TCPA300/400 Amplifiers and TCP300/400 Series Current Probes Instruction Manual
7-21
Isolating Hardware Faults
Use the following procedures to help locate a hardware malfunction.
You can isolate the symptoms to the amplifier or probe by substituting a known
good probe or amplifier. If you suspect that you have a defective probe and you
don’t have another compatible probe, you can use the calibration adapter in place
of the probe to verify some of the amplifier functions.
Tables 7--3 and 7--4 list some of the failures that can occur with the amplifiers
and probes.
Table 7- 3:
Amplifier hardware faults
Symptom Possible cause Repair action
Amplifier does not power on. LEDs do not
turn on and fan does not work.
Internal power supply problem
Connector loose between main board and
front panel
Front panel is defective
Check for +15 V on power supply
connector J2, pin 1 at main board. If OK,
replace am plifier board. If not, replace
power supply.
Secure ribbon cable from front-panel
assembly to main board
Replace front-panel assem bly
LEDs do not turn on and fan works. Internal power supply problem
Connector loose between main board and
front panel
Front panel is defective
Check for +15 V on power supply
connector J2, pin 1 at main board. If OK,
check power suppl y test points on main
board: +5VD, +5VA, --5VA, +10V, --10V.
If these voltages check OK, replace the
front-panel assembly. If not, replace the
main board.
Secure ribbon cable from front-panel
assembly to main board
Replace front-panel assem bly
LEDs turn on and fan does not work. Defective fan or defective power supply Check for greater than +7V at fan
connector J3, pin 1 at main board. If
present, replace fan. If not, check for +15
V input f rom power supply. If +15 V is
present, replace the amplifier board. If
not, replace the power supply.
LEDs turn on in a random pattern
(different than is documented in this
manual)
Front panel is defective Replace front-panel assembly
One amplif ier range does not work, other
range is OK. (TCPA300 onl y)
Defective amplifier circuit Replace main board assembly
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