Beam Current Limitation - Loewe Q2500B Serviceanleitung

Technology of Q 2500 colour TV set
D531
12(9)
R531
5
10
T531
The second protective switch monitors the V
flyback pulse that is fed from I 561 /pin 6 via
R 563 to the pin connector W 511 /pin 4. On
the signal board this V flyback pulse is recti-
fied by diode D 2591/1769 and integrated with
capacitor C 2592/2593. With the voltage avail-
able on capacitor C 2992/2593, Q 2594 con-
ducts. The collector of Q 2594 is then at the
same potential as L, and diode D 2594 is
blocked.
If there is no flyback pulse due the absence of
a V output stage, no voltage can build up on
capacitors C 2592/2594 and Q 2594 blocks.
Pin 94 of the CCU is set to H level via diode D
2594.
Document Q 2500

Beam current limitation

C511
32kV
Uvid
R552 R551
Focus
D549
D548
UG2
C549
W511/Pin11
FP
Basic board
Signal board
U8
R2604
R2611
D2611
R2609
C2608
R2608
R1043
R2608
D2544
FP
R2636
Q2638
R2637
If pin 94 of C 161 is set to H level by the ab-
sence of a V flyback pulse in the operating
condition of the unit, as described, after 2
seconds the CCU switches the device back to
standby operation. This permits safe shut
down of the device with a faulty deflection
controller.
2.7 Beam current limitation
To limit the beam current the Q 2500 chassis
is provided with an average value control. The
limit switch is integrated into TDA 9332.
32
R2603
I 2521
BCL
43
Video/deflection
Processor
4
14
R2606
R2544
R2547
D2549
R2549
U8
R2546
Q2639
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