My current vegetable garden has been inherited from the family who lived in our house before us. When I took it over it was incredibly overgrown with weeds and the only thing that was growing otherwise was a huge patch of raspberries. Not well taken care of, very overgrown, about 3 ft wide by 12 ft long.
After some googling and finding some How to videos by a guy on YouTube I started thinning out the dead canes. At the end of the season I cut the remaining canes back to ~2 ft above the ground.
This season the canes came in beautifully! Everything was super green and lush and I had high hopes for jam and scones. Even with all this growth, I can count on 1 hand the number of raspberries I have gotten from this patch.

As the season has worn on, I got buds and flowers, but rarely the blossoms actually became fruit. I did get quite a few partial berries but that's about it.
I've been somewhat diligent about watering as I know a dry spell can halt production. I also know that the soil I'm working with is sub-par. Overall I have been treating them with a less is more approach but it's obvious I need to do something to save them or I'm not getting any jam!!
I've been trying to upload pictures but it keeps telling me the file is too big. So try to imagine normal healthy looking raspberry canes mixed in with canes that have green leaves around the main veins and the rest of the leave fading to pale green/yellow.
Nutrient issue?? Please help!