is in the cable (or the geophone if you haven’t
eliminated that). If the bad channel does not move
in the prior test, try reversing the output cable to
the seismograph. If the bad channel still doesn’t
move, then the problem is in the Seismograph.
If you have isolated the problem to the rollalong
switch (or the adaptor cables), notice whether the
bad channel moves when you change the switch
position. If it moves, the problem is on the input
side. If the problem channel does not move, the
problem is on the output side or output cable.
Remember that the last geophone in the array is
not used until after you relocate the seismograph
and rollalong switch for the next series. When you
lose or break a geophone, you can omit this one
from the survey.
Take note of the gap adjustment warning on the
front page.
There are a number of adjustments to synchronize
the switches and indicators. These will not normally
be required unless the switch is disassembled for
service, or if the knob is forced at the stop.
On Model RS-96/24, the only adjustments required
are the positions of the indicator dial and of the
detent. Open the case by removing the screws from
the sides. Examine the rotating switch mechanism
and locate the contact pins, Notice that the station-
ary part of the switch (called the stator) has four
50-pin connectors which are coupled to the inputs
by flat cables. Looking at the top, the inputs are or-
ganized as follows:
Stations
49-72
Stations
73-96
Stations
25/48
Stations
1-24
Turn the switch so the contacts are centered at the
3 o’clock position over stalions l-24.
Look carefully under the pins and see that the con-
tacts are centered on the station l-24 pads on the
stator circuit board. This corresponds to position 1
on the dial.
Loosen the two Allen screws on the large red gear.
Turn the dial until the “1” is under the cursor, and
re-tighten the set screws.
Check to see that the switch detents occur when the
contact pins are centered exactly over the pads. If
not, loosen the two set screws in the small red gear
and
adjust
its position. Re-tighten
the set screws.
On Model RS-120/48, there arc a
number of
synchronization adjustments.
Start by adjusting the dial cursor position as
described above.
When the upper rotor is rotated to the at the 3
o’clock position and the gap is set to “o”, the lower
rotor should be at the 6 o’clock position (conncct-
ing stations 25-48).
If not, loosen the set screws on the center small
gear on the side. Position the
IWO
stalors (lop over
stations l-24 and bottom over stations 25-48) so the
pins are exactly over the center of the contact pads.
Ignore the gap indicator knob. Tighten the set
screws.
Without moving the rotors, adjust the large knob so
that the line for gap 6 is vertical when in position 1.
Adjust the gap knob to position “0”.
Geostuff
RS-96124 & RS- 120/48
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