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Topic: Potts Platter Take-Up Problem

Dustin Mitchell
Phenomenal Film Handler

Posts: 1865
From: Mondovi, WI, USA
Registered: Mar 2000

posted 12-25-2005 05:24 PM

We all make mistakes sometimes Mark. I have a basic knowledge of booth operations (limited to the equipment I've worked with) so to be honest I really wasn't sure if I was right or not [Smile]

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-25-2005 06:37 PM

Christmas shoppers burn out is what I call it.....

You are correct though.... tree drops-platter spins faster till it falls far enough for the micro to shut it off.

Mark

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Patrick Matthews
Film Handler

Posts: 86
From: Kansas City, MO, USA
Registered: Sep 2004

posted 12-27-2005 09:50 AM

I did manage to set the electronic zero based on a manual that I recieved from a tech that does other theatres in this area (i'm running a Potts Alpha platter btw). I also switched out the microswitch down there. It is still doing the same thing. While I could understand that it would be the position of the motors and the rubber on the drive wheels every deck is doing this and I find it hard to believe that they all just stopped working at the same time.

EDIT: I went up just a second ago to try disc timing and I read in the manual to turn all decks to the off position and then raise the take up plate to the lower hole and put in the pin in so it stays in place. I did this and then turned all the switches to rewind. Instead of all the decks spinning nothing happened. I hen lowered the take up plate about a half an inch and they all started spinning. So basically it looks like the center of where my take up plate is supposed to be engaging is lower than it should be.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

posted 12-27-2005 10:29 AM

With the carriage in the lower hole (if you have 2), and the three decks in takeup....pardon me "Rewind," the variac should be adjusted so that the decks creep very slowly. Speed should be less than 6 inches per second.

New platters are adjusted this way so that when threading you put the platter into REWIND, and when the film tightens, the pin pops out and then the motor stops. Louis

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Patrick Matthews
Film Handler

Posts: 86
From: Kansas City, MO, USA
Registered: Sep 2004

posted 12-27-2005 10:55 AM

Fair enough Louis, but they don't creep, they don't move at all. So once again I ask is there an adjustment that i'm missing or just not understanding so that I can make this so? I guess i'm just a little confused.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 12-27-2005 11:18 AM

You may also have a dead spot on the autotransformer

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-27-2005 03:04 PM

I agree... Bad autoformer(variac). Probably a broken statiionary rotor contact on it. The one down near the center of the rotor.... I wouldn't do any more work on it till you take a real close look at the variac.

Mark

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Patrick Matthews
Film Handler

Posts: 86
From: Kansas City, MO, USA
Registered: Sep 2004

posted 12-27-2005 03:52 PM

I obviously don't have the original manual so I'm going off of the closest one I can find in the manuals section. If I'm looking at the right thing it is a black piece right behind the microswitch that has about 8 different wires going into it (sorry, I'm not very technical when it comes to machinery like this). Does this piece need to be replaced totally or is there a part of it that goes bad? If I have to replace the whole thing what is the difficulty and any estimated costs?

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-27-2005 08:15 PM

You can either replace the whole thing or repair it your self. Some dealers stock all the replacement parts for that particuluar Staco variac, model 1010. Brushes, rotor, stator, snap ring, etc. There are tens of thousands of those running daily! We stock all the 1010 parts and I'm sure that some other dealers do as well. New variacs are expensive from the factory but a new off the shelf 1010 can be modified very easily. Check with your local supply dealer or your local electrronics parts house if there's no cinema dealer in your area. Many of our customers swap out the variac themselves and then have the old one rebuilt to serve as a standby unit. No cinema technician in your area and you're unsure about what to do or afraid to work with electricity.... just call in any electrician he'd be able to fix it. Just be sure to print out Louis's instructions on setting the zero voltage point for him.

Or... Perhaps Monte could put together a step by step pict-o-graph of how to replace one..... He's pretty good at that.

Mark @ CLACO

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 12-27-2005 09:33 PM

The only repairable item on a autotransformer is replacing the brush
A dead spot is an opening in the winding and is unrepairable
Often when the dancer oscilates up and down constantly it is an indication of a dead spot

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 12-27-2005 11:32 PM

quote: Gordon McLeod
Often when the dancer oscilates up and down constantly it is an indication of a dead spot

I'm gonna chime in on this one even though Gord here has it right: (a side topic for you with my asking..)

With the "dancer" (that's a new term for me on this unit..I've always called it the "W" or the accumulator...WHATEVER..lol)

oscillating up and down .. is the platter deck bent causing the motor to pivot up and down on its mounting axis? This causes the film takeup speed to variate causing the "dancer" to oscillate up and down.

