TM 55-4920-390-13&P
1-8. RATE SETTING CHART. (See Fig. 1-6.) On the hinged inner lid appears a graph such that the 6perator, knowing
helicopter main rotor RPM and number of blades, can set the "Multi-turn Dial" on the back of the hand-held lamp and the
"Position" control on the bulkhead. A chart in the corner of this graph is treated so that the operator may write the
helicopter types with which he is working and the appropriate values for "Multi-turn Dial" and "Position". Thus, he is not
forced to refer to the graph after the first use. This information can be erased and re-written at will, using pencil or ball
point pen.
1-9. SPARE LAMP STORAGE. (See Fig. 1-1, b). A handy clip is provided on the cover of the electronics
compartment which will carry a spare flash tube in its plastic box. Instructions for replacement of flash tube age provided
in the plastic box and in Section 5-2 of this handbook.
NOTE
Always replace spare flash tube whenever previous spare has been used. This will avoid
annoying down time.
WARNING
The flash tubes contain gas under high pressure and are subject to breakage. This
constitutes an eye hazard so WEAR PROTECTIVE GLASSES whenever handling flash tubes.
1-10. SIZE. Size closed is 6-1/2" x 15-1/2" high; open for use is 13" x 15-1/2" x 6" high. Weight complete is 24 pounds.
1-11. THEORY OF OPERATION. Figure 1-7 is a simplified block diagram showing the relationship of the major Strobex
circuits. The schematic circuit diagram is shown in Figure 1-8. The following paragraphs, keyed to Figures 1-7 and 1-8
constitute a functional description of the Strobex Model 135M-9 circuits.
1-12. POWER SUPPLY. The Power Supply derives its energy from the aircraft's 28 VDC supply via the 40' power cable
fixed to the case. This is regulated to about 25 volts DC and then converted, in the transistorized inverter section, to high
frequency (prox. 2.5 KC) AC which is applied to the toroidal power transformer (T201) where the various required
voltages are generated, such as -
420 V, for charging discharge capacitors C 101, C 102 and C 103, Test Point A.
420 V, for SCR, Test Point 2.
13 V, for Amplifier and trigger circuits, Test Point D.
The above voltages are suitably rectified and filtered for their respective purposes.
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