So this DVL 919 I have plays great except when it gets to side B of an LD. After a few seconds, it skips back and repeats. I know this is something to do with the laser reaching the farthest point of movement in its own field and the assembly is not moving forward on the track.

At first I though it was something physical on the track or gearing, but actually I can skip forward by chapter and get it to play the next chapter a few seconds than the skip backward and repeating happens again. So it's a more complicated problem. Now I have a DVL 909 for parts and was wondering if anybody had any idea what needs to be checked or changed to correct this?

clean the gears/rail and put some new crease on the metal top base where the laser runs on

That's a good suggestion which I will do.

But apparently what was going on with the 919 is that the skipback was happening in the first 10-15 seconds of side B and then would also happen at certain points afterwards, seemingly without rhyme or reason. But I saw a pattern in that this skipback happened at the same points on the disc always, within a second or two. After some close inspection, I noticed that the small bent, u-shaped tension flange that presses against the laser assembly worm gear looked to be off a bit, or tweaked. I confirmed this by observing the same piece on a working 909. So I took it off to see the 919 operation without it. I also noticed that the worm gear itself seemed to have a few slightly worn spots where the gear edge seemed to be a tiny bit rounded as compared to the normal edge at other spots.

So putting the player back into operation without the tension flange revealed no more skipback. However the places where there was skipback before now exhibited either a fraction of a second of blanked picture, or a wavy image, or sometimes even a momentary speedup then return to normal. I can only think that the slightly rounded edges of the worm gear are somehow responsible, and that this edge rounding happened because of binding caused by the tension flange, causing skipback, and then the worm gear rubbing against the toothed gear while stuck and whenever the scan forward was used to get out of the skipback lock.

As it is right now without the tension flange, it's working pretty well, more or less. Obviously, replacement of the gearing on the laser assembly will be best at some point, but I'm sure glad it was not a problem with electronics, for there I am lost. Mechanics I can handle.

I know a few years back I changed a Driver IC for the Slider motor that caused this problem, pretty rare though. Usually its the GearHolder, Im sure someone PM'd you on this by now..

Have a Good and Safe Holiday

Im working on a pretty Nice dvl-91 the Cam gear Timing Switches all Broke from shipping a few years back I guess...

Duane, MI

I would trade you your 919 job for the 91 Job any day,

Sorry for your hiccup rixrex !
My dvl 919 has not had that symptom for what it is worth.

Hope you get it behind you sooner then later.
Do you have a repair tech in your vicinity ?

Did have when my Dad was around, but no longer, so it's a self repair situation.

But it's actually working pretty well right now and I have the DVL parts player for when I get around to replacing the gearing.

That's good, and good you have a backup parts player , sounds like the DVL- will make it through the Holiday movie list just fine..

Sounds like you know your way around the mechanism pretty good, as Im the one that sent your customer a part for his dvl-700 a while back at no charge.

You did do the right thing by looking at the track first

As I repaired a DVL- 919 for a fellow, it was a piece of her sewing thread wound around the worm gear on the optics slider motor on the RH side...

Don't ask how it got there

Thanks, the part you sent went to my cousin in Kentucky. So it was just a relative deal which means a lot of work and that's all. Fortunately he has a neighbor good at fixing stuff and replaced the part for him.