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Author Topic: Three time's the curse for a Norelco AAII vertical shaft Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-09-2010 10:11 AM                     quote: Tony Bandiera Jr There is no other reason for so many repeated failures in such a short time. 100% operator negligence. Tony, Apparently you did not read my post above. There is indeed a possible problem with the way the replacement shafts were installed. Keep in mind that THIS IS NOT A HARDENED SHAFT! I have only met one or two other techs over the years that were aware of the following... If the bearing retainer plate on the center bearing bracket is not loosened before installing the shaft you can end up with a very slight bow in the shaft. This in turn can lead to galling of the shaft where it passes through the bore of the intermittent drive gear as well as the shutter compensator bores. I've seen this happen several times over the years where the tech was not aware that the bearing bore on the center bearing bracket is over sized to allow for self alignment when mounting the shaft at the top and bottom. It is made this way because there are sometimes slight machining differences in the bearing brackets. Tighten the retainer plate screws back down after the shaft is mounted in the machine. BE sure gear mesh is proper... too loose and you will strip the tops of the teeth right off. Been there seen it happen and over 50 DP-70 rebuilt by yours truly! All the locations around here that have used DP-70 which accounts for close to 40 screens all bump the motor switch when they thread. This is certainly bad for any projector but doing so isn't going to make the gears fail. These projectors do not jump to speed in a half second... more like 3 to 5 seconds to speed. What can make them fail are nasty on off on off power bumps when the shutter is rotating in excess of 2880 RPM. Mark  |  IP: Logged Bill Enos Film God Posts: 2081 From: Richmond, Virginia, USA Registered: Apr 2000 posted 06-09-2010 01:57 PM                     Ran one of these things one time for one shift, was told about this issue, no problem, however, it seems to me that prudent engineering would have included some sort of mechanical interlock to prevent gate opening while the machine is in motion because it undoubtedly happens a lot more often than most people think. Centrifugal devices require speed to function but some sort of torque clutch would have worked.  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 06-09-2010 03:11 PM                     quote: Mark Gulbrandsen Apparently you did not read my post above. There is indeed a possible problem with the way the replacement shafts were installed. Apparently you did not read all the way through my post Mark. I did read what you posted, and if the shaft were installed improperly (which I agree with you can happen) then you would most certainly HEAR the improper mesh of the gears. The AA is the most quiet and smooth machine on the market and if any part of the drive train were misaligned, especially with that huge casting acting as a sounding board, you would know right away that something wasn't right. As an RCA service tech I had about 20 screens of AA's and the ONLY time I ever had to do any major work on any of them was when the operators were being stupid, including bumping the film down with the motor. And I did indeed discover the retainer plate issue, because my first repair I didn't align it as you posted and found out when I turned the motor on for the test run. A quick call to my mentor and he pointed me in the right direction.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-09-2010 08:34 PM                     quote: Tony Bandiera Jr then you would most certainly HEAR the improper mesh of the gears. Actually I've found that in just about every DP-70 I've rebuilt with used parts as John would have done by transferring shafts over run considerably noisier until the gears have run in for a number of hours... usually about 16 to 18 hours (Can also be true of Simplex X-L's!). However, if you use all new gears they run quiet from the get go. The old gears including the steel gears have wear marks and patterns worn in them and they have to re-seat to the other used gear with different wear patterns before things get down to the normal purr the DP-70 makes. The shutter gear pair in particular can be very noisy, actually making a grumbling sound for quite some time because there is basically no loading between the two and seating or run in takes even longer. Mark  |  IP: Logged Thomas Hauerslev Master Film Handler Posts: 451 From: Copenhagen, Denmark Registered: Aug 2000 posted 06-10-2010 02:49 AM                        Time for some history: http://www.in70mm.com/dp70/library/story/index.htm  |  IP: Logged Per Hauberg Jedi Master Film Handler Posts: 883 From: Malling, Denmark Registered: Jul 2000 posted 06-10-2010 03:11 PM                        Hi, Mark When You are doing the big job on a DP70, with NEW gears. Do You get those gears still from Münich - or are You able to make them in Your own workshop ? (Read: Do You have to...) ---------- As it have been mentioned several times, DP70 seldom makes mistakes by itself. On my two old things, there are no other emergency autostop than the original one over the upper loop, which I've allways considered to be enough. But once, I've experienced true disaster due to a spool tower suddenly stopped (fuse blown). There is no electrical connection between the tower and the projector, and therefore, of course the DP70 continued to run. Digital sound from penthouse made no fuzz and picture was fine - ergo I sat still in my seat in the auditorium - until the projector could not get rid of more film downwards and it began packing around the intermittent. Polyester film outside, fiber wheel inside. The rest is logic ! Of course, the main dump in this play is me, sitting in the auditorium instead of beside the projector. Whats puzzles me is, that the "rejector plate" (don't know the right english word for it) for me to see was not out of place, but eitherway, there were several meters of film aound the intermittent wheel, and it stood very still, while the inside wheels and the motor went on. I do believe, I've seen it do better. This was really hard packed and difficult to get out. One new fibre wheel and a replacement (renovated) intermittent unit came out of Münich, the Kinoton-tech was in Denmark the next day as usual, when I have trouble (Bravo !) As John Walsh tells, the fibre wheel was only half-way stripped. But such external coursed mishaps - and projectionist screwing up - for me are the only ways to stop the worlds very best projector. They are getting old and somewhat quirky, yes. But so am I, and they still do their job every day. Two more months now, and they are fifty ! How many DLPs will live to see that ?  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-10-2010 05:32 PM                     New gears over here come from Kinoton USA. No problem getting them when needed... which is very rare... Mark  |  IP: Logged

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