Announcement

Collapse
No announcement yet.

Bell&Howell 1698 repair help

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Bell&Howell 1698 repair help

    Click image for larger version  Name:	AC79443A-C601-4691-AF5C-63AFC5EE6543.jpeg Views:	0 Size:	145.6 KB ID:	37042 I have a 1698 in mint condition which has had very little use and it has developed a fault where when loading a film and the auto load trips to play mode, a roller should fall to tighten the film loop around the sound drum. It does not fall and consequently the sound drum does not pick up speed straight away, so the sound is distorted until the drum picks up speed. I think maybe that grease has hardened around the spindle that the roller assembly rocks on. Although the assembly can easily be manually moved up and down it is not operating as it should. Has anyone had this problem and how best can it be resolved.
    This is the roller assembly in question and below is a photo of the spindle that the assembly rocks on.
    Click image for larger version  Name:	0FE4D072-E707-4257-99E1-78185426371B.jpeg Views:	0 Size:	127.5 KB ID:	37037
    Last edited by Terry Sills; June 27, 2021, 12:27 PM.

  • #2
    I have not attempted to take apart a TQ3, but watching videos where the worm drive has to be replaced, the entire frame has to be removed. One of the jobs needed to do that is to loosen up the sound block, from that rear side. I don't think it is possible to loosen it from the front but I stand to be corrected, but based on what I have seen its not an easy thing to access, unlike an Elf. Possibly the flywheel may need to be removed. This seizure of the guide rollers is quite a common thing in my experience. Only recently, I have purchased another TQ3 cheaply where this mechanism was like a solid block, with no movement at all, but my plan anyway for the machine was to send it off to 'KB cine' where this fault will be rectified at the same time as the fully intact, but old worm gear, is replaced.
    I shall be looking at this thread closely to see how it plays out and good luck. I hope someone can provide a better answer than I can.

    Comment


    • #3
      Another vote for Kevin, KB Cine repairs, Nottingham.

      Comment


      • #4
        One of my TQI models has stabilising rollers which do not return by themselves after auto thread is released.
        It is then a simple method just to manually return them into contact with the film around the sound drum.
        That is possible only if the rollers are not completely seized which will then be a major job to service.

        Comment


        • #5
          I expect the auto return of the smoothing rollers were a refinement on the TQ3’s. They do work to a degree but are very sluggish which causes flutter and wow for the first few minutes of a film, until the rollers take up the slack and the sound drum picks up speed.
          Not at all obvious how to get to the scissor action of the rollers, but I have tried to oil the mechanism, using a pipecleaner, with a degree of success but really not as good as getting full access to see what’s happening.
          Bell&Howell certainly did not design their machines with owner servicing in mind.

          Comment


          • #6
            Well after some persistent attempts of lubrication it seems that I have resolved the problem and the rollers are working as they should. Very pleased because you don’t see projectors in this fantastic condition very often. When TQ3’s are working as they should they are pretty much unbeatable in performance. Pity that they are so difficult to work on without the right tools and experience.

            Comment


            • #7
              Got the very same problem of stuck roller arm with my B&H. Due to my inexperience in that time (20 odd years ago) I though that fine, just disassembly/lube/reassembly work. Shouldn't take long.
              In the end I spent about a day putting everything back together in place. And just make it barely work, sort of.
              That's one of reasons I eventually sold it away. What a relief!

              Comment


              • #8
                Originally posted by Terry Sills View Post
                I expect the auto return of the smoothing rollers were a refinement on the TQ3’s.
                I understand from a very well-known cine engineer that the auto thread system remained unchanged from the earlier auto-thread Bell & Howell models.

                Comment


                • #9
                  I have never owned a TQ1 or 2, but I was under the impression that the actual 'machine frame' (I think its called) was the same on all three types of TQ's, the manual loading ones having less parts of course. When I watch tear down videos of all three, I can't see any difference. There were some visual design changes on the operating side regarding rollers and sprocket clamps which appear to have been refined during the TQ1 era, fixed and then kept as is for the later TQ's, based on my observations, though I would be interested to know if I am wrong. Those rollers appear to be that they would function on a TQ1 in the same manner as later models.

                  Comment


                  • #10
                    Just to add...I once had a faulty TQ3 where the rollers around the sound drum had to be moved into place manually after threading the film. Even so this did not mean that the sound was right. There was still some 'wow' in the audio though better than not having any roller of course. It proved the point that the drum assembly needs the rollers to not just pinch the film but gently open and close with the force of the moving film, so this must have been allowed for in the earliest TQ design.

                    Comment


                    • #11
                      Well in reply to Maurice and Martin all I can tell you is that on my machine, you push a lever forward at the base of the projector which activates the autoload. You then feed the film into the top sprocket, the film passes through the lacing path until it exits at the rear of the projector. You then switch to off and connect the film to the take up reel. Then switch to forward and the tension from the take up reel automatically activates to play mode without having to do anything manually. The rollers (top and bottom of the sound drum) automatically close down to tighten the loop of film around the sound drum which eliminates the wow and flutter that would be caused by a loose film loop. As I previously stated my projector is the 1698 (optical/magnetic). If other TQ3’s are different I would be interested to hear, but it sounds to me that both Maurice and Martin suffer from the same problem that I had before resolving it - that being that the rollers are not acting as they should automatically.
                      Last edited by Terry Sills; July 01, 2021, 03:43 PM. Reason: T

                      Comment


                      • #12
                        I'm not sure if there were any manual load TQ3's. Early versions of TQ1 were manual so I presume that the rollers were in a closed, but sprung position with the absence of an autoload system?
                        I'm sure Maurice will have the answer!

                        Comment


                        • #13
                          For manual threading I refer you to the 642 for example.

                          The two sound stabilising rollers would be tight on the sound drum. Whilst manual lacing you thread around them and then on to the bottom section of the second toothed sprocket, but only on its edge (not engaging the teeth).

                          Then you give a gentle pull until the the two sound stabilisers pull apart, then gently slide the film onto the sprocket teeth.

                          Sounds complicated, but dead easy when you know how.

                          Comment


                          • #14

                            As an afterthought, here are some details of the Bell & Howell 642, which, together with its brothers, the 641, 643, and 644 were produced in 1962 and were the first manual load Bell & Howells with the new design which featured the dreaded worm.

                            Bell & Howell 642 ~MANUAL THREAD~ 16mm. SOUND PROJECTOR Information Page (ian-partridge.com)

                            Comment


                            • #15
                              Thanks Maurice for the info. I wish there was a manual load like the 642 you describe in a more modern TQ3 form. I do understand your description of the threading on the 642 as I sometimes do it on the TQ3 by following the same procedure. I like to be familiar with the techniques of manual load, rather than rely on the auto load all the time, and perhaps it adds a little more satisfaction to the job of running the machine. The 642 is better around the drum area for manual load as it does not appear to have that guide around it and there is more space to work in. You can still get the film around the drum on the TQ3 without removing the lamp/ guide cover, but its just a little more fiddly.

                              Comment

                              Working...
                              X