I have spent about 4 hours tonight researching several tech sites and the Sony service manual for the same problem with my Sony KV-32HS510 unit. I was able to download the manual from a website http://www.eserviceinfo.com/downloadsm/31649/Sony_KV-32HS510.html
and a TV Repair training lecture paper at http://www.repairfaq.org/sam/tvfaq.htm#tvhvp
These TV sets have a safety feature where it will shut back down if a high voltage is indicated. Unfortunately, the electronics for these safety features are not very reliable and give false indication. Letting the unit sit off lets the capacitors leak voltage as well as cool off. These two factor help with the unit not falsely indicating a high voltage condition.
The D Board seems to be the most common failure component, but a 6 times flash could be an overcurrent/voltage failure from the A, B, or M boards. A 7 times flash is a Horizontal Deflection Stopped error with no additional information given in the manual for a fix. Again, in most blogs, the D Board seemed to the source of the failures.
A refurbished D Board part no. A1300319A can be bought for around $200 with a new board at $550 per the www.partstore.com
site. Then add $100-$200 for an actual TV service technician and you have a repair bill approaching the costs for a new flatscreen TV.
Some tech types posted that they have actually repaired their boards by replacing individual components for around $40. You may find a service shop that can do the same component level repair at the $100-$150 level cost. It turns out that the closest authorized Sony repair shop is 2-1/2 hours away from us. Good luck finding someone close by.
We were able to get our TV to come back on after dozens of attempts and plan to leave it on until it dies all together. I may attempt my own D Board replacement when the time comes.