Over Current Protection; Teletext Display - Daewoo DTK-28 Service Manual

Chassis : cp-850/f

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CP-850/F Service Manual

5.4.5 OVER CURRENT PROTECTION

In case of overload, the SMPS secondary voltages will drop. The voltage on pin 18 of microcontroller drops below a

reference voltage (x.xxV). The controlling software which continuously monitors this voltage will switch the set to stand

by mode. To power on the set again the user must switch it off using the main power switch. Appropriate hysteresis

guaranty a reliable operation.

National character option bits C12, C13, C14 are transmitted in the page header of a given teletext page. The national

option bits are intended to change (or exchange) 13 characters within the G0 character set, according to the needs of

each national language.

These codes represent, for a given broadcaster, the intended language that the teletext page should be displayed in. As

there are only 3 bits, there are only 8 codes available to cover all the possible language combinations. This means that

for a received code there are several possibilities meanings, according to the local code of practice.

This is not as bad as it first seems, as we use the user-selected OSD language to identify the intention of the

broadcaster. For example, a user wishing to see Russian teletext should select

Russian OSD language, otherwise he would not have correct teletext display on the TV.

The table below allows the reader to understand the relationship between selected OSD language (which is under user

control), the teletext language display (selected by national option bits in transmission page header) and the Packet 26

language selection (selected within packet 26 of the transmission page).

An example: For Greek teletext display, (if national option code 1 1 1 is received from the broadcaster), the user should

select the Greek OSD language. Even if English, French, German, Italian, Spanish, Dutch, Danish, Finnish, Norwegian

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