Installation, Operation and Service Manual
LKP Series
NOTES
1.) Low Readings: A very low amplifier output voltage may be normal for certain
channels; however, ripple can be as high as 3 V on a non-operating (full-off) channel.
Thus, a very low reading (i.e., 2 V to 3 V, should be suspected as a possible problem;
subsequent head movement or other magnetic change may show that the channel is
good. A blown channel fuse can cause a low reading.
2.) High Readings: The maximum allowable channel output of 40 V relates to the
maximum heat dissipation that the channel can safely handle. A reading of 30 V to 40 V
makes a change in head position highly desirable. A reading exceeding 40 V makes a
head position change necessary. A reading of 70-75 V indicates a full-on channel
condition, and requires immediate action to resolve the problem. A reading of 35-38 V
when immediately adjacent channels are significantly different may indicate that one of
the two SCRs in the channel has failed.
NOTE
You cannot get good ohmmeter readings if the head is on a live bus. The coils pick
up induced voltages from any rectifier ripple. The Hall plate resistance changes in a
high magnetic field.
© 2011 DynAmp, LLC
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