Toshiba TLP510U, TLP511E, TLP510E, TLP511U manual Troubleshooting, Fluorescent does not turn on

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 (XC = 1/wc) of CI005 and CI006.

Before the fluorescent lamp turns on, the collector pulse of QI007 is 70 – 80 V(p-p). The v oltage is stepped up to 420 – 480 V(p-p) by L I002 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.

9-2. Troubleshooting

9-2-1. Fluorescent does not turn on

QI003 Collector voltage

Collector current

Fluorescent lamp voltage

Fluorescent lamp current

70kHz

31V

0 1.5A

0

Fig. 9-1-3

70 kHz

+30V

0V

– 80V

+0.16A

0

– 0.22A

Fig. 9-1-4

Fluorescent lamp does not turn on.

		Replace		OK
		fluorescent lamp.
			NG
						OK
		12V : between pins		NO
		5 and 7 of PM01.
			YES
	Higher than 10V.
		QI002 base.					Check power
							supply unit.
			Lower than 3V.
		Pulse higher than
Check fluorescent					NO
lamp ON/OFF SW		25 V(p-p) is developed at
(SM005)		QI003 collector.
and ARM SW.
			YES

Check secondary

side of LI002.

Check primary side of LI002.

Fig. 9-2-1

9-2