Toilet tank won't refill

[tom23]

Hi,

After flushing, the water filling the tank is barely a trickle.
I turned off the valve, and left it for hours, turned it back
on, then it flushed and refilled fine twice in a row. Then it
went back to a slow trickle. Does it sound like this is as
simple as replacing the internal workings?
Thanks very much for any help.

Signed, Oh So Unhandy

[Sylvan Tieger]

If your fill valve is a 400A replace the disc