PROEL HPX Series - HPX900;1200;2400;2800 Input Board; Input Board Malfunction Analysis

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13HPX900/1200/2400/2800InputBoard
13.1CircuitDiagramofInput
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13.2MalfunctionAnalysisonInputBoard
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Sequence
No.
CircuitFunction Failure
1
Stereo/Parallel
/BridgeSwitch
Circuit
‐ Poorconnection in SW1will cause theparallel and bridge indicator
doesnotshine;
‐ PoorconnectioninSW1willcausednooutputinonechannelwhen
amplifierinstereo,parallelorbridgemode;
2
BassBoost
Circuit
‐ PoorconnectionofSW2willcausenobassincreaseinCH1orCH2
‐ Whenincreasethebasswillcausethesounddistortion;
3
Sensitivity
SwitchCircuit
‐ Poor connection of SW3 will cause the unbalanced output of left
andrightchannels;
4 ClipLimitCircuit
‐ No limit in CH1 or CH2 caused by the damage of L1, L2 linear
photoelectricalcoupler;
‐ There is still larger signal output after start protection
function‐becauseVR1/VR2isnotinthebestvalue;
5
±15V
powersupply
‐ Power supply imbalance in +15 V or‐15V will cause a serious
distortion when volumeincreased,poweramplifieriseasy to go into
protectionfunction;