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Author Topic: Platter Drive Motor Diode Michael West Film Handler Posts: 67 From: Halifax, Nova Scotia, Canada Registered: Apr 2000 posted 02-12-2003 05:49 PM                        Gordon yes that is a relevant concern especially when the diodes have eventually been removed from all three platter feed motors. Paul, your information has convinced me "i will not have anything to do with this" but as for the other guys - well that is up to them. i will document this forum topic for my own protection, have to say this info is of great value for me i do value this web site. i am often seen at this multiplex as over protective and somewhat old fashioned and therefore "not with the team", so i have very little influence but to keep out of enevitable disasters.  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 02-12-2003 08:57 PM                     If the motor came back with "poor results" then they screwed up the motor or it was beyond repair. These motors may not be what I would choose if I was designing a platter, but there are thousands of them working every day - with the diodes. The diodes are not the problem. It may be a 10 cent part but the designer wouldn't have wasted that dime - it's obviously required for some reason. Your description of timing the decks indicates that the tech is not the crunchiest pickle in the jar.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 02-12-2003 09:22 PM                     Dave, right on! I would like to believe their tech is not totally familiar with the theory of operation of the machine.  |  IP: Logged Michael West Film Handler Posts: 67 From: Halifax, Nova Scotia, Canada Registered: Apr 2000 posted 02-12-2003 11:31 PM                        no i won't blame the tech. as we only have one for the entire maritimes and he is very good but over worked as we all are. it is very easy to time the strong platters the manual makes it very clear but no one (i am the exception) seem to see this as being terribly important and what started this was actually when i took and bad motor apart, cleaned and changed bearings and brushes gave it back to them with unsuccessful results so then we sent them to the motor shop and so it goes, i think our problems could be resolved with new motor bearings/brushes cleaning and obviously platter timing - now if only sombody at work would take me seriously hmm. i don't think i would have the time to sneak in and do it myself...  |  IP: Logged System Notices Forum Watchdog / Soup Nazi Posts: 215 Registered: Apr 2004 posted 07-22-2008 10:43 AM                 It has been 1986 days since the last post.  |  IP: Logged Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 07-22-2008 10:43 AM                     I remembered this thread and thought I would reply. I was on the phone with someone from Design and Engineering yesterday. They have been bypassing the diode for a year or so now on the black motors. The funny thing about it is they are unaware of any problems when putting one of the newer black motors on an older strong platter with the grey motors. If I'm not wrong, Strong sent out a memo on this years ago. All the shafts had to be the same size. Well the 3 theaters that have the black motors on them do not take up fast enough on start up. The yo yo drops. I have tried timing the platters with no good results. The newer motors don't seem to have enough power for some reason. It is very easy to stop the platter from spinning with very little resistance. They seem to be puzzled by this. I know that I have heard this in other theaters too.  |  IP: Logged Jim Cassedy Phenomenal Film Handler Posts: 1661 From: San Francisco, CA Registered: Dec 2006 posted 07-23-2008 12:42 PM                     quote: Richard May The newer motors don't seem to have enough power for some reason. It is very easy to stop the platter from spinning with very little resistance. I recently had what I at first thought was a motor torque problem at one of the theaters I'm responsible for. Platter tables did not seem to have enough torque and would bog-down under long (heavy) prints to the point where sometimes the yo-yo thingy would drop and shut everything down. I started checking motors and platter control circuits, etc- - but the problem turned out to be nothing more than old grease gumming up the platter turn-table bearings. I took the platters apart, cleaned out the old grease and properly re-lubricated everything and have had no problems since. Just for good measure, I ordered a couple of spare sets of platter bearings, but I haven't had to use them.  |  IP: Logged Noel Mackisoc Film Handler Posts: 8 From: Newton, NJ, USA Registered: Jun 2008 posted 07-23-2008 02:30 PM                        Be assured, the diode is necessary as Pat Moore states. Rarely will performance improve by shunting it; more often it deteriorates. Probably, Strong replaced the motor itself with a new unit (cheaper than actually replacing parts). Trouble is, the new motors, although very much like the old (grey) ones, do not have the same low-speed torque characteristics and will appear to run much slower, especially when mixed with other--worn--motors. The same obtains if you install a new (black) replacement motor. You can get 'round this by replacing all 3 motors with rebuilts/new and re-time the platter afterward.  |  IP: Logged Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 07-23-2008 03:48 PM                     Why would the company that makes these motors be bypassing the diode on purpose then? This is what they told me over the phone the other day. They said it is not needed. This is coming directly from them. Jim, thanks for the idea but I compared the newer black motor with the older grey one and there is a huge difference.  |  IP: Logged Randy Bowden Expert Film Handler Posts: 146 From: Portland, OR, USA Registered: Aug 2000 posted 07-23-2008 05:49 PM                     The slower speed problem seems to be rather typical of the new motors. We do motor re-cores here at ACE. That involves getting a new ametek motor. I have done the diode bypass experiment in my shop and I did see a very noticeable speed increase with the motor but so far no trials with that in the field. With older platters a good practice is to just re-core all 3 motors.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 07-23-2008 06:49 PM                        The newer motors will gain speed if properly "run in." Not likely to happen on the platter, but seems to happen at moderate speed on my work bench. (less than 1 hour) Louis  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-23-2008 09:06 PM                     What Louis said.  |  IP: Logged Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 07-23-2008 09:21 PM                     I will try it.  |  IP: Logged Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 05-25-2009 05:28 PM                     Just got a new motor from Design and Engineering. Along with the motor was an instruction sheet specifically saying to bypass the diode to increase motor speed. Between the size of the hub and the diode, no wonder it sucks timing these things. Nobody knows the correct way.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 05-25-2009 08:04 PM                        Later, then the motor speeds up and you reinsert the diode. Louis  |  IP: Logged

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