Help fixing Vector-06c

[x-code]

The checkered picture when turned on is a good sign.
If the boot grid does not appear, the memory may be defective.

But the pattern in the original poster's screenshot does not look like a boot grid at all.
Here's a proper "boot grid" (barring the text at the top that could be different depending on the bootloader ROM version and the filled blocks that only appear when the bootloader is loading byte blocks from the cassette tape):



Even putting the issue with washed colors aside, the first picture does not look like the bootloader has properly started. And the second pic rather looks like there's an issue with h/vsync (which is actually quite possible since Vector-06c has known issues with its video output not being 100% conformant to the standards. Old Soviet TVs did tolerate this, but it's not necessarily true with CRT monitors like the NEC you have)