17
10.2MalfunctionAnalysisonAmplifiedPart
Sequence
No.
CircuitFunction Failure
1
ClassABPower
Output
‐ Power supply protection: Breakdown of any one power transistor
willcauseashortcircuitandresultstohighcurrentprotection.
‐ Amplifierprotection:+15V/‐15Vifthepowersupplyisabnormalwill
leadtotheDCoutput,amplifierwillgointoprotectionstatus;
‐
Nocliplimit;
‐ Amplifierself‐excitated;
‐ Cross‐overdistortion;
‐ IC/5532 damaged, unbalanced of the of positive and negative bias
voltage,hasDCoutputandpoweramplifiergoesintoprotection.
2
Overload/
Short‐circuit
Protection
‐ Outputshort‐circuitandnoprotection,
‐ Start–upprotection;
3 ClipLimitCircuit
‐ Nocliplimit;
‐ Cliplimitdelayed;waveformjitterwhenincliplimit;
‐ Volumewillnotgomaximumgraduallyafterstart‐up.
4
VHF/Over‐heat
Protectionand
DelayCircuit
‐ The protection delay circuit is a collection of VHF, short circuit,
over‐heat,DC‐protection,aswellasstart‐updelay.
When the Protection function and start‐up delay is abnormal please
checkthiscircuit.
5 DCProtection
‐ Nooutput‐relaydoesnotpull‐in,firstcheckwhetheritisnormalfor
24Vpowersupply,Q6baseisahighlevel.
‐ On/offhasthesoundofshock‐alongpull‐inontherelay;
RepairingGuide:
1)Whenrepairingtheamplifier,pleaseseriesconnecta100W—200Wlamptostarttheequipmentto
avoidthedamageofrelateddevice.
2)The circuitof CH1 andCH2 is the samebutthe sequence No. of device isdifferent, all thetesting
parametercanbeshared;
3)Power
amplifierprotectionmeansthepowerandprotectionindicatorsonthefrontpanelarelit;
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