Huntron Switcher Model HSR410. Next, is the power cord connector used to provide the required ac line voltage used to power the unit. The last item found on the back panel is the FOCUS control; this controls the focus for the front-panel CRT display.

Figure 5-20. - Back panel.

OPERATION

The following sections explain how to use most of the front- and back-panel controls and connectors. Each control and connector has already been briefly described. To review this information, refer to figure 5-18 and table 5-3.

Initial Setup

First, turn the POWER/INTENSITY knob located on the front panel to the clockwise, on, position. Under normal conditions, the unit will come on with the following LEDs illuminated: power, channel A, 50/60 Hz, low range, and pulse/DC.

Focusing the CRT is very critical for the technician to be able to properly analyze the signature being displayed. This is done by first turning the INTENSITY control to a level comfortable for the eye, and then adjusting the FOCUS control (back panel) for the narrowest possible trace.

Aligning the trace will help determine, during troubleshooting, which quadrant the portion of the signature is in during a change. With a short circuit applied to channel A (connect a cable between jack A and COM), adjust the TRACE ROTATE control until the trace is as close to parallel as possible to the vertical axis. Then, adjust the HORIZ (horizontal) control until the vertical trace is as close to even with the vertical axis as possible.

Q.9 When aligning the trace with a short applied to channel A, which control should be adjusted to bring the trace parallel to the vertical axis?