The first mechanism this investigation has established physically rather than
inferred. Brian pulled BE12599 and bench-tested it; a geophone swap settles it.
Same recorder, twenty minutes apart: Vert overswing 2026.0 with its own
geophone, 3.4 with BE9888's known-good one. Frequency 2.2 -> 7.4 Hz. All three
channels Passed, no offsets, no self-triggering, and a clean damped impulse with
broadband content. The recorder is functional and merely out of calibration.
A bench control -- trigger forced by slapping the microphone, geophone untouched
-- shows Vert producing 0.19 in/s of bipolar wander with no mechanical input at
all. The fault is continuous, not episodic. All three channels are affected:
Tran and Long sit on a small DC while their coils still pass the swing test,
Vert has lost damping entirely. That is leakage on several contacts plus one
gone open, not three elements failing in sequence.
The consequence that reaches past this unit: an autozero adjusts the RECORDER's
zero reference and cannot fix a geophone. If most offsets are geophone-assembly
faults, a re-zero succeeds only on the minority where the recorder really is at
fault -- which is exactly the ~10% rate recorded in section 5 and unexplained
since August. Procedure change: swap the geophone first.
Corrects 8e's title, which called it a connector rather than a geophone: the
swap narrows the fault to the assembly, and element / cable / connector remain
open within it. And reweights the cause -- the geophone is buried, not in the
enclosure with the nest, and the unit sat ~6 ft from I-80 WB, so road salt now
outranks the mice.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HgTe8CamXAHcAmaQ6QNcog
serversdownandClaude Opus 5
0a96a34b02