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SERVICING
CONTACT CLEANING
GEH-2030
For cleaning fine silver contacts, a flexible burnishing tool should be used. This consists of a
flexible strip of metal with an etched roughened surface, resembling in effect a superfine file. The
polishing action is so delicate that no scratches are left, yet corroded material will be rew.oved rapidly
and thoroughly.
lhe flexibility of the tool insures the cleaning of the actual points of contact.
Fine silver contacts should not be cleaned with knives. files or abrasive paper or cloth. Knives or
files may leave scratches which increase arcing and deterioration of the contacts. Abrasive paper or cloth
may leave minute particles of insulating abrasive material in the contacts, thus preventing closing.
The burnishing tool described above can be obtained at the factory.
MECHANICAL ADJUSTMENTS
The relays are adjusted at the factory and it is advisable not to disturb the adjustments.
If for
any reason they have been disturbed, the following points should be observed in restoring them.
Refer
~o
Figures 1, 2. 3 and 14 for the location of the parts mentioned.
CAUTION: When the time scale is rotated manually it should only be turned far enough so the inner
cam clears its contact brush.
1.
The gap between the contact tips on each set of the timing unit contacts should be approximately
1/16 inch. Each contact brush should bear against its respective scraper brush.
2.
When rotated, the insulated cams should touch the inner contact brush at the "V" only, but high enough
I
on the "V" to insure 1/64 inch wipe on the outer contact brush. These cams should not extend beyond
the edge of their respective contact brush.
3.
With the pointer of the rear insulated cam set at maximum time setting on the scale, this cam should
rotate far enough beyond the apex of the "V" in the contact brush to allow the contacts to reopen
when the timing unit is fully operated.
.
4.
There should be at least 1/32 inch clearance between the time scale assembly and the front mounting
plate.
5.
There should be no binding between the gear on the main shaft and the pinion on the magnetic damping
element shaft.
6.
The pawl of the ratchet assembly on the magnetic damping element shaft should remain engaged to the
same tooth when the time scale is rotated from zero to the maximUM time setting mark and should allow
the gear to slip when the scale is released.
7.
The flexible stop arm at the rear of the main shaft should clear the supporting bracket by at least
1/32 inch.
8.
With the operating magnet in either the de-energized or the fully operated position, the driving arm
should clear the cutout section of the main shaft supporting bracket by at least'1/32 inch.
9.
The driving arm assembly should clear the rear mounting plate by at least 1/32 inch.
10. There should be at least 1/64 inch clearance between the reset spring collet and the rear bearing
of the rotonoid.
11. The time of operation for any scale setting may be varied by sliding the copper cylinder forward
or backward on its shaft or turning the driving spring collet on its shaft. Be sure to tighten
the set screw after adjustments have been made.
12. With the rotonoid de-energized. the reset spring is prewound approximately one-half revolution and
the driving spring is prewound approximately three-fourths of a turn.
13. The gap of all TX and TV unit contacts should be at least 1/64 inch.
14. The wipe of all TX and TV unit contacts should be approximately 0.006 inch.
7
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