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DESCRIPTION
Operating the NO VCC switch alters the circuit so that there is no supply voltage. This puts
the supply voltage below the threshold allowed by the BFL. This is the reason why the VCC
pin indicates NOV+. To ensure the correct operation of the Training board a good comparison
is achieved when the condition being covered is applied. For this reason the red flag
indicates the pin where there is a difference when compared with the MASTER (Saved)
information.
COMMENTS
The threshold used by the BFL is 4.7V. When the connections test indicates NOV+ it could
either be No V+ present or V+ below allowed threshold. Both conditions should be
investigated further initially by switching off Connections test and using Voltage test in Loop
mode to verify the actual voltage present.
EXERCISE 8 : GROUND DETECTION
ACTION
Press START on IC Tester and observe GND indication on Pin 7.
Press NO GND switch and ensure LED lights.
DESCRIPTION
Operating the No GND switch alters the circuit so that the device Ground pin does not
present a valid ground to the tester.
COMMENT
In cases like this the first steps are to ensure the clip is connected/attached properly and
that the BFL supply is correctly referenced. If problem remains you must check the continuity
of the ground plane from the point of supply to the IC being tested. It may be that the PCB
has more than one Ground plane due to analogue and digital sections on the PCB.
EXERCISE 9 : AUTO CLIP POSITIONING
ACTION
Remove the clip from U5 and re-clip with opposite orientation. (red stripe to bottom of IC).
Press START on the IC Tester and observe results on IC diagram.
DESCRIPTION
This step shows the systems ability to automatically orientate the channels to match the
position of the clip on the IC. As long as all the pins on the IC are covered by the clip and the
connection to Vcc and GND is good the auto-clip function will operate.
The IC Diagram will remain in the same orientation.
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