Hs-u54 vcr has snow on video

Head amplifier circuit/module could be the problem in your case. You could also check the power supply to see if any electrolytic caps are out of tolerance or have changed value and replace them if necessary.
~
Here are a couple of examples of similar VCR issues I've had; some years ago, I had a Panasonic NV-F70A, with snowy video playback, and, after a lot of investigation and exhaustive testing it turned out to be the video head amplifier module that was the problem (not the heads themselves which were new) - replacing the plug-in aluminium-cased module fixed it and restored the video picture as well as the stereo audio output and flying head erase. Power supply was OK and the whole VCR good to go.
~
With another Panasonic (NV-J11A), it was several out of tolerance electrolytic capacitors in the power supply (another metal-cased plug-in module) that caused the snow on screen, erratic tape counter, and slightly wobbly audio. Head amp was OK in this one. I replaced every electrolytic in the PSU - and after plugging the module back in and turning the VCR on, the playback picture and tape counter were soon restored to normal - after some soak-testing, the machine went home.

You may not need to do anything to or with your machine's power supply at all but it doesn't hurt to check anyway so that you can rule it out as a possible problem source.