I have two proview lp917 that have the following problem: for 3 ~ 5 seconds after power on work normally (power on led green , back light on, no noise from power sullpy board). After that time: : Back light switch off, power light goes yellow and a hisss noise from power board. I have change all low voltage electrolytic capacitor without any success. Any idea?

copied from the manual, available at the kidde website

RED AND GREEN LED INDICATORS This smoke alarm features separate red and green LED indicators. The LEDs indicate the following: GREEN LED CONSTANT ON - AC power is present. OFF - AC power is not present. RED LED - Can be seen through the Push-to-Test button. Blinks once a minute - Indicating presence of a working battery. Blinks once a second - Smoke alarm senses smoke and simultaneously sounds an audible alarm. Blinks once every 10 seconds - Smoke alarm is quieting an unwanted alarm (Model ADC only). (Interconnected system only): OFF - Another smoke alarm in the network has sensed smoke and is signalling this alarm.

Sounds like either there is a bad connection from the computer to the monitor, or the monitor has a faulty power regulator, causing the monitor to overheat prematurely, and shut off.

My question is whether these three LEDs steady light or flashing during normal mode?

If all three LEDs flash, that means NTC sensors failure!

NTC evaporator sensor is placed on back side of battery evaporator and NTC ambient sensor is placed on front side of batery evaporator.
Battery evaporator is placed in freezer compartment.

Dado

Try a reset. Start by unplugging for 1 minute, then plug back in & if still won't restart try the following. If none of the following work, you will need a technician.

Initializing the TV in many cases can remedy a problem.
In the 2006 product line Initialization is now a user function.
Pressing the front panel "INPUT' and "FORMAT"
buttons at the same time activates Initialization. When
complete all user settings will have to be set again. The
table in Figure 4-3 list the User Initialization procedures.
Note: Pressing INPUT and FORMAT is the same as
the Initialization in the Option Menu (MENU-2-4-7-0)
Order Name Procedure Results Notes
1 System Reset Press <System Reset>
on Front Panel
Hardware & TV operating
software reset.
POWER/Timer LED flashes for 60
seconds. No customer settings
are changed.
2 User Initialization
Press <INPUT> &
<FORMAT> on Front
Panel at the same time.
All customer Audio &
Video settings are reset to
factory default.
All customer settings will need to
re-configured.
3 Reset System
Defaults
From the remote, press
<MENU> <1-2-3>
<ENTER>
All customer settings
except V-Chip are reset to
factory default.
Netcommand, Channel Memory,
etc., will need to be re-configured.
SERVICER
PROCEDURE 4 Initialization
From the remote, press
<MENU> <2-4-7-0>*
select "INITIAL" press
<ENTER>
All customer settings are
reset to factory default.
All customer settings will need to
re-configured.
MITSUBISHI RESET / INITIALIZATION CHART
CUSTOMER
PROCEDURES
Figure 4-3
Figure 4-4
LED Indications
The front panel LEDs, refer to Figure 4-4, also assist in
determining the cause of a symptom. Figure 4-5 illustrates
normal LED operation. Figure 4-6 shows the
LEDs response when a problem is detected and indicates
the possible cause.
Power/Timer
Indicator
Status
Indicator
Lamp
Indicator Condition
Off Off Off Off (standby)
Blinking green
fast Off Off Initialization (10 - 65 seconds)
Off Off Blinking
green fast Lamp runs for 1 min after PTV off
Green Off Off Power On
Blinking green Off Off Power On Timer is set
NORMAL LED INDICATIONS
Power LED Status LED Lamp LED Condition
High Temperature - check ventilation air flow.
(Temperature sensor is disconnected.)
Off Off Blinking yellow Lamp cover is open.
Lamp failure (Lamp fails to turn on)
Off Off Red (Lamp turns off after lighting)
Lamp is broken
Off Blinking Red Off Fan Stop
Off Red. Off Circuit failure. (Run Error Code Check)

Three choices. 1. Take it in for repair. 2.Take the top off and remove and clean the pad. 3. Use the following instructions to reset the printer and continue printing. I chose number 3 and haven't had any problems.
These are the instructions which worked for me on my Canon mp470 and has work on many other Canon models:

1) Close the print head cover, and turn off the printer. While pressing the Resume/Cancel button, press the Power button. (Do not release the buttons. The LED lights in green to indicate that a function is selectable.)

2) While holding the Power button, release the Resume/Cancel button. (Do not release the Power button.)

3) While holding the Power button, press the Resume/Cancel button three times, and then release the Power and Resume/Cancel buttons. (Each time the Resume/Cancel button is pressed, the LED lights alternately in either orange or green, starting with orange.) During initialization, the LED blinks in green.

4) When the LED stops blinking and lights in green, press the Resume/Cancel button the 4 times. (Each time the Resume/Cancel button is pressed, the LED lights alternately in either orange or green, starting with orange.)

5) Press the Power button. The LED lights in green, and the
selected function is performed. (When the operation completes, the printer returns to the menu selection mode automatically.)

6) Power off then back on and test.

First place to look will be the power supply section, look for bad caps (bulging tops or bottom seals), the post back what you see so we can guide you further for direction such as voltage checking, see example of failed monitors due to bead caps: http://s807.photobucket.com/home/budm/allalbums

If the power supply outputs are good! Then I would say the back light inverter is bad! If the screen stays black and does not come on.

I have a similar problem.
Switching the screen off (front panel button) and on again after waiting a few seconds fixes it.
This is a recent problem, so I'm expecting it to get worse and worse until one day!!!!!!

Any high switching power supply of the same voltage and amperage rating will work for you. You may have to cut the end off of your old one and wire it to the new one to make it work but don't waste your money buying a specific power supply.
Good Luck!

Most common problem is inverter board.