TV went off, and three lights come on (green "power", red "temp", and red "lamp")for just a second, in succession from left to right.

Faulty capacitors

Hi,
If the Lamp red light is blinking then replace lamp, replacement procedure is written in user manual and its easy.
If standby/ power red light is blinking then please count its blinking and post here. It is an error code that has info about problem in specific section of tv.
You will see 3 seconds long pause between blinks so count pause to pause.

Check your color wheel. There is a DIY guide for replacing the color wheel. Mine did the same thing yours is and my color wheel was all busted up. Unfortunately after replacing the color wheel my set continues to do the same thing, but this could mean I need to replace the ballast as well.

The color wheel needs replacing. Thats causing the whining and it will also make the lamp light blink.

1) Can be dust do a good clean
2)Check for the fuse and change it if needed.
3) Capacitor needs to be changed, you'll have to findout which one.

Hope it helps, good luck

Here's an excerpt from the Sony Manual online. And the link - http://esupport.sony.com/US/perl/webtree.pl?template=EN&mdl=KDF55XS955&content_id=68&category_id=11&problem_id=52

The POWER/STANDBY (red) indicator flashes three times
If your power/standby indicator is flashing in a pattern of three flashes, this may indicates that the lamp cover is not attached securely. Follow the directions in the Operating Manual under changing your lamp that related to closing and securing the Lamp Cover. Ensure that the Lamp Cover Door is securely fastened by tightening each screw.

The POWER/STANDBY (red) indicator flashes continously
If your power/standby indicator is flashing continuously, and the lamp cover has been secured, your TV may be in need of service.

The POWER/STANDBY indicator is lit up green (not flashing)
A sustained green light indicates your TV is on.

The POWER/STANDBY indicator is lit up red (not flashing)
A sustained red light from your power/standby indicator simply indicates that your TV is in standby mode. This shows you that your TV is ready to be turned on with the remote.

Is it the power light and not the lamp light? If the lamp light is flashing then replace the lamp.

power pack capacitors have failed they will need to be replaced with new ones and that should repair the tv, soldering skill is required to do this or replacement of the entire power pack.
hope this helps

Those blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit section inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power LED, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating procedure, to many popular brand TVs and other devices.
http://electro-medical.blogspot.com/
http://homenol.blogspot.com/
http://electronicshelponline.blogspot.com/
If blinks continue without any pause, the main board is faulty.

The lamp can cause the picture to cycle without spitting out a lamp error. I'd replace the lamp and clean out the dust/dirt from fans, etc to hopefully resolve your issues.

What are the labels on the lights? Timer/Lamp/Service and what color is wich?