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Power-on Sequence
After the unit is plugged in, the microprocessor responds to a power-on command.
First, the power supply turns on. Second, both fans rotate, then the color wheel rotates,
the ballast and the lamp turn on, and finally the microprocessor un-mutes the audio and
video, completing the power-on sequence. At turn-on, the TV power LED blinks green.
When the picture and audio are un-muted, the power LED changes to a solid green.
However, if the unit shuts down, the blinking green changes to flashing green. The
cause of the shutdown can be determined by counting the number of times the LED
flashes before it begins repeating itself.
The power-on details of a working TV are listed in table 5, showing that each action in
the chain is measurable. Use table 5 to find which step failed.
Action
1. Plug into AC
2. Press Power button
(front panel or remote)
3. Microprocessor's
power-on command is
applied to the AC relay.
4. Two fans come on.
5. Color wheel (CW)
starts
6. DLP light engine L
board receives power
and data.
7. Lamp on
8. Microprocessor is
informed that the lamp
is lit.
9. Microprocessor
responds to the lamp lit
input.
Power-on Sequence
Path
Standby 7Vdc from the P Bd. to
the DG Bd. microprocessor
Microprocessor turns on the
power supply and mutes A/V.
The power-on signal goes
through the chassis lamp door
switch and thermal breaker
before getting to the AC relay.
Micro. uses CW assembly temp
sensor to control fan.
L Board drives the motor in the
CW assembly.
Power supply powers the L
board & microprocessor sends
logic levels to indicator LED on
the L board.
Micro sends a "lamp on" signal
to the ballast assembly.
Micro lights the L Bd's 3
when this command is issued.
Lamp lights up 5 seconds after
the power button is pressed.
Ballast detects that the lamp is
drawing current and informs the
micro that the lamp is lit.
Micro acknowledges the
ballast's "lamp on" information
and outputs a high to L5/pin 8
Table 5
11
7Vdc at P5/pin 9
Power-on LED blinks
green.
Power-on relay clicks.
Surge relay clicks.
(Two relays total.)
a) Lamp fan (large)
b) Power supply fan
Audible whirling sound from
CW left of the ballast.
Two of the four red LEDs
on the L board light up
proving that power and
data are input.
TV power = 0.5A @
120Vac
Ballast powers the lamp.
On the L Bd., the 3rd red
rd
LED
LED lights up = the "ballast
on" command was sent.
TV power = 1.5A @ 120Vac
Output at B2/pin 3:
0Vdc = lamp on
5Vdc = lamp off
1. Power LED turns green.
2. A/V is un-muted.
3. L Bd. 4
Proof
th
LED lights up.
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