Film-Tech Forum ARCHIVE: Clutch issue (?) on Cinemeccanica Victoria 5 tower-system

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Posted by Luke Capitani (Member # 6018) on 01-03-2011, 03:20 PM:

Hello All,

I'm trying to get to the bottom of an issue, for which any help would be greatly appreciated.

I'm running a Cinemeccanica Victoria 5 tower-system, and during screenings of older 35mm rep-prints (ie. prints that are 10 years or older - new prints never present any problems), I have found that rewinding usually results in the film breaking at some point (ie. the film itself, not a weak splice). I've usually put that down to a combination of the print-age and a possibly stiff clutch on the playing-side (I've had this looked at, but the callout engineers insist there's no problem). However, now I've just had a few instances of a print snapping during recent screening. Should I put this down to stiff/overtight clutch mechanisms in both the take-up AND rewind motors, the angles of the rollers taking the film from one side of the projector to the other, or is it both of the above combined with the general and unavoidable risks of showing older 35mm prints?. Both reels are on opposite sides of the projector with runners taking the film up and over the lamphouse, and through the film gate, so a few rollers at 90-deg. plus might be possible tension spots also.

I realise older prints present greater risks of failure (the print in question had a few other projectionists attempts at resplicing in and around the same 'problem areas' so I guess these were weak spots), but I was wondering if there was any way to decrease the risks of films breaking through a few adjustments on the projector.

Any suggestions would be gratefully recieved, and if I can't do the work myself, I can at least report a correct diagnosis to a callout engineer.

I'm fairly new to projection (sum total of 3 years of experience, and half of that being self-diagnosis when problems arose) so please excuse any lacking knowledge/bad terminology on this.

Thanks

Posted by Rick Raskin (Member # 1561) on 01-03-2011, 04:39 PM:

When you inspect the film are you finding any notched or torn sprocket holes? It sounds like its a combination of a worn print and the angles encountered during projection on your system.

One of the tricks us oldtimers used to do was to put a twist in the film when inspecting so that any weak splices or torn sprockets would cause the film to break. We believed it was better to break on the bench than in the machine. And, it would have required a repair splice anyway.

Posted by Gordon McLeod (Member # 33) on 01-03-2011, 09:13 PM:

That tower was noted for snapping acetate prints if one was not very carefull setting the clutches up

Posted by Monte L Fullmer (Member # 2797) on 01-04-2011, 01:00 AM:

How I would set a clutch up on those Tower/V-18 big reel systems is like the adjustment on the cone drives on the lower magazine of the Simplex XL Deluxe setup:

You get a full reel and place it on the lower spindle. You loosen up the slider lockdown bolt and turn on the power to that spindle. When you have the correct inch pounds of tension on the end of the film when you move the slider is when you lock down that bolt so the friction device in the spindle cone is at the right tension for takeup.

..maybe this will help ... - Monte

Posted by Gordon McLeod (Member # 33) on 01-04-2011, 06:02 AM:

It is important on thoses systems that the clutch felt be in good condition and properly saturated with clutch fluid
also check the dashpot on the hold back

Posted by Luke Capitani (Member # 6018) on 01-04-2011, 12:29 PM:

Thanks for all suggestions so far. Sounds like I'll need to get an engineer to adjust and fully inspect clutches during next service and have a look at the tension issue.

On this note, if there are any projectionists out there that have contacts for any good UK-based cinema engineers, those details would be greatly appreciated. I'm currently trying to find someone who can do a decent service at a competitive rate.

Adding twists to the film on the bench sounds like a good, simple solution to finding any weak spots until the projector's fully sorted out. I hadn't thought to try that out.

Thanks again for all the suggestions.