JVC 250 High Voltage Power Supply HVPS, Remove the front cover see .1 Projector Covers

Chapter 3---Electrical

2.Turn the AC Circuit Breaker to the OFF position and unplug the AC Power Cord.

3.Remove the front cover (see section 6.1 Projector Covers ).

4.Remove the lower-right-side panel by removing the five Pozi-drive screws securing it.

5.Remove the five Pozi-drive screws securing the EMI Shield. Slide the shield to the left and remove it.

6.Disconnect the INPUT AC plug.

7.Disconnect the two CONTROL SIGNALS cables. The /LAMP_OK signal jumper is attached to the CONTROL SIGNAL cable by a cable tie. Do not cut this cable tie.

8.Disconnect the Arc Lamp Power Supply OUTPUT cables from the (+) and (-) terminals. Take care not to damage the 470µf capacitor across the output cables. The (+) cable has a red shrink tubing on it; the (-) has a black shrink tubing on it.

NOTE: The capacitor on the output of the Arc Lamp Power Supply filters transient spikes from the Arc Lamp when it arcs. Re-attach the capacitor with the Arc Lamp output leads during reinstallation of new Arc Lamp Power Supply.

9.Remove the 1 Pozi-drive Phillips-head screws from the bottom of the front of the Arc Lamp Power Supply. The other screw was removed with the EMI Shield.

10.Carefully slide the Arc Lamp Power Supply out of the projector.

11.Replace the Arc Lamp Power Supply in the reverse order.

High Voltage Power Supply (HVPS)

HVPS - Main Functions

The High Voltage Power Supply provides the following functions:

!Phase locked loop circuit for synchronization of the High Voltage Power Supply to the HVPS_SYNC

!Generation of Anode voltages (25 kV) for all three CRTs (RGB)

!Generation of Focus voltage (G3) (7 kV) for all three CRTs (RGB)

!Generation of G2 (1200 V) supply voltage for the Video Amplifier PCB.

!Generation of G1 (-150 V) supply voltage for the Video Amplifier PCB.

!Dynamic Focus Amplifier using horizontal and vertical parabolas supplied to the High Voltage Power Supply.

!External CRT Protection and generation of /HV_OK signal

Model 250 Service Manual 3-9