Read Sony TA-DA9000ES Service Manual online
17
(ii) Voltage for the video circuit
(P.25, P.34)
When the VIDEO function or OSD is activated, the power switches (Q803 and Q805) are
switched by the serial data output (IC2601 37-pin) of the main system controller and decoder output
(IC2461 2-pin), and voltage for the video/OSD circuit is supplied.
(5) Detecting AC voltage
(P.34)
When the plug is unplugged, the abrupt drop in AC voltage is detected by Q13 and the main
system controller (IC2601 78-pin), and the quitting process such as data backup and muting process
starts.
Also, IC831 and IC833 detect the drop in output voltage from the power transformer, and the
signal is output to the output controller (IC1800 15-pin). The output controller (IC1800) switches the
relay and blocks the speaker output.
(Important) Notes when the power amplifier is broken
(P.25, P.34)
When the power amplifier circuit is broken and a large current flows to +V1/+V2, the regulators
(Q87, Q838, Q808, and Q839) for the power amplifier may also break. In such a case, the power
amplifier breaks again if only the power amplifier circuit is fixed.
Voltage of about 70 V is input to the regulators for the normal power amplifier, and 7- to 70-V
voltage is output according to the volume. Even if the volume is reduced, when voltage of about 70
V is output from the regulators, replace the power amplifier to prevent the regulators from breaking
and shorting internally.
(Important) Checking fuses
Check that fuses are included in the parts that output signals from the main power transformer
(T1).
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