Posts: 287
From: Poughkeepsie, NY USA
Registered: Jun 2010
posted July 18, 2018 04:07 PM
Anyone familiar with this projector? I want to know if the pulldown claw has one tooth or two. Also, there seems to be three potentiometers for speed adjusting and it seems to need a tricky balance between all three to get both 18fps and 24fps. Any information would be greatly appreciated.
Posts: 4554
From: New York, NY, USA
Registered: Jun 2003
posted July 21, 2018 11:08 AM
William,
I'm not very familiar with the 8000, however I'm curious about your fps question. Is the 18/24 switch not working properly at either setting, or when adjusted correctly for one speed does not work at the other?
Doug
-------------------- I think there's room for just one more film.....
Posts: 421
From: none of your business
Registered: Jun 2017
posted July 21, 2018 01:38 PM
It would be highly unlikely imo to have three potentiometers for two speeds. Doesn't make sense electronically.
The last time I saw a thread like this it was for a sankyo with electronic speed adjust (two pots one for each speed) and the chap adjusted the bias for the record amp by mistake, as the pots look similar.
Posts: 287
From: Poughkeepsie, NY USA
Registered: Jun 2010
posted July 21, 2018 08:37 PM
At one time, the pots were adjusted to achieve 20fps for film transfer. Now neither speed is correct when the 18/24 switch is set to either position. One pot seems to affect the 18fps setting, one seems to affect the 24fps setting and the third pot seems to affect both. All three pots are side by side in a small opening at the lower front of the projector below the lens. They are only accessible when the front cover is removed.
Posts: 318
From: Burnaby, B.C. Canada
Registered: Feb 2017
posted July 23, 2018 12:45 AM
Interesting thread. I've heard them referred to as trim pots. Potentiometer is the term I am familiar with regard to the Sankyo Stereo 800, they are accessible by removing the rear cover and the two potentiometers are located at the front of the projector on an IC board. The top one can be adjusted to alter the speed at 18 fps. The bottom the same for 24 fps. Very helpful knowledge I found. Can be very useful for film transfers and even re-recording but will not equal sync pulse.
Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007
posted July 24, 2018 05:51 AM
William You can obtain a service manual from Oldtimer Cameras, here in the UK. I am sure that such a manual would answer your questions. https://www.camera-manual.com/model.php?modelid=2583
Posts: 1006
From: West Midlands United Kingdom
Registered: Aug 2011
posted July 24, 2018 06:57 AM
I wonder if they were thinking of putting a variable speed control in it like the SS1200, and ditched it at the last moment .....
Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007
posted July 25, 2018 10:43 AM
That's bad news William. However, I searched through our site's postings and found a member who said:- "My Chinon SP-330MV has three speed pots. One only changed the 18fps, one changed the 24fps, and the third one had an effect on both." Does this comment help you in any way?
Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003
posted July 25, 2018 11:48 AM
Bill,
Does the manual have a schematic in it?
Some (Eumig) often included them, others (Elmo) didn't.
I don't have one of these, but I'd love to know what that third pot is for!
From Maurice's quote it sounds like an adjustment of the reference voltage that the 18 and 24 are being regulated against, but I don't know why they would want to do that: it's overthinking the plumbing!
-------------------- All I ask is a wide screen and a projector to light her by...
Posts: 287
From: Poughkeepsie, NY USA
Registered: Jun 2010
posted July 25, 2018 04:01 PM
I think what Maurice quoted from a previous post is correct. I can tell you that the left pot adjusts the 24fps speed, the center pot adjusts the 18fps speed and the right pot seems to have an affect on both. That's why my initial post spoke of a 'balancing act' between all three. These three seem to need to be adjusted in just the right way. Otherwise, the speeds are off and jitter-free film transport is also compromised.
Posts: 287
From: Poughkeepsie, NY USA
Registered: Jun 2010
posted January 01, 2019 09:15 AM
Frank, thank you for solving this mystery. Your explanation makes me breath a sigh of relief. When you say 'rewind' do you mean actually rewinding from the take-up reel to the feed reel or do you mean projecting threaded film in reverse?
[ January 03, 2019, 10:21 PM: Message edited by: William Olson ]