Yup if the yellow cap on the end of the AC adapter breaks off it will not pull from the battery.
I fixed it by putting a very light layer of crazy glue on the tip of the AC adapter end and then I pushed it into the input on the JVC and held it for a minute. Then I let it dry for a half hour.
It pulled right out with the cap attached to the end. A little crude but it worked 🙂 Now I can use my battery packs again 🙂
Hope that helps.
John