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2. troubleshooting -2, 2. troubleshooting – Toshiba TLP511E User Manual

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9-2

CI005 and CI006 are capacitors to stabilize the fluores-

cent lamp discharging current. After the discharging

starts, CI005 and CI006 limit the flow of the current

with the reactance (X

C

= 1/

w

c) of CI005 and CI006.

Before the fluorescent lamp turns on, the collector

pulse of QI007 is 70 – 80 V(p-p). The voltage is

stepped up to 420 – 480 V(p-p) by LI002 and applied to

the fluorescent lamp. When a filament is warmed, the

discharging starts and the collector voltage of QI003

becomes approx. 30 V(p-p). The fluorescent tube

voltage at turning on is approx. 120 V(p-p).

ARM SW works as a ON/OFF switch for the camera

power supply. When ARM SW turns on, the power is

supplied to the camera.

The waveforms of each section at operation is shown in

Figs. 9-1-3 and 9-1-4.

Fig. 9-1-3

Fig. 9-1-4

9-2. Troubleshooting

9-2-1. Fluorescent does not turn on

Fig. 9-2-1

31V

0

0

1.5A

QI003
Collector
voltage

Collector
current

70 kHz

+30V

– 80V

0V

– 0.22A

+0.16A

0

Fluorescent
lamp
voltage

Fluorescent
lamp
current

70 kHz

OK

OK

NO

NG

YES

NO

YES

Replace

fluorescent lamp.

Fluorescent lamp

does not turn on.

12V : between pins

5 and 7 of PM01.

QI002 base.

Pulse higher than

25 V(p-p) is developed at

QI003 collector.

Higher than 10V.

Check fluorescent

lamp ON/OFF SW

(SM005)

and ARM SW.

Lower than 3V.

Check secondary

side of LI002.

Check power

supply unit.

Check primary

side of LI002.

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