Internal Modifications - Shure SCM800 User Manual

HIGH-FREQUENCY SHELVING EFFECTS FIGURE 10

Internal Modifications

NOTE: Remove AC power before opening the unit.
ABOUT PRINTED CIRCUIT BOARD MODIFICATIONS
• A jumper is represented by "X" on the printed circuit board legend, a resistor is represented by an "R."
• The first number in the reference designator indicates the channel number; i.e., R1027 refers to a Channel 1 re­
sistor, and X7216 refers to a Channel 7 jumper, etc.
• Components in the Master section are preceded by the number "9" (X901, etc.).
• The circuit board contains holes where resistors are to be added.
• A single drop of solder can serve as a jumper between adjacent jumper pads.
• All Channel modifications in this section use Channel 1 as an example.
Inserting A 15 dB Microphone Preamplifier Pad
Each channel's microphone preamplifier gain can be reduced by 15 dB. This may be desirable with extremely
high-output microphones.
To pad the gain of the MIC position:
1. Remove surface mount resistor R1023.
2. Solder a 680 Ω resistor at jumper X112. For a greater gain reduction, use a resistor with a value greater than
680 Ω. Use a lesser value resistor for less reduction.
To pad the gain of the PHM (phantom) position:
1. Remove surface mount resistor R1026.
2. Solder a 1.5 kΩ resistor at jumper X110. This reduces gain by 8 dB. For a greater gain reduction, use a resistor
with a value greater than 1.5 kΩ. Use a lesser value resistor for less reduction
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