Specifications

I
WARNING
I
No user-serviceable parts inside. Refer all ser-
vicing, including modifications, to qualified ser-
vice personnel.
AMS mixers can be disassembled for modification as
follows:
1. Remove line cord from ac power source.
2. Remove screws securing top cover to chassis.
3. Remove individual Channel boards by removing: [a]
Channel board bottom screw; [b] Channel Level con-
trol knob and nut; [c] Channel-On LED leads; and
[dl
ribbon cable connector.
4.
When replacing Channel boards, be sure to perform
steps
3[a] through 3[d] in reverse order.
240-Volt Operation
To change the AMS mixer operating voltage from 120 Vac
to 240 Vac, follow these steps.
1.
Locate the Power board [A5].
2. Remove the transformer TI plug from connector P501
[marked 120 VAC], and carefully insert it in connector
P502, making sure all four pins are properly engaged.
3.
Remove the 0.25N250V fuse from the fuseholder
marked F502 and insert the
TI 25 mN250V fuse
[packaged with the AMS mixer] in the fuseholder mark-
ed
F501.
4. Replace the ac connector with one designed for the
240-volt source. If the mixer is to be used outside the
U.S. and Canada, local regulations may require replac-
ing the line cord with one having wire insulation colors as
follows:
"Live" or Earth or
"Hot" Neutral Ground
U.S., Canada
Black White
Green
Europe
Brown Blue
Green/Yellow
5.
Mark the rear panel of the mixer with the new operating
voltage.
Hold Time Increase
The 1 .O Sec position of the rear-panel Hold Time switch can
be increased to 2 seconds as follows.
1. With the top cover removed, locate the Master board
[A21.
2. For AMS4000 mixers, no further disassembly is
necessary; for
AMS8000 mixers, remove the Channel
8 board as described above.
3. Solder a
30k, lh W resistor in the Master board holes
marked
XR201 [see Figure 251.
4. Reassemble the mixer and mark the Hold Time switch
position
"2.0" instead of "1 .Om.
Pre-Fader to Post-Fader
The Channel Level control can be rewired to also control the
rear-panel Direct Output level as follows.
1
. Remove the top cover and the Channel board to
be modified.
2.
Locate jumper XI01 at the top center of the
Channel board, and jumper holes
XI02 at the
bottom center of the board [see Figure
261.
3.
Unsolder the jumper at XI 01 and solder it or a
new jumper in the holes of
XI 02.
4.
Reassemble the Channel board and top cover as
described above.
MASTER BOARD A2: XR201
FIGURE 25
Mute Precedence to Override Precedence
As supplied, if a channel's Mute In and Override In logic ter-
minals are both grounded, the mute function will take
precedence over the override function and the channel will
be muted. With the following modification [both logic ter-
minals grounded], the override function will take precedence
over the mute function and the channel will be forced on.
Note that after modification the Channel Level control will
still turn the channel off at the full counterclockwise position
[independent of the Override IN terminal].
1
. Remove the top cover and Channel board to be modified
as described above.
2. Locate jumper
XI04 and jumper holes XI03 on the
CHANNEL BOARD A1: XI01 AND XI02
FIGURE 26