Film-Tech Forum ARCHIVE: AP3 platter problem

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Posted by John Walsh (Member # 168) on 01-20-2004, 05:07 PM:

I have a problem with an Strong AW3 platter; hoping you guys can help. The platter was working OK until a few days ago. The problem is; Whichever deck is used for payout, that deck runs slow. The takeup is OK.

I've tried several different payout heads (the 'new' phase control type) - same problem. I thought the varic may have a dead spot in it, so I replaced the entire varic assembly - same problem. I tried lowering the motor position, which speeds it up. But I need to lower it so far, it barely touches the deck, and the film wraps at startup because there's no torque. And since every motor acts the same, I don't think that's the problem.

I feel it must be a voltage problem, since it happens with every deck. I've measured 25v on the varic. If I press down on the takeup carriage assembly, making the varic voltage go up, the platter runs OK. Also (strangely) the platter will run OK if I flip the feed caster on the unused deck to make it think it's taking up.

Thanks for any suggestions!

Posted by Gordon McLeod (Member # 33) on 01-20-2004, 07:03 PM:

check the trimmer for the calibration of the payout head

Posted by Brad Miller (Member # 2) on 01-21-2004, 12:16 AM:

Not to be nitpicky, but do you mean AP3?

Posted by John Walsh (Member # 168) on 01-21-2004, 10:39 AM:

Yes, sorry, it is an AP3; I have Christies on the brain....!

Hi Gordon; I don't think it's the payout head... several of them do the same thing.

Posted by Daryl C. W. O'Shea (Member # 1303) on 01-21-2004, 08:10 PM:

If they're all about the same age, Gordon's most likely correct.

Posted by Mike Pennell (Member # 1692) on 01-22-2004, 02:00 AM:

We had the same problem awhile back, im trying to remember exactly what we did to rectify it. To get by we hung a weight from the pulley system which in turn increased the tension to the take up and sped up the payout. Hope this helps, when i go in tomorrow ill look at the platter and figure out what we did to solve it. [beer]

Posted by Michael Schaffer (Member # 1204) on 01-22-2004, 03:47 AM:

Since you even replaced the variac I am sure you also made sure it is set correctly as described in the manual? Sometimes it helps to "turn up the volume" on the hub a little.
Regarding the trimpot on the control plate - does anyone know what measurements should be read when the phase mask is fully open?