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There are currently no product reviews.
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Exactly what was needed to assess the product - excellent value and great service
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Nice to have the service manual for the Sony DCR-TRV345E now. The document is of excellent quality.
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MACKIE HR824 26 pages English-only Service Manual contains:
1) HR824 technical overview with the description of front and rear panel switches.
2) HR824 specs
3) Block Diagram
4) Wiring Diagram
5) Packaging management
6) Spare part & final assembly list (for PCB rev A and B) + exploded view
7) Test Procedures (where, how to measure voltage...) including Test Point diagram on the PCB.
8) IC and Transistor charts.
Excellent guide: very clear, good scan quality enabling us to print readable diagram :-)
Note:
Mackie HR824 make extensive use of surface mount devices (SMD). Service on the HR824 must
only be undertaken by experienced service technicians with the right tools, experience and patience to perform surface mount rework when needed.
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This Service manual is very well scanned and its clean to read, no any anti-theft words that un-english could understand. I got my CCD600 working with this manual and it´s clear shematics :)
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I was very pleased with the service provided and was surprised at how good the quality was of the manual. I thought it may be a third generation copy or so, but it is as good as the websites that charge 3 times this much. I repair some electronics for family and friends without charge, so this is perfect for me. Thank you very much.
f1723 / FP7317 / L1702 / vf17 / FP17 8. Power Board Operation Therory
8.1 Line filter consists of C801, T801, C802, C803, C804, C837, C838. It eliminates high frequency interference to meet EMI�s requirement. 8.2 Rec & Filter Bridge diode D801 converts AC source into pulsed DC. This pulsed DC is smoothed and filtered by C805. R802 is an NTC ( negative thermal coefficient ) resistor, used to reduce inrush current to be within safe range. 8.3 Power transformer : T802 converts energy for square wave from power source C805 to secondary side to generate +12V and +22.5V. 8.4 Output : The square wave from T802 is rectified by D809, D810, then filtered by C817, C822 to generate +22.5V and +12V respectively. 8.5 Driver : Q803 drive T802 from PWM control of I801 for power converted. 8.6 FB : Negative feedback CKT consists of photo coupler I802 and adjustable regulator I803. It can maintain output voltages +22.5V and +12V at a stable level. 8.7 PWM : 8.7.1 8.7.2 Start : When power is turned on. C807 is charged a 15 volt and a starting current above 40uA to pin 7 of I801. I801 starts to oscillate and outputs a pulse train through pin 6 to drive Q803. OPP : When Q803 turns on, C805 supplies a linearly increasing triangle current through the primary inductance of T802 to the driver Q803, once the peak value of this current multiplied by R811 exceeds1 volt, pulse train will be turn off immediately to protect Q803, T802 from being burned out. 8.7.3 Regulation : If output voltage +22.5V goes up, the R terminal of I803 gets more bias, accordingly photo transistor and photo diode flows more current. The voltage of pin 2 goes up too, making the pulse width of pin 6 to become narrower. So the output voltage +22.5V will be pulled down to a stable value. 8.7.4 OVP : If +22.5V goes up too much, the induced voltage on pin 4 of T802 becomes large also. Suppose that it is over 18 volts, ZD801 conducts, pin 3 of I801 is pulled up over 1 volt. The pulse train at pin 6 goes down to zero, shutting Q803 off immediately. 8.7.5 SCP : If output terminal is short to ground, photo transistor does not conduct, hence Q806 does not conduct either. Then oscillation of I801 is stop, shutting Q803 off immediately.
HPD-K17AA Power Board Block Diagram
Line Filter
Rec. & Filter
Power Transformer
Outpur Rec. & Filter
PWM
Driver
FB
Page 11
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