Service manual

The sawtooth voltage for the frame output stage is not generated by the HOP but by a
discrete circuit after the optocoupler 7610 via R3600 and R3601 a linear increasing
voltage over C2601 is built up with a large time constant.
The circuit around TS7603 is a current source, driving C2601 with a current value
derived from the E/W modulator. This will result in an S-shaped voltage on C2601 (also
known as EW-correction).
Flyback Generator
The frame output stage is supplied via the +13 V and -15 V coming from the LOT. The
output of the amplifier is 0VDC, so a coupling capacitor is not required.
During the (forward) scan, a supply of +13 and -15 V is sufficient to respond to the slow
changing current. The flyback generator puts a voltage of -15 V on pin 3. Because of
the voltage drop over zener diode D6622 (8.2 V), C2622 will be charged to 19 V: being
13 + (15 - 8.2 - 0.7) V.
During the flyback scan, the change in current per time is much larger, so a higher
voltage is required. The flyback generator will now generate a voltage of +13V on pin 3.
Added to the charge on C2622 this will give a flyback voltage of 32 V (depending on the
CRT size, this value can differ).
The IC amplifier (IC7620, pin 5) supplies the sawtooth current to the frame deflection
coil. The current through this coil is measured via R3620//R3621//R3622 and fed back
to the inverting input of the amplifier.
R3624 and C2624 on the output of the amplifier, form a filter for high frequencies and in
that way also prevents oscillations.
Peak voltages on the output, e.g. as a result of a possible flash, are damped by the
clamp circuit consisting of D6619, C2627, and R3627. The network consisting of R3625,
R3629 and C2629 form an extra damping circuit.