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Great quality copy, right what I was looking for, all I need to fix my radio.
Thanks
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I BOUGHT A PAIR OF INFINITY VINTAGE SPEAKERS THAT REQUIRED TO BE REPAIRED AND THE ELECTRONIC TECHNICIAN ASKED ME FOR THE SERVICE MANUAL.
I TRIED TO GET IT AT THE MANUFACTURER'S SITE WITH NO SUCCESS, SO I STARTED TO LOOK FOR IT IN THE WEB FOR A LONG TIME, UNTIL I FOUND THE SERVICE MANUAL IN THIS EXCELLENT SITE "OWNER'S MANUAL.COM".
NOW I HAVE MY SPEAKERS WORKING AND ENJOYING THE MUSIC I LIKE.
THANKS TO "OWNER`S MANUAL.COM" I RECOMMEND THIS SITE TO EVERYONE.
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Very quick response. Very good and accurate print quality of the scanned document.
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The service manual was very usable and clear enough to see the individual values of all of the components (unlike some of the service manuals I have gotten in the past from web sites similar to this one). The price was right and the information was greatly appreciated. It helped me with an otherwise very difficult repair. It was much needed and appreciated. A faster turn around on my order would be nice, but I understand the constraints on your staff's time. Thank you for your service.
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Excellent manual. Helped me out with disassembling and troubleshooting my projector.
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
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