Look what I found- Jig-RCU!

[drzapp]

I've had a web crawler looking for the PTU94023B for over a year, and a few months ago, I got a hit on a site in the Netherlands. They would only mail it to EU countries, for some reason, but I have a good friend in Germany, so I had them send it to her. She then sent it to me- took 3 months for this process, but it is finally here and it works! Now I can do the final dynamic drum adjustments after a rebuild.
*happy dance*

[latreche34]

Keep us posted with your findings here please, Can you share the manual for DD adjustment? I've been looking for one for years, I've never found it in the service manual, at least the models I've owned.

[drzapp]

It is in a few I have, this is the most complete description I found, in the 9800u service manual section 3.2.3 (attached).

[latreche34]

I've seen that before, I was expecting a detailed mechanical adjustment. Why would you want to re-adjust the DD system? have you replaced the video drum or any gears in the DD system, Otherwise there is really no need to mess with the adjustment especially if the gears are cracked.

If you have taken the gears a part, first a mechanical adjustment is required to balance the left and right screw gears before you do any electronic adjustment to the DD motor. So that there is no slack or overload on the bottom of the drum.

[drzapp]

Yes, I am taking the DD apart and replacing or repairing gears. I already have the mechanical adjustment figured out- I just mark where everything is before taking it apart, seems to work well enough, but still some noise that could be cleaned up with the Jig.

[latreche34]

Do you have the stair step JVC alignment tape for that test?

[drzapp]

I do have a stairstep alignment tape, not sure if it is from JVC.

[latreche34]

No one made dynamic drum, it's either a JVC tape or a tape from another manufacturer for a different test, Be careful when you use test tapes, Always use the right tape for the right test by checking tools part numbers or you will be setting off of wrong frequencies.