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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.
CIRCUIT DESCRIPTION
Setting the batteries or AC adaptor (see figure 8) When setting the batteries or AC adaptor, the voltage VDD2 is always applied to RAM and CPU since Q6 and IC5 are turned on. Power on sequence (see figure 8) When the power switch is turned on, PON signal is being H (PON = VDD2). CPU knows to turn the power switch on, it provides H from VCON terminal to base of transistor Q5. Then both transistors Q5 and Q4 are turned on, the voltage VDD1 is applied to all devices. Power off sequence (see figure 8) When the power switch is turned off, POFF signal is being H(POFF= VDD2). CPU knows to turn the power switch off, VCON signal and base of Q5 will be L. Then both transistors Q5 and Q4 are turned off, Q4 stops to supply the voltage VDD1. Power down sequence (see figure 8) If the voltage across the batteries lowers and the terminal DPW of CPU comes less than 4.5V, VCON signal is L. Then both transistors Q5 and Q4 are turned off, Q4 stops to provide the voltage VDD1. Print sequence (see figure 8) When the PRINT button is pressed, TCON signal is H. Then both transistors Q2 and Q3 are turned on, the voltage VP for printing will be 12V.
12.0V 12.0V
Q6
5.0V 5.0V
Q3 Fuse
12.0V 12.0V 11.6V 0V 11.6V 12.0V
11.3V 12.0V
IC5
11.3V 12.0V 0V 0V
5.0V 5.0V
VP (+12 V) VDD2 (+5 V)
Q4
5.0V 5.0V 5.0V 0V
VDD1 (+5 V)
+
+ +
12.0V 12.0V 0V 0V 0V 0V 4.6V 4.6V
4.4V 5.0V
Q2
4.8V 0V
0.1V 5.0V
Q5
0V 0V
GND
VDD1
VCON DPW IC1 PON VDE TCON ON POFF
CPU
OFF
Power Switch Note : The voltages around transistors mean as follows; Upper figure : Power ON at no operation. Lower figure : Power OFF. Figure-8
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