Internal Modifications, Disable Master Level Control

INTERNAL MODIFICATIONS

WARNING: All modifications must be performed by qualified service tech- nicians.

This section describes SCM810 modifications that can be made using sol- der “jumpers” on the printed circuit board; the pads where jumpers may be used are placed close together so that a single solder drop functions as a jumper. Note too that:

1.he only printed circuit board legends used for these modifications are jumpers (X's) and resistors (R's).

2.Where resistors are to be added, through-holes are present on the board.

3.For individual channel modifications, the first number of the reference designation refers to its channel number, i.e., R1027 refers to a Chan- nel 1 resistor, X7216 refers to a Channel 7 jumper, etc. All references to Channels 1 through 8 in the following paragraphs use Channel 1 jumpers and resistors as reference. Modifications affecting the Master section are preceded by the number “9" (X901, etc.).

To gain access to the main printed circuit board, remove the 8 Phillips head screws securing the top cover, and remove the top cover. Most modifica- tions can be made from the top of the main board.

Line-Level Output to Mic-Level Output

Procedure: Short jumper X901. Remove resistors R900 and R909.

Disable Master Level Control

The Master gain control can be disabled so it cannot be tampered with. The table indicates the resistor value to be used for the desired gain.

Procedure: Remove resistor R9230. Install new resistor at jumper X914.

Master Section Gain	Resistance

-6 dB	5.1 kΩ

0	10 kΩ

6 dB	20 kΩ

Change Limiter Threshold

All three threshold settings (+16, +8 and +4 dBm) can be changed. To shift the threshold down by 6 dB, resistor R will be 82 kΩ. To shift the limiter thresholds up by 6 dB, R will be 330 kΩ.

Procedure: Remove resistors R9177 and R9180. Install new resistor R at jumper X907.

Local Aux Operation

With linked mixers, the Aux input from a modified mixer does not link. Procedure: Remove resistor R9024.

Direct Out to Post-Fader

A channel's Direct Out phone jacks can be changed from pre- to post-fader.

Procedure: Short jumper X106. Remove resistor R1011.

Direct Out to Post-Fader Send/Return (Insert)

Changes a channel's 1/4-inch Direct Out jack to a post-fader insert point. Send is tip of phone jack; return is ring. Insert jacks are useful for inserting line-level signal processors into a channel. For instance, a parametric EQ or compressor/limiter can be inserted into a channel for additional process- ing.

Procedure: Short jumpers X101, X102, X105 and X106. Remove resistors R1011 and R1020.

Direct Out to Gated Direct Out

This post-fader, post-EQ channel output is gated, but without NOMA. In this mode, if the Local/Global switch is in “Local”, a manual mix of channel in- puts is present at the Line output. The Off-Attenuation level of the Gated Direct Out signal is infinite.

Procedure: Short jumpers X104 and X906 (in Master section). Remove re- sistor R1011.