Download Shure M367 User guide

INTERNAL ADJUSTMENTS
WARNING
All internal modifications must be performed by
qualified service technicians.
WARNING
All internal adjustments must be performed by
qualified service technicians.
Disassembling the M367
1. Remove the mixer top cover as described above.
NOTE: All internal adjustments require only removal of the top
cover.
1. Remove battery compartment.
2. Carefully remove three multi–pin cable assembly connectors
from upper front PC board (nearest front panel).Remove three
Phillips head screws which secure PC board. Remove upper
front PC board.
2. Remove four screws securing two plastic end caps and one
ground–bonding screw on the side opposite the battery
compartment.
3. Carefully remove four multi–pin cable assembly connectors
from upper rear PC board (nearest rear panel).Remove three
Phillips head screws which secure PC board. Remove upper
rear PC board.
3. Slowly slide cover up and off chassis.
VCA Distortion Factory Preset Potentiometer R607 (see
Figure 5)
DO NOT ADJUST! This potentiometer is precisely calibrated
on each mixer for minimum distortion.
4. Perform modification (refer to appropriate procedure below).
Note that all modifications can be performed without removing
the main PC board.
VU Meter Adjustment (see Figure 5)
This trimpot adjusts the VU meter to indicate 0 VU at a preset
output level. The factory setting is +4 dBm. The user adjustment
range is –10 dBV to +4 dBm (–6 dBV to +8 dBm with DIP switch
1 down.
5. Reassemble M367 by performing above steps in reverse, assembling the Phillips screws in the order indicated on the upper front and upper rear PC boards.
Changing Operating Voltage Range
The M367 and M367E can be internally modified for an alternate operating range.
M367 Operation at 220–240 Vac
1. Disconnect the ac power and remove the mixer top cover as
described above.
VU METER
CALIBRATION
TRIMPOT
R684
2. Locate Voltage Selector switch S301 adjacent to power transformer T301. Use a screwdriver to move the center dial so
“230” is opposite the indicator. Replace the top cover.
VCA
DISTORTION
TRIMPOT
R607
3. Open the rear–panel fuse compartment and replace the 0.125
mA, 250 V fuses (operating and spare) with 0.063 mA, 250 V
fuses of the same size and type. Close the fuse compartment.
M367E Operation at 100–120 Vac
(ACCESSED
THROUGH
HOLE IN
UPPER FRONT
PC BOARD)
1. Disconnect the ac power and remove the mixer top cover as
described above.
2. Locate Voltage Selector switch S301 adjacent to power transformer T301. Use a screwdriver to move the center dial so
“115” is opposite the indicator. Replace the top cover.
DIP SWITCH
S701
3. Open the rear–panel fuse compartment and replace the 0.063
mA, 250 V fuses (operating and spare) with 0.125 mA, 250 V
fuses of the same size and type. Close the fuse compartment.
INTERNAL ADJUSTMENTS
FIGURE 5
To set the VU meter to a value other than the factory setting (0
VU = +4 dBm), proceed as follows:
Changing Line Level Output Impedance to 600Ω
1. Locate resistor R621 (near IC U602 pin 8) on main PC board
and remove it.
1. Connect a 600 Ω load to an XLR output set for Line.
2. Locate empty pads X621 (near resistor R621).
2. Connect an ac voltmeter with 1 MΩ or greater input impedance
(Fluke 77 or equivalent) in parallel with the load.
3. Solder a 430 Ω, 1/2W resistor through the holes at X621.
3. Pull out the channel 1 Gain knob to activate the 1 kHz tone oscillator.
Changing Unswitched Line Output to Mic Level
1. Locate resistor R632 (near output transformer T601) and remove.
4. Adjust the 1 kHz tone oscillator level with the Master gain control until the ac voltmeter reading is at the level desired.
2. Locate empty pads X632 (near transformer T601).
3. Solder a jumper wire through the holes of X632.
5. With the M367 top cover removed, adjust the VU Level Calibration trim pot R684 with a screwdriver until the VU Meter
reads 0.
Changing Mixer Audio Levels in Headphones (Pull/Monitor Switch Activated, DIP Switch S701 Position 4 Closed)
1. Locate empty pads X649 (near Phones potentiometer R648).
6. For 0 VU settings between +4 and +8 dBm, set internal DIP
switch S701 position 1 “down”, and perform steps 1 through 5.
2. Solder a 68 kΩ, 1/4 W resistor through the holes at X649 to hear
program audio 12 dB down from standard headphones level
with Pull/Monitor switch on (pulled out).
INTERNAL MODIFIABLE FUNCTIONS
Selected internal functions of the M367 can be modified by the
user to fit special applications. All modifications are performed
through solder points accessible on the main PC board. Procedures for performing these modifications are listed below.
3. Solder a 24 kΩ, 1/4 W resistor through the holes at X649 to hear
program audio 6 dB from standard headphones level with Pull/
Monitor switch on (pulled out).
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