Old projector - belt replacement - advice needed please - UK Vintage Radio Repair and Restoration Discussion Forum

Karen Smyth · 25th Oct 2021, 7:46 pm

Old projector- belt has disintegrated so have bought replacement belt but can't work out how to fit it - - there is a shaft running through and need to know which part to release to get the belt on - are there any knowledgeable projector fans out there who may be able to assist please? TIA

wd40addict · 30th Oct 2021, 8:53 am

What is hiding under the plastic to the left of the transformer? Can you take another photo with the plastic lifted up?

Karen Smyth · 30th Oct 2021, 2:53 pm

Thanks, I've attached a couple of photos

wd40addict · 30th Oct 2021, 3:43 pm

Ok, looks like a bearing on a bracket so not so easy. Clearly some dismantling will be required to get the belt in, but since I'm unfamiliar with this model I can't give any specific instructions.

TonyDuell · 30th Oct 2021, 4:34 pm

I've repaired a few cine projectors and often fitting a new drive belt is not trivial. I recently did a Bolex Multimatic, and the main drive belt is one of the first things to go in the chassis, before the gate and the very complex loading mechanism.

mark_in_manc · 30th Oct 2021, 6:10 pm

I don't know if you'd get away with it - but this type of belt:

https://www.ebay.co.uk/itm/292347783...oAAOSwF71hEj2e

- which comes in all different cross-sectional diameters, is very elastic and forms very stong joints by cutting a length, and sliding the two ends off two sides of a red hot knife, immediately pushed into each other and carefully held until it sets - a few seconds. Then you carefully trim off the excess. So for this kind of job, you could form the belt on the machine, on the bare shafts and not the pulleys to give you some length to play with - which might save a whole load of dismantling hassle.

Not a clear explanation, and not an easy thing to do in close proximity to the machine, but I hope you get the idea!

vidjoman · 30th Oct 2021, 6:49 pm

It looks like there’s a clutch in the drive and it may have some clearance when moved so there might be enough clearance to get the belt through. I have to admit that most projectors I’ve done did involve some dismantling.

Lucien Nunes · 7th Nov 2021, 7:27 pm

As above, no specific familiarity with this mech.

If the housing / bracket of the rear mainshaft bearing can be unscrewed from the chassis, then it looks like there is room to work the belt past the other obstructions. Check whether the front bearing is spherical (self-aligning) because if so, it is sometimes possible to swing the shaft slightly away from the chassis without having to remove anything else. Obviously take great care not to bend / force any components of the intermittent. There will probably be an optimum position to which it should be rotated to give maximum freedom.

If it hasn't run for a long / unknown time, do make sure all the lubrication is attended to before putting into service.

25th Oct 2021, 7:46 pm	#1
Karen Smyth Diode Join Date: Oct 2021 Location: Manchester, UK. Posts: 2	Old projector - belt replacement - advice needed please Old projector- belt has disintegrated so have bought replacement belt but can't work out how to fit it - - there is a shaft running through and need to know which part to release to get the belt on - are there any knowledgeable projector fans out there who may be able to assist please? TIA Attached Thumbnails

30th Oct 2021, 8:53 am	#2
wd40addict Octode Join Date: May 2009 Location: Stevenage, Herts. UK. Posts: 1,518	Re: Old projector - belt replacement - advice needed please What is hiding under the plastic to the left of the transformer? Can you take another photo with the plastic lifted up?

30th Oct 2021, 2:53 pm	#3
Karen Smyth Diode Join Date: Oct 2021 Location: Manchester, UK. Posts: 2	Re: Old projector - belt replacement - advice needed please Thanks, I've attached a couple of photos Attached Thumbnails

30th Oct 2021, 3:43 pm	#4
wd40addict Octode Join Date: May 2009 Location: Stevenage, Herts. UK. Posts: 1,518	Re: Old projector - belt replacement - advice needed please Ok, looks like a bearing on a bracket so not so easy. Clearly some dismantling will be required to get the belt in, but since I'm unfamiliar with this model I can't give any specific instructions.

30th Oct 2021, 4:34 pm	#5
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Old projector - belt replacement - advice needed please I've repaired a few cine projectors and often fitting a new drive belt is not trivial. I recently did a Bolex Multimatic, and the main drive belt is one of the first things to go in the chassis, before the gate and the very complex loading mechanism.

30th Oct 2021, 6:10 pm	#6
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,874	Re: Old projector - belt replacement - advice needed please I don't know if you'd get away with it - but this type of belt: https://www.ebay.co.uk/itm/292347783...oAAOSwF71hEj2e - which comes in all different cross-sectional diameters, is very elastic and forms very stong joints by cutting a length, and sliding the two ends off two sides of a red hot knife, immediately pushed into each other and carefully held until it sets - a few seconds. Then you carefully trim off the excess. So for this kind of job, you could form the belt on the machine, on the bare shafts and not the pulleys to give you some length to play with - which might save a whole load of dismantling hassle. Not a clear explanation, and not an easy thing to do in close proximity to the machine, but I hope you get the idea! __________________ "The best dBs, come in 3s" - Woody Brown

30th Oct 2021, 6:49 pm	#7
vidjoman Dekatron Join Date: Jun 2013 Location: East Sussex, UK. Posts: 3,326	Re: Old projector - belt replacement - advice needed please It looks like there’s a clutch in the drive and it may have some clearance when moved so there might be enough clearance to get the belt through. I have to admit that most projectors I’ve done did involve some dismantling.

7th Nov 2021, 7:27 pm	#8
Lucien Nunes Rest in Peace Join Date: Apr 2008 Location: London, UK. Posts: 2,508	Re: Old projector - belt replacement - advice needed please As above, no specific familiarity with this mech. If the housing / bracket of the rear mainshaft bearing can be unscrewed from the chassis, then it looks like there is room to work the belt past the other obstructions. Check whether the front bearing is spherical (self-aligning) because if so, it is sometimes possible to swing the shaft slightly away from the chassis without having to remove anything else. Obviously take great care not to bend / force any components of the intermittent. There will probably be an optimum position to which it should be rotated to give maximum freedom. If it hasn't run for a long / unknown time, do make sure all the lubrication is attended to before putting into service.