Slide projector drive help?

I have an old Rollei p11 dual format projector that the drive to the slide changer is a bit weak.

the fan which is running continuously has a solonoid operated idler wheel which makes contact when drive is called for

Ive cleaned the idler with MEK (Rubber rejuvenater) but it slips when needed

would you rough up the shaft?

if so what with...wet and dry,emery etc

Its the spindle sticking out from the blue rotor

It would need to be quite coarse so emery paper, rubbed longitudinally so the "teeth" are at right-angles to the idler. Ideally a new idler I think - possibly using an O ring as a tyre on an aluminium hub?

I think I would try a rubber sleeve on the shaft first. It is a reversible option if it does not work.

Martin C

.

Me too

Hellermann sleeve should be good.

https://www.canford.co.uk/ProductResources/resources/H/Hellerman/Hellermann%20Sleeves%20Datasheet.pdf

MichaelG.

Edited By Michael Gilligan on 10/06/2020 17:49:43

IMHO, rather than modifying what you already have, I would try cleaning the shaft first with IPA or methylated spirit to remove any build-up of lubricant or contamination . But I would not try this on the rubber idler as the rubber may expand and loosen when exposed to a spirit based fluid.

Ed.

As a last resort, would heat shrink sleeving provide sufficient grip?

Again, a reversible / replaceable means

Howard

Well after pulling out the drive wheel i had a closer look at it ...it was very hard no compression at all with fingers or teeth!!

is this material called ebonite?

anyway gently rubbed the surface up with 300g emery cloth then again with the MEK

cleaned the shaft as best i could though the drive wheel touches only 5mm from where the spindle exits a oillite bush in the motor and it seemed a lot better...but still could be snappier in operation.

if i helped the solonoid it worked perfectly

checking the voltage to the solonoid it was only 15v dc but if the reverse was used another solonoid pulls in then the voltage drops to 10 v ish

delving into the wiring the motor and lamp are 240v the transformer for the control circuit and focus motor is built into the motor windings...not seen this sort of arrangement before.

the low voltage ac is fed to an old selenienium rectifier then onto the control circuits so i added a 100uf cap on the dc side and now everything works well

cleaned up all the casings which looked rough when i got it off eBay but its cleaned up great and now works fine on the 2x2 side ...just waiting for magazines for the 7x7 side.

Selenium rectifier! Good grief! They don't last forever. Replacing it with a modern silicon diode type would probably fix the problem without the cap.

Deeply envious - I lusted after one of those for as long as I shot transparency film!

Nick

theres lots on ebay

i bought this one for £60 posted.....it came from Ding dong !!!!

not heard of that place

I wanted one for years in the 80sand 90s but they were too rich for me

i also recently bought a rollei twin lens dissolve all in one unit with zoom lenses for less than a 100

Edited By Ian Parkin on 11/06/2020 16:24:58

Unfortunately I haven't shot transparency film in years. I still do some b&w (That always sounds like the anti-drug advert, "I do some film, but I can handle it" ) and some c41 for convenience.

I think the last Fujichrome I shot was 5x4 - I bought 10 sheets just to try and to be able to say I had shot large format reversal, but they havn't moved out of the file since I shot them.

Digital is far better in almost every way except occasionally I remember the fun that film was.