jvc hr-s9800u

[sctig]

Sorry... don't know where else to put this topic

I recently purchased a hr-s9800u vcr used.

On playback, it has horizontal banding, i.e. on the tv screen there are 10 horizontal regions of good video separated by black/gray lines.

Would this be the heads. If so, is it possible to clean these yourself, or does it need to be taken to a JVC authorized service.

[davideck]

Does the banding appear on ALL SP tapes?
During play, does the picture appear to be playing at normal speed (as opposed to too fast or too slow)?
As you view the picture and search forward and reverse at various speeds (2X, 5X, 7X, etc.), does the number of bands change?


If so, the Dynamic Drum may not be functioning properly.

[sctig]

Thanks for your quick response. I've tried 3 SP tapes now and the banding occurs on all 3 of them. My cheapie JVC HRA592U has no such problem, so it must the VCR.

Yes, banding size seems to change as the tape is sped up or slowed down.

Is the dynamic drum the 2" diameter (approx) drum located right behind the tape in the middle of the player? There seems to be a whirring/high pitch hum coming from that area. Seeing as I just got this unit, I'm not sure what would be considered normal, but it seems a little off to me.

If it is the drum, any idea on what would be involved?

[davideck]

The Dynamic Drum is the rotating drum that the tape gets wrapped around. I think you have identified it correctly.

The "dynamic" part involves a motor that automatically adjusts the tilt of the drum as a function of tape speed in order to avoid the banding that you see. It sounds like the drum is stuck in a fixed tilt position that does not allow normal playback. VCRs without Dynamic Drum have fixed tilt drums that produce banding during search but not during play.

If the whirring/high pitch hum is not from the normal rotation of the drum, then it may be the dynamic drum motor constantly running as it attemps to change the tilt. Perhaps a gear is broken.

This sounds like an expensive repair.