Mitsubishi Electronics WS-65513 Time Shift Recording Power Supplies, Standard Standby Supplies

Standard Standby Supplies

Two Standby supplies are generated directly from T9A20, 12VS and 6VS. Both of these supplies are directed to the DM module, and are denoted as 12V- DM and 6V-DM.

A 30VS supply is derived from the 12VS source using voltage doubler circuitry, comprised of D9A31, D9A32, C9A32 and C9A27. The resulting 30VS is the source for a 28V-DM supply.

Standby Power Distribution

Figure 3-6illustrates the Standby Power Distribution. As mentioned earlier, the 12VS is source for 12V- DM,and through the Voltage Doubler circuitry is the source for 30VS and 28-DM supplies. The 12VS is also directed to Horizontal Drive Circuitry and is the Start-up voltage source for the Switched Supply Regu- lator.

In addition to being the 6V-DM source, the 6VS sup- ply supplies power for CRT Protect circuitry, and is the source for the 3.3V-1 and 5V-2 supplies.

Time Shift Recording Power

Supplies.

The Time Shift Record Supplies are switched supplies derived from the Standby 12VS supply. They are acti- vated during Time Shift Recording and when the PTV is switched On. The Time Shift Power Supply circuit is shown if Figure 3-7.

The supply is activated by the PON-1 command from the Control Circuitry. When Off, the PON-1 line is low, holding Q921 On, which holds Q9A20 Off by pull- ing its Gate low.

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