Models SRJ-7 and HRJ-7 Juno Survey Meters

The 1.35 volt mercury cells (B-2) which supply the tube filament current,
will need to be replaced more frequently than the other batteries.
These cells must be replaced when it becomes impossible to zero the instrument
by means of both the external Zero control and the Internal Zero
control (accessible through a hole in the side of the case).
B. Alpha Screen Replaceaent
lChe Alpha screen, which covers the bottom of the chamber, is very
delicate.
If this .screen is touched, or allowed to touch a surface
being measured, it may be perforated or torn.
Replacement screens are available from Technical Associate6 and may
be easily replaced by following the procedure given below:
1.
2.
Remove the four nuts which form the feet of the instrument.
Remove the bottom plate and slide the two filters back to expose
the Alpha screen.
3.
Remove the two small screws on either side of the metal frame of
the Alpha screen.
The frame can now be slid towards the filters,
and out of the slot ;ihich retains one end of the frame.
4.
Slide the frame until it is out of the slot, then tilt it up
and remove by sliding towards the front of the instrument.
5*
The new Alpha screen can now be installed by reversing the
above procedure.
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