The short locating procedure is the same as the last two examples. There is one additional step,
however, if you are using a Tracker 2000: select the 50/60 Hz test frequency. This makes the
impedance of the individual good capacitors as high as possible which minimizes the amount of
current diverted into the good components. If this diverted current is negligible the readings will
be 100% at points A, B, C and D. With no path beyond C4, it must be the faulty capacitor.
Conversely, if the diverted current is not negligible you may see the current readings go 100% -
98% - 95% - 93% at points A, B, C and D. This would still indicate that most of the current is
flowing in C4.
General Comments
When the reading drops to zero on a double-sided or multi-layered PCB, you need to check if the
signal died after passing a via or component pad. If it does, the current to the short is now
flowing on the other side of the board or in an inner layer. Turn the board over so that you can
continue to follow the trace or turn up the GAIN so you can follow the inner layer trace. When a
multilayer board has a short between the power and ground planes, the current "spreads out" and
since it is not concentrated in a PCB trace the magnetic field will probably be too weak for the
SHORTRACK to detect. Keep the leads from the Tracker connected to the PCB at points roughly
1 inch (25cm) apart. If you move the Tracker leads around to various points across the same
short, you may find a point where the SHORTRACK gives no response outside an area right
around the Tracker leads. In that case the fault must be within that area. In other words you may
not pick the best location for connecting the Tracker leads to the PCB the first time; moving the
Tracker leads around can be a normal part of short location.
MAINTENANCE
Repairs or servicing not covered in this manual should only be performed by qualified service
personnel as described in the HUNTRON SHORTRACK Model 90 Service Manual (contact
Huntron for availability).
General Maintenance
To clean the instrument, wipe the case with a damp cloth and mild detergent (do not use
abrasives or solvents) and avoid getting water inside the case. When the instrument is not in
use, store it indoors in a dry place.
Calibration
The SHORTRACK does not require periodic calibration for proper operation. There is a ZERO
adjust inside that is factory set to produce a 0 ohm +/-3 counts average reading with zero signal
(probe away from any AC magnetic field). This adjustment should not require any attention.
Battery Replacement
The instrument is powered by a single 9 Volt battery (NEDA 1604, 6F22 or 006P). Use the
following procedure to replace the battery:
1. Remove the current probe from the front panel receptacle.
2. The case bottom is secured to the case top by four screws. Using a #1 Phillips-head
screwdriver, remove the four screws from the case bottom and lift off the case bottom.
3. Lift the old battery out of the battery holder and insert a new battery into the battery holder.
4. Replace the case bottom and reinstall the four screws.
Probe Test
Use the following tests to verify the integrity of the current probe:
1. Continuity Test - measure the resistance between pins 1 and 3 of the probe jack. You should
read 16ohms +/- 20% if the electrical path through the inductor is intact.
2. Inductance Test - if you have access to a LCR meter, use it to measure the inductance
between pins 1 and 3 of the probe jack. You should read 220mH +/-20%.
