Pioneer xrp 440 service manual
This is the 8 pages manual for pioneer xrp 440 service manual.
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Extracted text from pioneer xrp 440 service manual (Ocr-read)
Page 1
"BLOCK DIAGRAM OF THE PROTECTION CIRCUIT"1. OUTPUT DC DETECTION2. OVER LOAD DETECTION3. THERMAL DETECTION4. POWER SUPPLY DETECTIONSWITCHING MUTE ON MUTE CIRCUIT ONIS FAULT ELIMINATED?NORMAL OPERATIONACTIVATING FUSE BLOW CIRCUITBLOWING PRIMARY FUSEIS CIRCUIT ABNORMAL?ABNORMALNOYESNORMAL OPERATIONNOYESPage-2
Page 2
2.THE CIRCUIT OPERATION OF THE DETECTORSa.DC detector: A circuit operates when neutral voltage at speaker output exceeds DC ±3V. b.Over load : Power supply ±11V for the amp IC7501 is ceased detector and the signal is muted when speaker terminals are shorted. *An over load detector does not blow a fuse. A circuit keeps muting on as long as speakers are shorted. c.Thermal : A circuit operates when temperature on a heat sink detector exceeds 105 degree c. d.Power : A fuse blow circuit operates when neutral point of supply the power supply voltage ±12V, ±25V, ±5.6V or ±12V line exceeds ±0.6V. A fuse is blown immediately without switching mute circuit on. *In case of detecting DC voltage at speaker output, an over load current or excessive heat on a heat sink, the amp circuit is muted by stopping supply of ±11V for an amp IC7501 for two seconds. If the detection signal is eliminated during muting on, the circuit resumes normal operation, but if the detection circuit keeps on, a fuse is immediately blown. *In case of detecting abnormal power supply, a fuse is immediately blown. 3.THE OPERATION OF THE FAN MOTORa.Condition of the fan motor rotating at high speed. 1.A speaker output voltage exceeds 3.8V p-p regardless of loading speakers or headphone. *Position of the main volume is around 10 o'clock. 2.Temperature on heat sink exceeds 95 degree c. *Rotating at high speed caused by detecting thermal detector hardly occurs. b.Condition of the fan motor rotating at low speed. 1.Temperature on a heat sink exceeds 85 degree c. 2.Function is CD or DECK and in playing. *The fan motor stops when temperature decreases to 75 degree c. Page-3