Tektronix 1502C User Manual page 107

Appendix C: Operator Troubleshooting
Meanings:
Remedies:
C–6
errors, which means that no measurements should be made with this instrument
before it is repaired.
The instrument searches for a point on the leading edge of the pulse that is on the
cable inside the instrument (about 10% up the pulse). This message indicates that
the search failed. This could be because the pulse is not there, or because the
sampler or gain circuitry is broken, or even because the timebase is not function-
ing properly.
The instrument must be sent to service for repair.
1502C MTDR User Manual