Note After changing the output voltage, use a waterproof marker pen to note the correct, newly set value on the label-field OUTPUT VOLTAGE (20) on the rear of the appliance. Additionally note the corresponding output configuration (see diagram 5) on the label OUT CONFIG TYPE (20).
According to the description in diagram 7, adjust the switches S801 and S802 on the printed board assembly 89019.2 that are located next to the transformers on the bottom of the appliance’s enclosure (refer also to paragraph 5.4 ).
diagram 8 Printed board assembly 89019.2 showing the position of the switches S801 and S802
9.Additional Functions And Features (refer to qualified service personnel only!) 9.1 NRS 90206 Pilot Ton Surveillance
Using the extension-kit NRS 90206 provides continuous monitoring (surveillance) of the individual amplifier channels. This is achieved by sending an ultra low-level 19 kHz pilot tone through the device. It enters the signal path post level controls, runs through the amplification stages and gets filtered out and evaluated at the output. In case the result of this evaluation shows that the pilot dropped beneath a defined threshold or is missing at all, the corresponding READY indicator AMP 1 - 4 (7) goes out but the power amplifier upholds its normal operation. A fault-message is transmitted to the PROMATRIX Manager DPM 4000 (see PROMATRIX handbook). The extension-kit NRS 90206 comes as a plug-in board assembly and consists of a 19 kHz tone-generator and four selective 19 kHz receivers with evaluation stage.
Caution 
Unplug the mains cord and disconnect batteries before opening the appliance!
9.1.1 To Install The NRS 90206 Proceed As Follows (see diagram 9):
-for opening the appliance, please remove the 9 screws on the top of the appliance that lock the cover plate.
-the NRS 90206 gets retrofitted on the printed board assembly 89019.1, which is located behind the input printed board assembly 81331, in the front area, attached to the left side panel of the amplifier (in front view).
-Be sure to first insert the included board-guides before installing the printed board assembly, assuring the correct position of their guide grooves. The release lever of the guides marked “A” points to the top, while the one of the guides marked “B” points downwards.
-the NRS 90206 extension-kit needs to be inserted with its printed side pointing to the top, until it firmly locks in place. Make sure that the power resistors R917 to R920 that are located underneath the NRS-printed board assembly do not touch this board.
-closing the appliance: use the 9 screws M3 x 6 DIN 7500 to reattach the cover plate.
