Dropper don't drop items (resolved)

When items are in the dropper and redstone comparator send's power to a redstone and it creates timer which goes to dropper. Dropper will not send power. But when you destroy a dropper and place it again then only 1 time it will drop.

Video URL: http://www.youtube.com/watch?v=oZ4rv1Gamzc&feature=youtu.be