TM 55-4920-390-13&P
c) Setting the "Position" knob full CCW results in almost no time delay; the lamp flashes,
essentially, in coincidence with the input command. (This position is used for balancing in
conjunction with the Chadwick-Helmuth 170 series Balancers.)
1-15. COUNTDOWN CIRCUIT. In the event of a noisy signal, or one at a higher rate than the flash rate
capability of the Strobex, the countdown circuit automatically limits the flash rate to a rate acceptable to the
instrument. It effectively rejects commands in excess of the permissible rate. The countdown occurs between
50 and 70 flashes per second. This is an effective self-[protective device built into the Strobex Blade Tracker.
1-16. SCR CIRCUIT. During operation, SCR, Q12, conducts only after the turn-on signal from Q 11 is applied to the
SCR gate. When a signal is applied to the gate of the SCR, C 8 discharges through the primary of pulse transformer T
301 A very high voltage is then generated across the secondary of T 301 and at the trigger input to lamp V 301.
1-17. LAMP CIRCUIT. When the high voltage pulse from T 301 (approximately 10 kv) triggers the lamp, the xenon gas
in the lamp ionizes and becomes conductive. Capacitors C 101, C 102 and C 103 then discharge through V 301 creating
the light flash. When the voltage across V 301 falls close to zero, the gas in the lam-p de-ionizes (non-conductive) and
the discharge capacitors recharge. After C 8 recharges, the SCR (Q12) switches off and C8 recharges. This completes
a single light flash cycle. The flashes continue as long as the input pulses from the pickup and/or oscillator keep
triggering the SCR (Q12).
1-18. GAIN CIRCUIT. The Gain Circuit is a pot which attenuates in input signal. Its purpose is to allow the rejection of
unwanted inputs from Noise or magnetic objects on the rotating swash plate. (These unwanted pulses must be smaller in
amplitude than the desired pulse.)
1-11/(1-12 blank)