19
Baker Instrument Company
The Measure of Quality
2.
Ensure that the test lead select switch is not positioned in the leads ground position.
3.
Check that the unit is supplied a proper ground.
4.
With a digital multimeter set to DC volts, check the voltage at J2 pin 5 on the Zero
Start Interlock board with the negative lead connected to chassis ground. This
measurement should be approxi13.5 volts DC and drop to about +12.7 volts
when the PTT button is depressed. If this voltage is not present or is low the fault can
be in the following circuits. The microswitch S1 which is mounted on the test lead
select switch can be open. Check Q5 base on the I/O board for +12.6 volts DC, if
present replace Q5.
5.
Check at Q4 base on the I/O board, this should be approximately .7 volts DC, if
present replace Q4.
6.
Check U8 pin 13 for a +5.5 volts DC, if measured low replace U7.
7.
Check U8 pin 12 also for a +5.5 volts DC, if at a low state check R13 and U9.
8.
Check at U8 pin 11 for low state, if at +5.5 volts DC, replace U8.
9.
Measure at J2 pin 2 on the Zero Start Interlock board, this measurement needs to be
+5.5 volts DC and change to approximately .4 volts DC when the PTT button is
depressed. If this is present check Q1 through Q5 and OC1, OC2, and OC3 for faults.
10.
Measure between R9 and KE2 pin 1, this coil voltage should change from –6.4 volts
DC to -.7 volts DC when the PTT button is depressed. If this is noted, replace K1
relay on the Zero Start Interlock board.
11.
If the measurement at step 9 is not present, check U15, U7, and R18 for defects,
replace if necessary.
PI
VALUE OR CURENT MEASUREMENT IS
INCONSISTENT
The digital series design tester will produce accurate results to a +/- 5% specifications.
The operators of the digital series may notice fluctuations in the current readings,
megohms values and PI data due to fluctuations in the input line power. Small variations
in the line power specifically at the one-minute and ten-minute intervals may cause
inconsistent readings even when the same windings are analyzed. To greatly improve
this occurrence, the steps below can be followed.
1.
The use of a Patriot line conditioner in series with the power to the tester will reduce
line fluctuations. Contact Baker Instrument Company for price and availability.
