8mm Forum: Bell & Howell 33ST Take-up Belt/Gear Won't Turn

This is topic Bell & Howell 33ST Take-up Belt/Gear Won't Turn in forum 8mm Forum at 8mm Forum.

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Posted by Janice Glesser (Member # 2758) on February 14, 2012, 03:04 PM:

I've encountered another strange projector problem...but this time with my Bell & Howell 33ST. The take up reel gear belt will not engage without me manually giving the gear a twist. Take a look at the video to see what I mean http://www.youtube.com/watch?v=4wxvzioaAHI&list=UUzhVuBJou11ziWdERi0ZGuQ&index=1& feature=plcp

It doesn't seem to matter what type of belt I use...I have the original square belt...I've used round and square o-rings of different sizes... AND I've lubed it with white lithium grease, but nothing seems to get this gear going. Once it's going it runs fine...but stop it for 5 minutes and it won't start up again.....HELP!

Posted by Joe Taffis (Member # 4) on February 14, 2012, 03:40 PM:

My 33ST started doing exactly the same thing after many years of reliablity. I ended up junking it [Frown]

Posted by Janice Glesser (Member # 2758) on February 14, 2012, 05:42 PM:

Joe...I don't give up very easily [Smile]

A friend of mine in Australia just happened to watch the video and noticed that when I turned off the projector the tension loosened on the belt. So with that in mind I tried a couple of things which so far seems to have alleviated the problem.

I replaced the #21 square belt with a smaller #20 round belt. I then stacked together 3 adhesive backed pads and wedged them between the outer right side of the gear and the case to help keep the tension of the belt constant when the motor is turned off. I let it sit for 10 minutes and turned it back on and the gear started right up. I'm going to let it sit even longer and continue checking it...but this looks promising. Time will tell [Razz]

[ February 15, 2012, 10:22 AM: Message edited by: Janice Glesser ]

Posted by Janice Glesser (Member # 2758) on February 17, 2012, 01:35 PM:

Well...my fix didn't last long [Mad]

After the machine was turned off for a few hours the gear wouldn't turn without manually giving it a start again. I have loosened the gear up with grease and a few drops of oil...but I'm not sure how freely the gear is suppose to turn. As you can see in the video...once the gear starts turning, it seems very smooth. When I use a #20 o-ring it seems too tight and bogs down the motor...when I use a #21 there isn't enough tension to start turning the gear...so the belt just slips. Does anybody have a B&H 33ST or the 33SR they could look at and give me some feedback. I need to first determine if the gear itself is the problem.

Thanks a bunch!

Posted by frank arnstein (Member # 330) on February 18, 2012, 06:03 AM:

Hi Janice

I think the long plastic worm gear may be binding on its shaft and so is reluctant to start turning. The belt is struggling to turn it and is deforming under load. You must reduce the friction of the shaft inside the gear some-how.

Why not take the worm gear right off and then lube the inner shaft it spins on? Test it in your hand to see if its free to turn before refitting. Grease if needed. Remove Igors adhesive pads at this stage but keep them on standby.

So grease it up, refit and give it another whirl. Make sure the belts and pulleys are bone dry with no trace of oil to prevent pulley slippage and don't fit an overtight belt to the worm gear.

Good luck with it Janice, we will await your report.

dogtor frankarnstein

[Wink]

[ February 18, 2012, 09:40 AM: Message edited by: frank arnstein ]

Posted by Joe Taffis (Member # 4) on February 18, 2012, 09:10 AM:

Janice, I didn't give up easily, I tried many times to fix that stubborn 33ST before deciding that something inside the motor wasn't co-operating. Mine was reliable for many years of constant use, and at the time (pre internet) no spare parts were available, and I still had my CHINON 7500, so I junked it. I have to say I got more than my money's worth out of it. I could have sent it out to B&H for repairs, but for what that would cost it just wasn't worth it.

Posted by Janice Glesser (Member # 2758) on February 19, 2012, 09:51 PM:

OK Frank...I hope I'm not being too pre-mature here. But it looks like for now the worm gear is turning without any manual assistance. I took another picture for comparison to show what I did.

If you look carefully you will see that the worm gear is not one piece. I discovered that to get the gear turning I didn't have to spin it with my fingers...but rather I turned off the projector...using a small screwdriver I widened the gap between the two pieces...turned the projector back on and it would start turning. It appears that widening the gap lessened the presser on the gear shaft.

After several hours of testing it seemed to work 98% of the time (Sometimes I had to run it in reverse first then forward). To help the gear stay in position and to maintain the gap... I added a drop of glue where the two pieces met and I also kept "Igor's Fix" in place.

I'm not sure how long this fix will last. I think it would be better to find a replacement worm gear. A friend of mine in Melbourne has a 3D printer and said he'd make me a new part :-)...but if anybody has a junker SST or SSR out there I would be happy to buy this part to see if it solves the problem for good.

Thanks AGAIN Frank...your feedback was right-on and it helped me to finally make progress after weeks of dead-ends [Smile]

Posted by Jon Addams (Member # 816) on February 19, 2012, 10:44 PM:

Hi Janice,

The Adhesive pads sandwiched between 2 washers (Igor’s Fix) is not a fix, the space between the end gear bracket and the inside back of the projector (about 1/8”) needs to remain empty.

