[old_tv_nut]

Stripes only on the RF output does not sound like a failing power supply. Maybe RF interference from the power supply or some other VCR or piece of gear.

Time to do a process of elimination. Swap out the output cable(s) for another one(s) to check for bad shielding/grounds. Unplug other gear one by one to see if the interference goes away. (Don't just turn them off, as the power supplies may still be running in standby mode.)