JVC 370 SC, 330, 340 SC service manual 22-30V depending on projector model

Chapter 2—Functional Descriptions

When the Arc Lamp supply first turns on, it supplies 170V to the ignitor. The ignitor then senses this voltage, activates it’s on-board supply, and produces a

1∝ S, 38KV pulse to the Arc Lamp. This pulse strikes an arc in the lamp. The Arc Lamp supply then provides the high current necessary to sustain the arc in the lamp. Refer to Figure 2-5 and the summary below for a description on the Arc Lamp and Ignitor timing.

/FANENBL

/ALENBL

/LAMPLIT

38 KV
170V
22-30V*
0V	1	2	5
		3	6	CPU TIME-OUT
		4		5-10 MINUTES

ARC LAMP ON	LAMP-OFF	FAN DISABLE
	COMMAND
IGNITOR FIRES
LAMP-ON COMMAND

*22-30V depending on projector model.

Figure 2-5Arc Lamp Ignitor Timing Diagram

Arc Lamp/Ignitor Timing Diagram Summary:

1.The operator powers Arc Lamp on. /ALENBL and /FANENBL from System Controller Board are pulled low. SPS receives /ALENBL from SCB and turns on the Arc Lamp PS.

2.Ignitor receives +170V boost voltage from the Arc Lamp PS.

3.Ignitor steps up the +170V boost voltage to a 1 ∝ sec pulse, approximately 38KV.

4.Arc Lamp ignites from the 38kV pulse.

5.High current (about 68-100A depending on projector model) begins through Arc Lamp and voltage drops to +22-30V (depending on projector model).

6./LAMPLIT signal goes to SCB to inform board that Arc Lamp is lit.

2-10 Model 330, 340SC, and 370SC Service Manual