JVC 330, 370 SC, 340 SC service manual External Power Requirements, Electronics Systems Overview

Chapter 2—Functional Descriptions

WARNING!!! The HJT Model 330, 340SC and 370SC projectors use high voltages and high currents. Operation with covers removed exposes personnel to these dangerous conditions and may result in serious injury or death. No user-serviceable parts are contained within the projector. Refer all maintenance to only factory authorized and trained technicians.

The projector cover is a two-piece molded assembly. It is fastened to the projector frame by six (6) screws: two (2) on the rear cover; and four (4) on the front cover.

The fan intake side of the cover (right side) has filters on the intake vents. Periodic cleaning of the filters is required and should be performed in accordance with the procedure in this manual (Section 4.3). To avoid overheating the projector, ensure that the cover vent ports are free of obstructions at all times and that an adequate supply of fresh air is provided to the projector during operation.

2.2 External Power Requirements

The projectors require 208V to 240V, 50 Hz to 60 Hz, single-phase AC power. The units are equipped with an attached AC power cord and 3-prong twist lock plug (Model 330 and 340SC use Hubble Model 2323; Model 370SC uses Hubble Model 2623 or equivalent).

CAUTION! Operation at voltages and frequencies outside of these listed parameters may cause damage to the projector and will void the warranty.

2.3 Electronics Systems Overview

The objective of this portion is to provide a good general understanding of the projector electronics. The understanding gained will enable service personnel to more effectively maintain the projector to produce the desired result—a great picture on the screen —and quality you can see.

The Electronics Systems portion of this manual is based on block diagrams. The diagrams used have been drawn with two purposes in mind. First, they are general enough to be able to gain an understanding of the overall function of the various components of the system. Second, the block diagrams contain enough detail to make them valuable as a troubleshooting tool should the need arise. Schematics are not used but, where necessary, simplified circuitry is shown to aid in understanding the capabilities and/or limitations of the system. Discussion of troubleshooting is included but is largely confined to symptoms and identification of failed assemblies.

The Hughes-JVC Model 330, 340SC and 370SC projectors are multi-sync projectors capable of data, graphics, and display from 15KHz to 90KHz

Model 330, 340SC and 370SC Service Manual 2–3