Sony DTV-01, Руководство пользователя

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69
Board Determination
If the standby light does not blink but the unit shuts down, the problem is in
one of the seven remaining areas that were not monitored by IC3251.
Five items are on the D board; two items are on the G board.
First prove the problem is not on the G power supply board with a peak
hold DVM. A conventional DVM (or older one with a slow gate/sample
time) may not be fast enough to measure the full voltage before shutdown.
You will see if the D board is outputting the correct voltage or a shutdown
demand voltage by using the following steps:
1. Latch the front panel master power switch IN (TV on).
2. Plug the set into AC. There should be no sound and the TV is off.
3. Monitor the voltage at CN5002/pin 9.
CN5002
4. Press the remote’s power ON button.
5. 0.3Vdc or 1.3Vdc will be measured.
D board
a) 0.3Vdc (normal voltage from the D board).
means the problem is on the G board. It can be caused by:
= A protection latch (Q5504/Q5503) defect (G board)
=
Exc15 volts from converter 1 (G board)
=
The surge relay did not engage (G board)
Measure the +15Vdc @ CN5002/pin 5 when you power ON the TV
again with the remote. The trip voltage is +22 volts. If the +15V pin
is below +22V, the problem is the protection latch or the parts around
it (surge relay circuit). See the Protection Circuit 1 diagram.
b) 1.3Vdc at CN5002/pin 9 means the problem is on the D deflection
board. You will need to go to the protection circuit 3 diagram for
further troubleshooting now that you have identified the board.
* Complete listings of this TV’s normal operating conditions in different
modes are at the beginning of this book under “Normal Operation”.
Here is a partial list.
The normal sounds at power ON are:
Plug into AC = no sound
When the power ON button is pressed:
1. 2 relays click (3 actually click – AC, surge, & degauss)
2. Degaussing coil thump
3. Frying noise (HV).
When the power is turned OFF:
1. 2 relays click