AUDIO TELEX ACM250P Operating and installation instructions

Australian Monitor
1 Clyde Street, Silverwater NSW 2128 Australia
[phone]
www.australianmonitor.com.au
SERVICE INFORMATION
AUDIO TELEX
ACM250P
POWER AMPLIFIER
CONTENTS:
OPERATION MANUAL
SCHEMATIC DIAGRAMS

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Audio Telex Communications Pty Ltd
ACN 00134S82 lncorporated in NSW
NSW & ACT
149 Beaconsfield Street
Private Bag 149
Silverwater NSW 2128
Australia
Ph 02 96/.71411
FaxO2 9648 3698
42 CommercialRoad
PO Box 871
Fortitude Valley QLD 4006
Ph 07 38521312
Fax [phone]
221277 Middleborough Road
Box HillVlC 3128
PO Box 151
Blackburn South VIC 3130
Ph 03 98907477
Fax [phone]
299 Fitzgerald Street
West Perth WA 6005
PO Box 404
North Perth WA 6906
Ph 08 9228 4222
Fax [phone]
Electronic Concepts Pty Ltd
76 George Street
Thebarton SA 5031
PO Box 7034 Hutt Street
Adelaide SA 5000
Ph 08 82349444
Fax [phone]
K W McCulloch Pty Ltd
54a Albert Road
MoonahTAS 7009
Ph 03 62286373
Fax [phone]
Unit B, 11 Piermark Drive
PO Box 512
Albany NZ 1331
Ph 09 4159426
Fax [phone]il

ACM250P Power Amplifier
Product Description
The ACM250P is a 250 watt power amplifier with outputs for 4 ohms, 70 and 100 volt line. It may be desk or rack mounted but
comes standard as self standing with rubber feet. The ACM250P features a flat screwdriver accessible gain control on the rear panel.
The factory setting for the front panel gain control is I volt RMS.
Front Panel
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POWef BUttOn: This switch controls the switching of AC power to the amplifier. Rocking this switch turns the AC power to the
amplifrer on and off. When in the on position, the red neon in the body of the switch will glow.
Protect LED: A feature of the ACM250P is high temperature protection. In most applications, the internal cooling fan will most
probably never switch on. When used with demanding speaker loads or in difficult operating environments, the fan may regularly
switch on to cool the amp down and then switch offagain. This switching on and switching offis quite normal. The "Protect" function
is there to protect the amplifier from a high temperature problems which would only occur if the fan stopped working or became
clogged up. In this very rare occurance, the amplifier will shut down and the protect LED will illuminate. The amplifier will
automatically restart once it's internal temperature has fallen within "safe" limits. If the protect LED illuminates, it is best to switch
the amplifier off, let it cool down and then try it again. If the protect LED illuminates again, please contact either Audio Telex or the
company who supplied or installed the equipment.
Rear Panel
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3 Pin IEC Mains Power lnlet The operating voltage is 240 VAC @ 50 Hz or I l0 VAC @ 60 Hz (special order). The AC
power voltage level is not extemally user adjustable but is factory pre-set. The inlet is equipped with an inbuilt AC fuse holder fitted
with a 6 amp fuse plus a spare found within the holder. Power consumption is 400VA. I Please ensure that the mains power
cord is disconnected before attempting to check or replace this fuse.
Direct Output Terminal Strip: These screw terminals allow access to the direct outputs of the amplifier. Reading from
left to right the terminals are-
. Low Impedance Common
. 4 Ohms
I Spare
r Constant Voltage Common
. 70 Volt Line
' 100 Volt Line
TWin DG fuse receptacles: Access the DC fuses is by tuming the cap half a tum counter-clockwise with a screwdriver.
The value of the fuses is 10 Amps slow blow. I Please ensure that the AC power switch is in the 'oI? position and that the
mains power cord is disconnected before attempting to check or replace this fuse.
Signal lnpUt SOCketS: Signal input to the ACM250P is via a 3 pin XLR socket and is rated at lOK Ohms and is active
balanced. The two sockets are provided for bridged in/out connection. Pin connections are Pin l:Earth. Pin 2=Active Positive (+).
Pin 3:Active Negative (-).
Gain COntfOl LeVel: A recessed (screwdriver adjustable) gain control is located on the back panel. Tuming the control
clockwise will increase the output of the ACM250P towards it's maximum output level while turning the control counter-clockwise
will decrease the output level. Adjust this control for the desired output level depending on the level of the input signal (from a mixer
or other signal source). The factory default setting for this control is such that a I volt input will give a 100 volt output.
Fuse Sizes
Mains 240 VAC: 6 Amperes Slow Blow
DC: Z x 10 Amperes Slow Blow
Notes
There are no user adjustable controls inside the amplifier so the cover should only be removed by qualified service personnel. In all
cases the mains power lead should be disconnected before the cover is removed.

