Abbreviation List - Philips 27PS60S321 Technical Service Data

SPMS
Protection Events
Several protection events are controlled bythe UOC:
BC protection , to protect thepicture tube from a too high beam current. The UOC has the
capabilityof measuring the normal back level current during the vertical flyback.So if for
some reason the CRT circuit is malfunctioning (i.e. highbeam current), the normal black
current will be out of the 75 μArange, and the UOC will trigger the power supply to shut
down. However,this is a high beam-current situation, the TV screen will be brightwhite
before the set is shut down.
E/Wprotection , two protection mechanisms are built in, over-currentand over-voltage.
In case ofover-current due to defective parts in the line deflection outputstage, a
high current will flow through resistors 3405//3406.If this current is large enough to
create a voltage drop of 0.7V across 3405//3406, transistor Q7606 (in A7 diagram)
will conduct and pin 80 of the UOC will be pulled down. Thereafter,the UOC will
shut down the power supply. In case of further currentincrease, the fused resistor
3411 is built-in for double protection.
In case of a high voltage appearing across capacitor 2401(dependent of the tube
size), which is high enough to trigger zenerdiode 6401 into conduction, transistor
Q7606 (in A7 diagram) willconduct and UOC is triggered to shut down the power
supply.
2
I C protection , to check whetherall I
In case one of these protections is activated, the setwill go into 'standby'.
The 'on' and 'standby' LEDsare controlled via the UOC.

Abbreviation list

Abbreviation
2CS
ACI
ADC
AFC
AFT
AGC
7/8/2004
2
C IC"sare functioning.
Description
2 Carrier (or Channel) Stereo
Automatic Channel Installation: algorithm that installsTV
sets directly from cable network by means of a predefined
TXTpage
Analogue to Digital Converter
Automatic Frequency Control: control signal used totune to
the correct frequency
Automatic Fine Tuning
Automatic Gain Control: algorithm that controls thevideo
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