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SI-125 Power Amplifier Manual 

 

Optional Modules 

Additional functionality can be added to the SI-125 Power Amplifier with the factory installation 
of one of the following optional modules. 

Note: 

These modules must be ordered at the same time as the SI-125 Amplifier as they cannot be 
installed in the field at a later time. These modules are installed on the rear of the amplifier by the 
Telecor factory and therefore cannot be ordered independently without an amplifier. 

The PA-AM Power Amplifier Attenuator Modules provides the amplifier with the ability to 
support a 25 V input signal which is attenuated by -25, -45, or -70 dB. Refer to the 

PA-AM 

Power Amplifier Attenuator Module Manual

 for more information. 

The PA-MM Power Amplifier Monitor Module will monitor the operational status of the 
amplifier. As long as the amplifier is operating normally, a relay will be activated. Refer to the 

PA-MM Power Amplifier Monitor Module Manual

 for more information. 

The PA-PM Power Amplifier Paging Module adds three additional input options to the 
amplifier: one low impedance microphone and two balanced line level inputs. The three inputs 
have adjustable level and remote mute controls. The three inputs can also be assigned to one of 
three available priority levels. Refer to the 

PA-PM Power Amplifier Paging Module Installation 

Guide

 for more information. 

Troubleshooting 

Problem Description 

VU Meter registers a signal when 
no signal should be present. 

The 

amplifier may be oscillating

, possibly at a very high frequency. 

This may be caused by: running input and output wires close 
together, grounding the input, or incorrect grounding of the shield. 

The Current Overload light 
illuminates or flashes. 

This indicates that 

the amplifier is being overloaded

. Check the 

total speaker load on the amplifier. Also check for shorts in the output 
wiring and for shorts to ground. If the amplifier is being overloaded, 
reducing the load or the gain should solve the problem. 

The Clip light illuminates or 
flashes. 

The input level to the amplifier is too great. 

Correct either by 

turning down the GAIN Control or by reducing the Input Level at the 
source of the amplifier’s audio signal. 

The High Temperature light 
illuminates. 

This indicates an 

excessively high temperature on the heat sinks

When this occurs, the output level is reduced until the temperature 
returns to normal. Overheating of the heat sinks is usually caused by 
insufficient ventilation or operating the amplifier in an overload state 
for an extended period of time. Check the loading and ventilation of 
the amplifier. 

Fuse blows. 

This indicates 

excessive current draw by the amplifier

. To replace 

the fuse, turn the amplifier Power Switch OFF and unplug the 
amplifier from the AC receptacle. Unscrew the fuse knob and replace 
the fuse with the same type, voltage and current rating as indicated 
on the amplifier and below: 
 
SI-125 amplifier uses a 

3AG 250V 3.5A 

fuse. 

If the new fuse also blows, unplug the amplifier and contact Telecor 
Technical Support. 

 

Summary of Contents for SI-125

Page 1: ... from overloading The amplifier also has circuitry to protect it from overheating The SI 125 Power Amplifier can have optional modules installed for additional functionality The PA AM Power Amplifier Attenuator Module allows the amplifier to support a 25 V input signal The PA MM Power Amplifier Monitor Module activates a relay under normal amplifier operation The PA PM Power Amplifier Paging Modul...

Page 2: ...ee the Troubleshooting section C CURRENT OVERLOAD Light If the current output of the amplifier exceeds its maximum power output the Current Overload light will illuminate and the output level will begin to be reduced The amplifier will continue to operate with the current limiting circuit reducing the output power If the Current Overload light illuminates see the Troubleshooting section D GAIN Con...

Page 3: ...overs the slot Please note that the accessory modules are not user installable They must be factory installed and ordered with the amplifier Do not remove any modules or the cover plate J INPUT LEVEL Switch The Input Level switch selects the range of the input level This switch works in conjunction with the GAIN Control on the front of the amplifier The Input Level switch should be set to match th...

Page 4: ...urn on either when there is excessive signal level on the input or when there is hard clipping present on the output The CLIP light will not turn on when the output level is clipped due to current overload Installation Before installing an SI 125 Power Amplifier carefully inspect the device for any damage that may have occurred during shipping The shipping package should contain only the Power Amp...

Page 5: ...own in Figure 5 Figure 5 Input Connections To reduce the incidence of ground loop hum oscillation or interference from other audio sources 1 Use a shielded cable for input wiring The shield must be grounded at one end of the cable only not both 2 Regardless of what type of input signal is supplied to the amplifier balanced or single ended the GND terminal should not be connected to the common term...

Page 6: ...pplications there is often a privacy switch in the room When this switch is activated it grounds one side of the room speaker line through a transformer Make sure that all these privacy switches are not in the Privacy position when measuring line impedance to ground These switches do not adversely affect the operation of the amplifier When measuring load impedance on a Telecor installation disconn...

Page 7: ...registers a signal when no signal should be present The amplifier may be oscillating possibly at a very high frequency This may be caused by running input and output wires close together grounding the input or incorrect grounding of the shield The Current Overload light illuminates or flashes This indicates that the amplifier is being overloaded Check the total speaker load on the amplifier Also c...

Page 8: ...ls on input and output Mas Con connectors are used with optional modules Controls Power Switch Illuminated GAIN Control Low Cut Switch Input Level Switch 1 V 100 mV Indicators Clip High Temperature VU Meter and Current Overload Protection Foldback current limiting Over temperature protection Primary circuit fused at 3 5 A Temperature Range 10 C to 35 C 14 F to 95 F Power Consumption AC 120 V 60 Hz...

Page 9: ...ansportation labor charges indemnity etc are not covered by this warranty and no responsibility for same will be assumed by us Our liability does not extend to consequential damage AUTHORIZED REPAIR STATION All participating Distributors and Dealers are authorized to accept Telecor products for return to us for repair or replacement or customers may return goods to us directly providing that retur...

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