Shure Four Channel Automatic Microphone SCM410 - Manual (Page 14)

14
INTERNAL MODIFICATIONS
• Only make changes to jumpers (X) and resistors (R). The circuit
board contains holes where resistors are to be added.
• For Channel modifications, the first character of the reference desig-
nator indicates the channel number,(i.e., R1027 refers to a Channel
1 resistor, X2001 refers to a Channel 2 jumper, etc.). Modifications
affecting the Master section are preceded by a “9" (i.e., X9001).
• All Channel modifications in this section use Channel 1 as an
example.
NOTE: Remove AC power before opening the unit.
DISASSEMBLING THE SCM410/SCM410E
To access the printed circuit board for internal modifications, proceed
as follows:
1.
Remove the power cord from the ac power source.
2. Remove the knobs, retainer nuts, and washers from the front
panel, as shown in Figure 16
3. Remove the four screws at each corner of the rear panel.
4. Remove the two screws at each bottom corner of the front panel.
5. Slide the back panel and printed circuit board out from the rear of
the chassis.
CAUTION: When reassembling the SCM410, DO NOT
OVERTIGHTEN the knob retainer nuts.Damage to the internal
components will result if too much force is used.
INSERTING A 12 DB MIC PREAMPLIFIER PAD
A microphone preamplifier channel gain can be reduced by 12 dB. This
may be desirable with high-output microphones.
Procedure:
1. Short jumper X1000.
2. Remove resistor R1006.
DISABLING PHANTOM POWER BY CHANNEL
To disable phantom power for a given microphone input channel,
remove the resistor specified in the following table.
INSERTING AN INPUT LINE PAD
To insert a 40 dB line pad for a given microphone input, remove the
resistors specified in the following table.
DISABLING THE MASTER LEVEL CONTROL
The Master gain control can be disabled to prevent tampering. Refer
to the following table for gain levels and resistor values.
Procedure:
1. Remove resistor R9203.
2. Install new resistor at jumper R9173.
KNOB ASSEMBLY AND DISASSEMBLY
FIGURE 16
Channel Remove Resistor
1 R1005
2 R2005
3 R3005
4 R4005
Channel Remove Resistor
1 R1005, R1006
2 R2005, R2006
3 R3005, R3006
4 R4005, R4006
Master Section Gain Resistance
-6 dB 5.1 k Ω
0 10 k Ω
6 dB 20 k Ω