Cure on this (if this is what it is..)take the deck off, lay it flat on the floor, look at the "spider supports" and see of the "spider supports" are bent any. And if so, take a crescent wrench, close the opening gap to the width of the "spider", place the wrench in the spider and bend the spider supports back to vertical and this will raise that portion of the deck to be flat with the rest of the deck.

I've seen decks so warped that the "dancer" actually jam up to the top of the run and will pull the lower guidance roller on the projector over. Plus, with this variace, the payout deck will speed up and suddenly stop causing thrown prints like nobody's business.

How they get warped is when people hammer the splicer while the splicer is on the deck's edge fixing a break, or they lean like crazy over that part of the deck while threading the brain, or on rare occasions, moving prints by taking the deck off the support arm and moving the deck with the print (especially with huge prints...and I'm guilty on that one, but I make sure the the deck is lifted squarely with a helper and placed back on the receiving arm in the same manner...)

This "bending the spider support arms" to get decks flat is my usual treatment of oscillating "dancers."

Yea, I'm about ready to do some more shoots of "do-it-yourself- fixit tips"

quote: Patrick Matthews
I hen lowered the take up plate about a half an inch and they all started spinning. So basically it looks like the center of where my take up plate is supposed to be engaging is lower than it should be.

The brush arm that contacts the windings on the variac should be close to in the middle of the wind set. I wonder if the microswitch is way out of adjustment, (with the "dancer" all the way down, one motor switch to either "rewind" or "payout" and you barely lift up the "dancer", does this one deck start to take off full speed with the "dancer" raised about 2 inches? If so, then the microswith is adjusted correctly) the "electronic zero" isn't adjusted right...or a burnt spot on the windings itself... You may have to make up your own "electronic zero" to get this unit to function.

-Monte

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-27-2005 11:47 PM

quote: Gordon McLeod
The only repairable item on a autotransformer is replacing the brush

Actually I have only seen one dead spot in a 1010 winding over perhaps 30-40 failed units in 20 years.... but then we also don't have the drastic hydro problems you have up north in some areas.

quote: Gordon McLeod
A dead spot is an opening in the winding and is unrepairable

Not necessarily.... While an open stator is a dead stator the most common failure point I experince on a regular basis is the stationary contact and the ares of the rotor itself in which the stationary brush normally rides on. A missing contact button or broken contact that is still actually making rough contact will eventually arc and erode the brass contact area of the rotor away. This leaves the 1010 with intermittent operation at the common point of platter operation. As Monte said finding a new zero point might get you by... but the same variac is also used in the MUT so you could rob that one temporarily so you can run film. To see if the stationary contact is broken just remnove the cover of the variac and look into the variac between the windings and the rotor with a flashlight... it should be pretty obvious.....

The stationary brush, the most common part that fails is also available from Strong dealers as Strong part number 2103.

All 1010 parts are available as spares from STACO... but they do have a miminum order amount...

The replacement Staco Part numbers are as follows: Tele. # 513-253-1191

Brush set 808-0127-S
Contact plate 808-0147-S
Contact Assy. 841-0025-S
Rotor Assy. 942-0178-S

Hopefully this helps.....

Mark

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 12-27-2005 11:49 PM

Thx Mark for these part numbers, for I need to rebuild some STRONG MUTS, since these "booth clowns" that I have to deal with love to tip over [Eek!]

the MUT at times..

-Monte

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-27-2005 11:55 PM

We stock all the 1010 parts if you need them Monte.... lots of stationary brushes and rotors!

Mark

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Patrick Matthews
Film Handler

Posts: 86
From: Kansas City, MO, USA
Registered: Sep 2004

posted 12-28-2005 09:20 AM

quote: Monte L Fullmer
The brush arm that contacts the windings on the variac should be close to in the middle of the wind set. I wonder if the microswitch is way out of adjustment, (with the "dancer" all the way down, one motor switch to either "rewind" or "payout" and you barely lift up the "dancer", does this one deck start to take off full speed with the "dancer" raised about 2 inches? If so, then the microswith is adjusted correctly) the "electronic zero" isn't adjusted right...or a burnt spot on the windings itself... You may have to make up your own "electronic zero" to get this unit to function.

Monte - Just went up and checked and indeed the microswitch is adjusted correctly, when the dance is about 2 inches from the bottom the decks are going full speed. I was just up messing around with the dancer and when I usually thread it I lock the dancer in with the pin in the lower slot, which usually has the motor engaged and thus the brain paying out while I get me leader through, It no longer does this because this position isn't engaging the motor anymore, but it will begin spinning the decks when I put very light tension on it...not enough to unlock the pin, but enough that I have to push my hand up a little bit.

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