Service manual

Audio Amplification
The audio amplifier part is very straightforward. It uses two integrated power amplifiers
(TDA2616). It delivers an output of 2 x 10WRMS to two full range speakers and/or
subwoofer.
The supply voltage is +28 V, generated by the main supply via L5506.
Muting is done via the 'SOUND-ENABLE' line connected to pin 2 of the amplifier IC and
coming from the Painter. This signal is inverted by TS7730, as a result of which at a
high level of the 'SOUND-ENABLE' signal, current is sinked from pin 2, and the IC
mutes.
CRT and SCAVEM (diagram F)
RGB Amplifiers
On the CRT panel, the RGB amplifier (TDA6108, IC7307) is located. Via the outputs 9,
8 and 7 the cathodes of the picture tube are driven.
The supply voltage for the amplifier is 180 V and is derived from the LOT.
SCAVEM
The SCAVEM-circuitry is implemented in the layout of the picture tube panel. It is thus
not an extra module. SCAVEM means SCAn VElocity Modulation. This means that the
picture content influences the horizontal deflection. In an ideal square wave, the sides
are limited in slope by a limited bandwidth (5 MHz).
SCAVEM will improve the slope as follows: At a positive slope, an SCAVEM-current is
generated which supports the deflection current. The first half of the slope the spot is
accelerated and the picture is darker, while at the second half of the slope, the spot is
delayed and the slope becomes steeper.