Elmo ST 800 on the mend.

[Stuart Budd]

New to me faulty ST-800.

As it was sold as faulty I didn't test, just took the back off.

Here is the general location of the faults I found.



There had obviously been some work done here as the screw head (B) centre of pivot had been stripped. There was no spool drive belt but the main drive square belt (A) looked new. (C) is Auto feed release adjust.



The pivot arrangement looked odd and didn't work in any manner. I noted that the fork and tong weren't engaged. The tong of the pivot was this side of the fork. Once engaged in the fork as shown, the penny dropped. I understood the function better.



The adjuster (C) was also the wrong side of the auto release mechanism (D). Once these issues were corrected (as in photo) and slight adjustment made to the Auto feed Release (C). Auto feed function worked as intended. (E) being the pin that locks the Auto feed Green Film Path in position. Auto feed can only engage when main selector is in forward position (lamp off). Off and Project (lamp on) positions will release Auto feed. As shown the mechanism will not lock Auto feed pin, main selector is off.



A new belt was made (bit thick).



Not sure if the screwed gear post is to assist in changing belts as it was loose. But I tightened it and removed the spool arm gear instead as wanted to make a length for the belt in situ.



The internal components done. The fuse required changing. Don't know why it blew.



First test after completion yielded no sound or barely. But getting there.

So this, along with the others that are partially in bits will have my attention over the festive week and a bit.

[Steve Klare]

Good Work Stuart!,

While you are at it, your lube looks mighty thin:

https://8mmforum.film-tech.com/cgi-b...c;f=1;t=009552

(This is good gear lube too: just a swipe on a fingertip across some teeth. Operating the gears should spread it.)

-and your low audio sounds like a classic "switch trick" case.

https://8mmforum.film-tech.com/cgi-b...c;f=1;t=009425

-as always: no guarantee, but always worth a try.

[Stuart Budd]

Thanks Steve. I'll have to get some Super Lube. Been meaning to and now the holidays are here anything by post seems to have a delivery date in 2022!

But yes, nearly every cog and cork is dry. Don't think the first photo shows good enough the feed spool tension spring is almost totally compressed. The takeup spool is very stiff. So I'm glad you noticed the lube lack of. Think inside the arm also has an issue with that.

Tried the phono trick but didn't get sound. Only literally had 5 minutes. But there are directions to follow to assist me now. Will update👍

I have started to digitize the optical film I had from Classic Home Cinema. That's running on auto so doesn't need a supervisor.

I do appreciate the tips and links.

All the best Stu

[Steve Klare]

Hi Stuart,

Please also work the red record key. You may need to be persistent: one member here did twenty reps. before his sound came back!

(To my knowledge, this is a world record!)

[Stuart Budd]

Takeup Spool. It's the belt I made. Took the arm cog covers off. All free. Worked my way to the belt, took that off and no more stiffness. Made a thinner belt and it feels fine. But I also swapped springs, feed to takeup and vise verse. Now takeup can't be bothered to takeup!

Oh! At the start of that test - Sound. Briefly. So I think a coffee is in order.

I will actually run through the audio steps you've mentioned and clean the head.

I did swap the fuses too. One looked odd. The fuse point is a note for me. I will explain.

I'm guessing once I get the hang of the mechanical side of projectors, the electronics will be next! Small steps.

Todo list:
swap tension springs back
audio plugs and switches
explain fuse

[Steve Klare]

I've been using these belts on my own Elmos (including two ST-800s) for years:

https://www.ebay.com/itm/25481415584...wAAOSw0fZdtkOR

I change them roughly at five years of steady use and have never had one fail on me.

-He ships worldwide, too.

[Stuart Budd]

I've just had another play. Got this yesterday and just been going over it and when I was musing over the spool tension I noticed the fly wheel! See top picture. The retaining spring!

I can see why getting second hand can be hit and miss. As time goes, a lot of "untested" "no lead" units will have gone through so many "I'll have a go" guys like me, you may never get a "just needs a belt" "maybe an easy fix" unit in the future. I know this with clocks. They're a marriage of parts.

But I do like to achieve. So put the spring on correctly as a by the way.

Also adjusted belt tension. After shortening it it got tight so used the adjustments to iron out that.

The bump stop and two cog plate screws for adjusting belt tension and cog teeth mesh.

[Joel Bleakley]

Good Stuff Stuart, Just to clarify is the mechanical almost done? It's cool you're doing a systematic approach. I try to do the same but sometimes change depending on when spare parts arrive. Of course we will need a picture of it running once finished. Good luck with the sound. I was curious if you get hiss through the speaker. I ask to get an idea of where the fault lies. Sound issues usually fall into 1 of 2 categories. In the preamp or front section. Like dirty or bad sound head sections. In this case you might get hiss but no sound when running a film. Or the 2 type of fault is in the main amplifier section. In this case there will be no hiss. In the case of Steve's suggestion this can be a common issue with many Elmo projectors. The internal switch that the switched between record and play gets dirty contacts. By running it back and forth can clean the dirt off and restore sound. Good luck and let us know how it goes. Joel.

[Stuart Budd]

Thanks Joel. I will update on all my projects as it's important to list fails as well as triumphs. Janice and Lee spring to mind when offering advice and fixes. Maurice too. Way before joining 8mm Forum I, unbeknownst to me watch a video by Janice on film splicing. Just informative and casual approach appealed to me. Tried and tested methods almost being lost by us newbies and our take on things. Try this, kind of thing. Reality is that something else made it work. If all you have is 5 minutes to find an answer, the web is getting very cloudy. I've almost forgotten about the "Index of Technical Topics - Please Contribute!", a very handy list not to be overlooked.
Belts. They're a tricky subject. How grippy they are to inward force. Too much inward force to gain grip isn't right. Polyurethane cord works but has issues with rewind. May actually need to get that new set after all.
Audio. I've had no hiss but there has been clicks when turning the volume on off. I also had a moment when the red record LED would illuminate. On last check, that is no more.
I'm 3 Jins in on christmas eve, so better not start on more testing. But will eventually.
Some bits are in the post. Maybe New Year for them. But the next few days will have the 800 in a better place 😊
Merry (literally) Christmas