Hi,
I have a few old VCRs. I use one with my new UHD 49" Samsung TV that has NO AV input.
I bought a AV to HDMI converter from Amazon.
ISSUE:
Sometimes, when I switch the source to the HDMI with the VCR (HDMI converter) to watch a tape, the picture has poor contrast when I play a tape. Note: At first, there is NOISE due to the VCR's analog tuner.
SOLUTION:
Change the VCR's signal source from it's tuner to AV. I have a Comcast cable converter with AV output. I use a short cable from the converter's video output to the VCR's video input.
John