Have you changed the STK4277 yet ? Sounds like you need to.

However this is not blanking the video. You usually don't get snow
without an antenna on Pioneers, but can you get a video signal ? If
you can, you probably need a couple of caps in the IF module. That is
common and I've seen where customers just watch it through a VCR
tuner, for years even.

Don't try to analyze the convergence error. Their circuit is such that
you just must put in a good IC. If the IC is partially shorted, that
probably caused the current failure of the power supply. IR will
probably turn out to be a fusible somewhere.

When you get the STK, there is a suffix, either STK4277L or SL.
Whichever it is get that, otherwise installation will be more of a
PITA. And the heatsink, make sure it is completely clean and apply a
bead running between the mounting holes. Do not prespread it. It is
important with a six channel IC that is pushed pretty hard.

But do tackle the video first, otherwise you don't know if the fix
worked. Thing is now you got sweep, the next thing is video. Run it
with the 4277 removed if necessary, but see a picture.

JURB