JVC 330, 370 SC, 340 SC service manual Circuit Boards, Backplane Board 100571

Chapter 2—Functional Descriptions

The card cage is hinged in the rear to allow it to be folded backward for access to the CRT housing (when folding the card cage backward be sure that nothing is plugged into the rear electronic jacks or the plugs could be severely damaged). During normal operation, the card cage should be in its upright position to ensure proper cooling of the CRT enclosure.

A holddown screw is provided to secure the card cage and prevent it from rotating backward during shipping or when the projector is mounted in an upward- pointing position. The holddown screw is located on the lower, front, right corner of the card cage.

The rear panel of the card cage provides mounting for the projector controls. The VPB, which receives all image and sync inputs, is secured to the rear panel by four screws. The RS-232 control connectors and the IR receiver and repeater inputs as well as the LED dot matrix status display are located on the lower left of the rear panel. The projector model and serial numbers are also found on the rear panel.

2.6 Circuit Boards

The Model 330, 340SC and 370SC projectors have a total of twelve (12) accessible circuit boards. Seven (7) boards are located within the card cage (Figure 2-9) and five (5) are located outside the card cage (Table 2-2).

Table 2-2Circuit Boards Outside Card Cage

No.	Description	330	340SC	370SC
1	Ignitor	102083	102207	104475
3	Video Amp Boards (VABS)	103567	103567	103567
1	Backplane	100571	100571	100571

Each circuit board can be replaced individually except the Backplane board and the PLL. The PLL is replaced with the RTG as a unit. The Ignitor was previously described in Section 2.4.2. The circuit boards covered in this Section are listed in Table 2-3.

Table 2-3Circuit Boards

Page	Circuit Board		P/N
2-18	Raster Timing Generator	(RTG)	100568	and PLL
2-26	Horizontal Deflection Board	(HDB)	102523
2-34	Vertical Deflection Board	(VDB)	102521
2-44	Video Processor Board	(VPB)	104672
	and optional Decoder Board
2-55	Video Amplifier Board	(VAB)	103567
2-58	System Controller Board	(SCB)	104668
2-70	Backplane Board		100571

Model 330, 340SC and 370SC Service Model 2-15