Elmo Sound ST-1200 audio problem

[Anna Weyhrich]

Hello!

I bought an Elmo Sound St-1200 Super 8 projector sometime in the last 12 months, and am having problems with the audio output. No matter if I use Film Guard to clean the film beforehand or adjust the tone/volume knobs while a reel is playing, it always outputs the audio in a chipmunk tone.

Does anybody have any suggestions as to what could be causing this or how I can fix it? I was advised by the seller to let the Elmo warm up with the lamp on high for about 5 minutes to fix the issue, and that solve worked once. Now I can let it “warm up” for 5-10+ minutes and there is no difference in tone.

I have tried several different Super 8 reels on it that all have audio, but the results in tone remain unchanged.

Any suggestions would be enormously helpful!! I can post a video of the audio and picture movement if that would be beneficial.


Thank you!
-Anna

[Steve Klare]

Hello Anna,

Welcome!

The good news is there is probably nothing truly wrong with your machine. The better is it shouldn't be hard to make it right.

The ST-1200 has an AC motor, which runs slower or faster depending on the line frequency of the electric power it is plugged into. In order for Elmo to sell these machines all over the world, they provided a two step motor belt pulley system to compensate for the difference. There are two major frequencies used worldwide: 50 and 60 Hertz. For 50Hz countries, the pulleys are set up to run the transport mechanism 6/5 as fast as the setup for 60Hz. In North America we use 60Hz, so if your motor belt is on the 50 Hz. belt path your 24 Frames per Second becomes almost 29: more than enough for Chipmunks! (What on EARTH do Chip and Dale sound like?!)

If you look at the pulleys, the motor belt sits on one of two parallel sets of sheaves. Yours is probably sitting on the one with the bigger motor pulley sheave and you need to move it to the set with the smaller motor pulley sheave and readjust the tensioner. There is a smaller belt up top: if I remember right this one has to swap sheaves with the motor belt to make room.

New belts are usually needed to revive one of these: maybe somebody put yours on without understanding this problem.

(May THIS be the biggest problem we have today!)

Good luck!

[Anna Weyhrich]

Update-

Hi Steve,

When I took a look at the belts, the motor belt was unfortunately already on the 60Hz motor pulley sheave. Perhaps tension needs to be set better? I cannot figure out how to readjust the tensioner, do you have any suggestions for me to do that or to try something different?

Thanks!
-Anna

[Maurice Leakey]

Click below to see belt position for 60Hz or 50Hz.
ST1200HDOWNER.pdf (film-tech.com)

[Steve Klare]

Thanks, Maurice!

It was kind of hard to explain that without some kind of diagram. (Page 40)

It is still possible to find your "nearest Elmo dealer" as the manual recommends, but they haven't the slightest clue what to do with your motor belt! ("We make...THESE?!")

[Anna Weyhrich]

Click below to see belt position for 60Hz or 50Hz.
ST1200HDOWNER.pdf (film-tech.com)

Thank you, Maurice! I will check that out and see if it can help me

Haha, I will see if I can find any "Elmo dealers" in my area, thank you!

[Anna Weyhrich]

Hello Anna,

Welcome!

The good news is there is probably nothing truly wrong with your machine. The better is it shouldn't be hard to make it right.

The ST-1200 has an AC motor, which runs slower or faster depending on the line frequency of the electric power it is plugged into. In order for Elmo to sell these machines all over the world, they provided a two step motor belt pulley system to compensate for the difference. There are two major frequencies used worldwide: 50 and 60 Hertz. For 50Hz countries, the pulleys are set up to run the transport mechanism 6/5 as fast as the setup for 60Hz. In North America we use 60Hz, so if your motor belt is on the 50 Hz. belt path your 24 Frames per Second becomes almost 29: more than enough for Chipmunks! (What on EARTH do Chip and Dale sound like?!)

If you look at the pulleys, the motor belt sits on one of two parallel sets of sheaves. Yours is probably sitting on the one with the bigger motor pulley sheave and you need to move it to the set with the smaller motor pulley sheave and readjust the tensioner. There is a smaller belt up top: if I remember right this one has to swap sheaves with the motor belt to make room.

New belts are usually needed to revive one of these: maybe somebody put yours on without understanding this problem.

(May THIS be the biggest problem we have today!)

Good luck!

I posted a video of the audio/picture as well as the front of my projector on my YouTube channel:
https://youtube.com/shorts/UEGYvPkpV8s?feature=share

[Steve Klare]

OH!

I didn't realize you are showing home movies!

These may have been filmed at 18 Frames per second (cheaper: uses less film), and your projector may be set for 24 FPS (Which is the speed commercial motion pictures are usually projected. )

There is this large, switch-looking thing on the back side of the machine that says "18" and "24". (It's not really a switch.) If it's set to "24", flip it to 18 and see (well: "hear") what happens.

I live less than 10 miles from Elmo's US national headquarters: may as well be on Mars for all the help they can provide!

[Maurice Leakey]

A little reminder about the speed selector.
The motor must not be running when this is operated.