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Title
Number RevisionSize
A3
Date: 16-Oct-2002 Sheet of
File: C:\Protel Files\CDTRAX\CD6241-1.DDB Drawn By:
IC1
LM741
R1
10K
R2
10K
R3
10K R4
10R
R5
10K
C1
100P
C2
4u7
C3
4u7
C4
4u7
R6
50K
R7
1K
C5
100P
C6
.1u
1
2
3
4
5
6
7
8
910
11
12
13
14
15
16
17
18
IC2
16C54 C7
22P
C8
22P
XT1 R8
1M
R9
560R
R10
1K
R11
1K
V1
BD139
V2
BC546
V3
BC546 R12 100R
C9
4u7
R13
4K7
D1
20V C10 100u
C11
100u
R14
4K7
R15
4K7
C12
4u7
C13
47u
R16
4K7
R17
10K
R18
1K
IC3
78L05
R19
10R
C14
47u C15 4u7
45VDC
INPUT
12
3
X1/1
GND
FAN
INPUT
1/2 VCC
GND
19V VCC
FAN PTC
HI TEMP PTC
NC
HI TEMP LED
6X 10K
ACM250-P INPUT
CD6241-1
11
RS

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Title
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Date: 16-Oct-2002 Sheet of
File: C:\Protel Files\CDTRAX\CD6240-11.DDBDrawn By:
R42
1K
R37
1K
R36
100K
C7
4u7
D1
R35
100R
R32
1K5
R28
.1R
R27
.1R
C10
.1u
C9
.1u
D7
R1
68K
R2
68K
R3
10K
R4
10K
R5
680R
R6
680R
R7
100R
R8
100R
R9
100R
R10
100R
R13
1K
R14
1K
R15
150R
R16
150R
R17
1K
R18
1K
R19
470R
R20
470R
R21
10R
R22
10R
R23
470R
T3A
T3B
V1
V2
V3
V4
V10
V15
V11
V16
V5
V6
P1
500R
D4
R39
150R
C5
820P
R50
.22 R51 .22
C1
2u2
C2
2u2
R55
.22 R56 .22
R38
150R
D5
P2
500R
C6
820P
IC2
78L05
T2
V7
BC640
D6
T1
S1
C1. C2.
D8
D9
F3
4A SB
F2
10A SB
N1
R31
1K
IC1A
LM833
IC1B
LM833 R11 1K
R12
1K
R24
10K
R25
10K
R26
10K
R40
10K
R41
47K
R43
10K
C3
.47
C4
100P
C11
100P
V8
BD139
R45
4K7
D15
12V
V9
BC546
C13
2u2
C14
47u
R46
4K7
R47
2K2
D16
4V7
R48
70DEG
R49
100DEG
BR1
F1
10A SB
IC3
7818 C8
4u7
C15
100u
R44
470R
D2
C12
.47u
1/2 VCC
CD6240-1
ACM250 POWER AMP
GND
INPUT
X3/1
X1/1
4 OHM
X2/9
X2/7
XT/5
X2/4
X2/2
X2/1
X2/3
X2/8
X2/6
240VAC
COM
COM
70VAC
100VAC
11
RS
FAN
TEMP FAN
TEMP CUTOUT
+45VDC
+45VDC
NC
FAN
V10-V19=TIP35C
R50-59=.22R
PLEASE NOTE:
BC639
BC639

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Title
Number RevisionSize
A3
Date: 14-Apr-2004 Sheet of
File: C:\PDF CCT\CD6240-12.DDB Drawn By:
C12
.47u
D2
R44
470R
C15
100u C8 4u7
IC3
7818
F1
10A SB
BR1
R49
100DEG
R48
70DEG
D16
4V7
R47
2K2 R46
4K7
C14
47u
C13
2u2
V9
BC546
D15
12V
R45
4K7
V8
BD139
C11
100P
C4
100P
C3
.47
R43
10K
R41
47K
R40
10K
R26
10K
R25
10K
R24
10K
R12
1K
R11
1K
IC1B
LM833
IC1A
LM833
R31
1K
N1 F2
10A SB
F3
6.3A-SB
D9
D8
C2.C1.
S1
T1
D6
V7
BC640
T2
IC2
78L05
C6
820P
P2
500R
D5
R38
150R
R56
.22
R55
.22
C2
2u2
C1
2u2 R51
.22
R50
.22
C5
820P
R39
150R
D4
P1
500R
V6
V5
V16
V11
V15
V10
V4
V3
V2
V1
T3B
T3A
R23
470R
R22
10R
R21
10R
R20
470R
R19
470R
R18
1K
R17
1K
R16
150R
R15
150R
R14
1K
R13
1K
R10
100R
R9
100R
R8
100R
R7
100R
R6
680R
R5
680R
R4
10K
R3
10K
R2
68K
R1
68K
D7
C9
.1u
C10
.1u
R27
.1R
R28
.1R
R32
1K2
R35
100R
D1
C7
4u7
R36
100K
R37
1K
R42
1K
A
BC639
BC639
PLEASE NOTE:
R50-59=.22R
V10-V19=TIP35C
FAN
NC
+45VDC
+45VDC
TEMP CUTOUT
TEMP FAN
FAN
SBG
11
100VAC
70VAC
COM
COM
240VAC
X2/6
X2/8
X2/3
X2/1
X2/2
X2/4
XT/5
X2/7
X2/9
4 OHM
X1/1
X3/1
INPUT
GND
ACM250 POWER AMP
CD6240-1
1/2 VCC