Also the gap between the 2 pieces should fit like a jigsaw puzzle piece, perfect without any gap.

If you turn the shutter manually, does the shaft rotates freely?

Jon

[ February 19, 2012, 11:58 PM: Message edited by: Jon Addams ]

Posted by Janice Glesser (Member # 2758) on February 19, 2012, 11:47 PM:

Hi Jon...I guess you kind of burst my bubble [Frown]

... I was pretty happy to finally get it working. Yes, I agree that what I've done with the gear is not the way it was intended to work...but my goal here was to get it to turn on it's own with the switch.

There is something wrong with the worm gear. It does NOT turn when I move the shutter...only when the machine is powered on and I use the selector switch. Thanks for the picture. If you look at my original pic...it looks very similar although there was still a small gap.

I noticed when I had the two pieces of the gear separated that it turned on the shaft very freely....but when I re-attached the two ends together it seized up alot. I guess my guestion is....How freely is the gear suppose to turn on the shaft?...very freely?...or with some drag?

I've become quite intimate with this little gear over the last few months...repeatedy removing it and putting it back in at least 50 or more times. [Eek!]

If there's something I can do to get the gear rotating smoothly the way it was intended...I'll give it a try. I'm open to any suggestions that would lead to a more permanent solution. Heck at this point I'm will to try a magic wand and some fairy dust. [Wink]

[ February 20, 2012, 03:15 AM: Message edited by: Janice Glesser ]

Posted by frank arnstein (Member # 330) on February 21, 2012, 01:14 AM:

Hi Janice,

Try increasing the backlash between the worm and wormwheel. There should be some free play between the gears and your pic shows very little gap. Jons pic shows a clear gap. These gears should not be pressed up tight against each other. You should be able to slightly move one gear without moving the other. Loosen the 2 phillips screws and allow the gears to move apart a bit. This may help.

dogtor frankarnstein [Smile]

Posted by Janice Glesser (Member # 2758) on February 21, 2012, 02:06 AM:

Jons photo was very helpful. I finally had something to compare to mine. I just got through taking the whole worm gear apart. I should have done this before like you said Frank...but I had trouble getting the clip off the end and was afraid of bending it. I finally got it off tonight. I sprayed some slide-all lubricant on the shaft and put it back together. When the two pieces are put together is does create some drag when it's turned on the shaft. I think this is normal... but it seems to be turning much smoother now. Anyway...I remounted the gear and turned the projector on and it started turning right away....forward and reverse [Smile]

I then read your comment Frank and loosened the screws a bit too. It still seems closer to the worm gear than in Jon's picture...but it's working. The gear still doesn't move when I turn the shutter...Is it suppose to?

I'm going to let it sit overnight and test it again in the morning. I'll let you now how it goes.

Posted by frank arnstein (Member # 330) on February 21, 2012, 03:39 AM:

That sounds encouraging progress Janice.

About the 2 philips screws holding the bracket, I meant for you to loosen them to see if the bracket will slide away a tiny bit. But I didn't mean to leave them loose. Retighten them after trying to increase the gear backlash.

Have you tried a looser drive belt to see if that reduces binding of the gear on the shaft?

dogtor frankarnstein [Razz]

[ February 22, 2012, 12:50 AM: Message edited by: frank arnstein ]

Posted by Janice Glesser (Member # 2758) on February 21, 2012, 09:09 PM:

I've been testing the repairs I've made to the worm gear all day and it's looking very good. It's much easier for me to show you then to write it...so here's the video:

http://www.youtube.com/watch?v=4WawT_ufuOY&feature=youtu.be

Posted by Jon Addams (Member # 816) on February 21, 2012, 11:56 PM:

Nice job Janice --- really nice [Wink]

Let me know when your repair shop is open for business. [Big Grin]

I admire your determination!

Warmest regards,

Jon

Posted by Pasquale DAlessio (Member # 2052) on February 22, 2012, 05:25 AM:

Janice

You are the bomb! I love how you tackle anything and keep at it.

PatD [Big Grin]

Posted by frank arnstein (Member # 330) on February 23, 2012, 04:11 AM:

Clap, Clap, Clap, Clap, Clap, some loud cheering with wolf-whistling & much hooting.
Janice, the whole forum has broken into spontaneous loud applause for you. Igor is even starting to drool from the mouth.

Well done. You have demonstrated to all members here, that you are a tenacious technician who doesn't give up till you get it fixed right.
Your You-tube videos are an excellent way of sharing problems with us and we can all learn something from the interesting cases you present. We need more members here like you.

dogtor frankarnstein [Smile]

[ February 23, 2012, 08:16 AM: Message edited by: frank arnstein ]

Posted by Janice Glesser (Member # 2758) on February 23, 2012, 01:37 PM:

Hooray!!!! Thanks guys for all the very nice complements...made my day!..and BTW...it's still working [Smile]

Here's a celebration video (this is for The Dogtor & Igor) [Smile]

...
http://www.youtube.com/watch?v=FRaqV7A8YQo

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