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Author Topic: Vertical Jitter (SRD/CP500) Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 01-28-2005 07:13 PM                        I've got a Vic 5 and CP500D. I've just installed a new computer in the booth for digital slides, and I put DRAS on it, to see what it did. A newish print in good condition tracks at an average error rate of 6, which seems a little high to me. The thing that DRAS complains about most is the vertical jitter, which is frequently in the red (>3 mil). The manual said that this was likely to be equipment related. What exactly is causing it? I thought it might be that the film wasn't tight enough around the sound drum, but I see no way of getting it any tighter. I tried shifting back and forth a few sprockets, but that just changed the size of the loop under the gate, without changing the jitter rate on the display. Any suggestions that anyone has would be gratefully appreciated.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-28-2005 07:53 PM                     What you don't say is if you have a basement or a penthouse reader If it is the basment style check the scnnaer bearings and the rollers also the damper the vic 5 basement usually tracks very well  |  IP: Logged Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 01-28-2005 08:09 PM                        Sorry, I forgot about that. It's a basement reader, mounted just above the exciter lamp house. I've checked the rollers that press down on the rims of the sound drum; they're fine. I'm wondering that perhaps it might be a side effect of the tensioning device that's mounted after the sound drum; instead of the hydraulic dash pot that seems to be standard, there's a manky little sprung roller assembly. It looks cheap and unfunctional.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-28-2005 09:06 PM                     The cinemecanica sound head often had the dashpot damper as an option so maybe someone did a home brew  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 01-29-2005 05:59 AM                     The spring type is far more common than the hydraulic here. Check that the lay on rollers and their pivots assembly haven't siezed up, also when did anyone last oil the scan drum bearings (Assuming it's the older type with the oil point?) Also check the slip clutch asembly on the back of the draum shaft, at the flywheel end, common source of wow and flutter!  |  IP: Logged Matt Zeiner Expert Film Handler Posts: 146 From: Windsor, CT USA Registered: Sep 2003 posted 01-29-2005 08:58 AM                     Sounds a bit out there, but I have seen several V-5's with mechanical oscillations causing excessive jitter in the original basement reader with the lightpipe and remote mounted exciter lamp. One or both of the belts may be too tight/ too loose, setting up an oscillation. If you have a scope, you can see the jitter on the right-hand "goalpost." Tension adjustments to both belts have helped in this case. Try it.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-29-2005 11:19 AM                     post a pix as i havent seen the spring type  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 01-29-2005 11:51 AM                     Most of the V-5 units I worked had the cheaper double roller on a spring dampen pivot arm. Ouside of what Pete and Gordon have noted is that you can also get jitter if the outer bell of the sound drum has been removed for service or cleaning and properly not seated when remounted. I have also seen problems when people have dropped the end bell on the floor and distorted the film riding edge.  |  IP: Logged John McConnel Expert Film Handler Posts: 118 From: Okmulgee, OK USA Registered: Nov 2003 posted 01-30-2005 01:23 PM                        To digress momentarily from the subject, who makes a Dolby Digital basement reader for a V-5? Thanks.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-30-2005 03:25 PM                     funny cinemecanica does  |  IP: Logged Thomas King Expert Film Handler Posts: 119 From: Sheffield, Yorkshire, England Registered: Oct 2004 posted 01-30-2005 06:10 PM                        Pete: I couldn't see any sign of the slip-clutch you mentioned, all there is under the flywheel cover is a bigish flywheel. I dismantled and throughly cleaned the lay-on roller assembly (which was really horribly sticky). It seems to have made some difference: tonight's film ran through keeping the tensioner about a mil from the stop position, which was an improvment. I'll run some SRD film through to look at the jitter. I'm just wondering: how does one go about lubricating the sound drum shaft? I can't see any way to get to the bearings.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 01-30-2005 08:22 PM                     quote: Thomas King just wondering: how does one go about lubricating the sound drum shaft? I can't see any way to get to the bearings. Across the shaft cover, being the housing, there should be a dimple looking device at the middle. This is where you take a small oil can, press down the dimple ball and this let's oil down to reach the end bearings. Cine V-5's had to have this area oiled on a regular basis, or situations like this arises due to the simplified soundhead version of the V-5's. For the simplified version do not have roller bearings, but just sleeve bearings on each end. -Monte  |  IP: Logged Dan Harris Film Handler Posts: 86 From: Bristol, UK Registered: Jun 2003 posted 02-01-2005 04:59 PM                     Gordon, for info here is a (brand new) Vic 5 with spring dampened roller assembly. Oh, and basement SRD reader too!  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-01-2005 05:02 PM                     Interesting is that factory or an add on? All I have ever worked with had the hydraulic damper  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 02-01-2005 05:29 PM                     The spring damper is mounted on a plate which has holes to match the mounting screw holes normally used for the oil dash pot damper.  |  IP: Logged

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