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Great PDF easy to read good info needed for replacment of belts and assembly and specs.
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complete and unabridged very good quality
easy to download.
recieved in two days.
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Awesome manual. Complete diagrams of all board assemblies as well as how to get to each part of the t.v. down to the individual screws and their locations. Get it.
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perfect copy, im very satisfied, i was need the diagram over the powersupply and
the copy was very sharp
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This is exactly the service manual I needed.
Complete with all schematics, partslists, PCB layouts and alignment instructions.
This manual covers both the T-4970 en T-488F Onkyo tuner.
FLOW CHART NO.6 FLOW CHART NO.9
NO YES YES Is the supply voltage 5V feed to pin(3) of IC1706? Does take-up turn when the capstan Check disk and reel drive unit. YES motor is running? Is voltage more than about 2.6V applied at NO Check between pin(46) of IC1701 and all the way YES IC1706? up to pin(2) of IC1706. Are pulses applied at pin(2) of IC1701 when NO Check take-up reel sensor and all the YES take-up reel disk is turning? way up thru to pin(2) of IC1701. NO YES Is the supply voltage feed to pin(21) of IC1706? Check PC 12V line. YES
The cassette tape fails to eject. The drum motor fails to run. Is the voltage more than about 2.6V DC given out Check IC1701. Does capstan motor start when the EJECT NO See FLOW CHART NO.8. NO Check PC 5V line.
button is pressed? pin(46) of IC1701. <The capstan motor fails to run.>
NO
NO
Is a "H"(about 4.7V) level applied at pin(12) Check pin(90) of IC1701. IC1706 when a reel pules has been inputted? Check or replace drum motor. NO NO NO the loading motor.
YES
Is the voltage about 10V sent out pin(15) of IC1706? Check IC1706. FLOW CHART NO.10
YES The drum motor runs only for a few seconds. Replace IC1706.
Is specified voltage applied at loading Check between IC1706 and all the way up thru to NO motor terminal? Is drum PG signal given out pin(7) IC1706? Check pins(4), (5), (6) of IC1706 and periperal circuits.
YES NO way up thru to pin(66) of IC1701. YES
Dose the motor run? Replace loading motor. Check or replace drum motor.
NO
YES
Replace cassette cam, gear, etc. Is drum PG signal given out pin(66) IC1701? Check line between pin(7) of IC1706 and all the
FLOW CHART NO.7 NO
NO Replace IC1701. Does power control(H) signal at pin(4) of IC1701 Check IC1701. YES
No power is turned on. Is V-H.SW.P pulse given out pin(23) of IC1701? Check IC1701.
change from "L" to "H" level? NO
45
No head switching pulse. Does base Q1951 change from about 5.0V Check pin(4) of IC1701 and all the way up thru
NO
YES FLOW CHART NO.11
4.5V? to Q1952.
YES Is the drum motor rotating? See FLOW CHART NO.9, 10
NO <The drum motor runs only for a few seconds> NO
NO
Is sent out collector of Q1951? Check Q1951 and the STBY 5V line. YES <The drum motor fails to run>
FLOW CHART NO.8
on pins(66) and (65) of IC1701, respectively? D-FG D-PG
NO About 5Vp-p Check PC line. Is the supply voltage 5V feed to pin(8) of AC
The capstan motor fails to run. Is the PG and drum FG signal present Replace IC1701.
Is the voltage more than about 2.6V DC given out Check IC1701. YES pin(29) of IC1701.
YES
connector? Are the PG drum FG signals present on NO Check line between pins(7), (8) of IC1706 and all
the way up thru to pins(65), (66) IC1701. YES pins(7) and (8) of IC1706?
Is voltage more than 2.6V DC sent in NO Check between the pin(4) of AC connector and all YES AC connector? the way up thru to pin(29) of IC1701. Check periperal circuit of IC1706. NO
YES
Is approx. 3.5V applied to pin(3) AC Check the pin(92) of IC1701. connector? NO
YES
Is applied to pin(5) of the AC connector Check AT 23V line. normally?
YES
Replace capstan motor.
DV-NC55U/C/M
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