Weak current College】 【public broadcasting system debugging and open testing.

<br> Broadcasting system debugging mainly refers to the broadcasting system installation has been completed, the device installation process is complete, the routine check and made opening test and quality evaluation, its main work content: transmission line check, with checks, insulation resistance measurement ., grounding resistance measurement, test and debug, power supply, antenna, system test, the opening of the sound pressure measurement and quality evaluation: <br> 1. transmission line check <br> <br> Broadcasting transmission lines are divided into various indoor .and outdoor wiring, checks should be checked line terminals from the device disconnected, follow construction plans, broadcasting system map to check the transmission wiring is correct, the existence of a short circuit, circuit breaker, mixed line failure; Terminal numbers are complete, correct ., and whether there is a terminal block welding. Fault for being discovered each exclude tricks and Terminal retightened connection; various plugs, socket connection is used for welding, wiring is correct, reliable, complete shield connection is good, and meet the requirements. < .br> <br> Second, the matching check <br> <br> Follow the construction drawing examination each loop or how the device line transformer with correctly, especially the multi-tap transformer connectors are often easily mistake then, pay attention to check missed ., received, transformer primary secondary reversed; the figure check transformer, capacity and impedance matching, <br> <br> III. determination of insulation resistance <br> <br> Will be broadcast at the ends of the connector line, used to measure .its 500V megohmmeter, wire insulation resistance. Measuring project: wire and cable and wire and insulation resistance of the insulation resistance is generally not less than 0.5 M Ω, the for each loop resistance shall be carried out by numerical measurement, the measuring loop should complete .records, as the debug report to construction unit. <br> <br> Fourth, grounding resistance measurement <br> <br> Broadcasting system grounding resistance, mainly in the broadcast room on the ground; measuring with grounding resistance tester. <br> .<br> Broadcast room amplifiers, power surge arresters, grounding resistance is usually not greater than 10 Ω, when the broadcasting system's capacity is over, such as single 150W set of ground very difficult indeed mission, and electric equipment combined with a set of ground ., but the ground require grounding resistance should not be greater than 4 Ω, and should set up a dedicated grounding line. <br> <br> 5. power test <br> <br> On the measurement of AC power supply voltage, power .supply wiring should not appear short circuit, open circuit, in the power switch on / off operation test, check the power display signal; standby power supply interchangeable equipment check test, battery voltage measurement of output; on rectifying charging device check measurements; do simulation .power test, verify that the power supply does changeover devices work reliably. <br> <br> 6. system opened test <br> <br> In the above check problems discovered in all changes have been completed, the check test shall meet the .requirements, you can do a system test, systems opened opened test should separate equipment, individual service. <br> <br> 1. open the amplifier <br> <br> First disconnect all output lines, pull the plug on the whole of .the input signal, the amplifier's "volume" spin button to spin and power it on, open the amplifier switches, observation of the displayed signal is normal, no machine noise. <br> <br> 2. open the front-stage amplifier < .br> <br> When the amplifier opened everything works, you can open the front-stage amplifier. Connecting the front-stage amplifier power, the observation of various display and plug in the front-stage amplifier and power amplifier of the join line. .<br> <br> 3. microphone test <br> <br> When the amplifier and the front-stage amplifier works fine, the front-stage amplifier and amplifier "volume" knob to the minimum, insert the microphone plug to the microphone .with voice signal, adjust the volume knob "," listening on headphones to hear the sound output. At this point the amplifier or the front-stage amplifier "function" knob rotation to the microphone. When all the way to the microphone jack test finished ., in the same way on each microphone input channels to experiment. <br> <br> 4, the recorder input <br> <br> The front-stage amplifier or amplifier "function", rotary knob to enter the stall, and the .recorder is switched on the recorder input circuit to play the recording tape, adjust the volume size, the observation of the input signal, distortion and noise. <br> <br> 5, receiving tuner opening test <br> <br> Connecting the .tuner power, receiving broadcasts test receive, according to FM radio reception, repeatedly adjust the FM receiver antenna for optimal reception. And watch the interference and distortion. <br> <br> 6. output circuit test <br> <br> The front .-stage amplifier or amplifier input recording or record signals, the "volume" to a minimum, opened the way how the device, the "volume" to the middle position, the observation by the speaker volume, clarity and noise; and then the " .volume "rotary to most, there is no distortion observed; and adjust the speaker volume controller, listening to the sound distortion and volume changes. For serious distortion of the speakers should be line transformers, speakers, coil, identify problems and should be repaired or .replaced. <br> <br> Using the above methods on each loudspeaker equipment circuit to test, if each speaker on the circuit are pronounced correctly (ie, low noise, clear, low distortion), you can open all speakers, sound columns, .adjust the volume size, repeated tests multiple times, exclude a variety of installation problems. <br> <br> <br> <br> <br> <br>.