KP-46WT510 is blinking 8 times repeatedly on standby what is the problem?

Low B over voltage or over current shutdown its usually related to either the A board or the B board. You can get the replacement A board which includes the B board from www.tvrepairworld.com

Let me know model and brand of TV if its other then Sony KP-46WT510 and also count red standby light flashes as there would be long pause between blinks.
These info will help me to find out possible solution.

The buzzing sound you hear is typically the FBT shorting out when you turn the TV on. If you open the back panel and watch the FBT as you try to turn on the TV you can see it shorting out. It will be obvious.

Youre flyback is defective.Its an easy repair your flyback is 145328551 which is no longer available but the substitute flyback is thats available at the following link and they provide free tech support with instant messageing so you can replace the flyback yourself. You need flyback 145328511 you can get it at this link with free shipping also. I use them all the time they are a good company with qiuality parts and free tech support.
http://servicemanuals.vstore.ca/

8 blinks on your model number means High Voltage error. Which means TD8005 is faulty on the D board.If you need any additional info please let me know

go to www.iwaynet/~nesda/SonyBlink.html for more info

IF I REMEMBER CORRECTLY THAT IS A LAMP THRMOSTAT

IC1509 8-759-593-33 IC LA78045 35.98
Q1505 8-729-423-33 TRANSISTOR 2SC3311A-QRSTA
Replacement part
8-729-119-79 TRANSISTOR 2SC2785-FEK-HFE 1.02

these ic locations are different than yours but same part number.
is there a 2sc3311 near by LA78045?

Four blinks is a "vertical stop error" I have a pdf file of the service manual and troubleshooting guide. If you want it,let me know where to send it.

I can't directly suggest a solution to this problem. but here is a link URL may be useful to you. http://getmanual.ru/tv/sb/sonyus.htm all the best