This is topic Elmo ST-180 Variable Speed Modification in forum 8mm Forum at 8mm Forum.

To visit this topic, use this URL:;f=1;t=005336

Posted by Jon Addams (Member # 816) on March 14, 2010, 10:03 PM:

Today I completed variable speed modification on two Elmo SC-18 using Dual Gang 50k Pots, The variable speed is working great on both.

Does anyone here know if the same pot will work on the Elmo ST-180, if not a 50K pot, any idea which one will do the trick?

Thank you

Posted by Steve Klare (Member # 12) on March 14, 2010, 10:39 PM:
Hey Jon,

This is one of those multimeter times we were discussing a few weeks back.

If you measure the resistance between the wiper and each leg of the pot currently installed, it will give you a pretty decent idea of the value there now.

Since there can be parallel resistances on the board that will throw your measurement off, you might not get an exact number, but if you see numbers adding up to only a couple of hundred ohms for example, it's not going to be a 50K pot. Same goes for numbers in the hundreds of thousands of ohms and more.

In the tens of thousands....maybe so!
Posted by Jon Addams (Member # 816) on March 14, 2010, 11:17 PM:
You always come to the rescue Steve, thank you.

I was thinking about taking that reading but I wasn't sure. Now I can do it with confidence.

Thanks again,

Posted by Rick Skowronek (Member # 385) on March 16, 2010, 01:27 PM:

Here's a chunk of the Elmo ST600D schematic which I believe (forum please correct me if I'm wrong) is the same as the 180D.
Shows you the wiring and values for the speed control pots. May help (or not)
Posted by Martin Jones (Member # 1163) on March 16, 2010, 02:26 PM:
That's for the early versions; there is another using an IC for later models. I have both circuits if they are required by anyone.

[ March 16, 2010, 03:47 PM: Message edited by: Martin Jones ]
Posted by Jon Addams (Member # 816) on March 18, 2010, 12:33 PM:

I would like to have a copy of those circuits and if you can sent them by email to jaddams55 at hotmail dot com, I would appreciated it very much.

Also, how can I tell which is an early or later model?

Thank you

Posted by Steve Klare (Member # 12) on March 18, 2010, 02:09 PM:

I have no schematics at all for my ST-800, and If I had the ST-180 schematic it would probably apply at least in part.


[ January 16, 2018, 07:56 AM: Message edited by: Steve Klare ]
Posted by Martin Jones (Member # 1163) on March 18, 2010, 02:22 PM:
Emails sent to both of you, gentlemen. I just hope I interpreted you email address correctly Steve.
Posted by Jon Addams (Member # 816) on March 18, 2010, 03:01 PM:
Hello Martin,

I received the schematics. Thank you for the super fast delivery.

Posted by Steve Klare (Member # 12) on March 18, 2010, 03:19 PM:
Spot on, Martin!

Why just say something straight out when you can be cryptic?

(I'm a government employee, you know...)

Posted by Torstein Bore (Member # 6262) on January 16, 2018, 07:17 AM:
Hello you 8mm experts!
It’s an old thread this one, but maybe you are still there and willing to help me?

I’m trying to do a variable speed modification on a Elmo ST-600.
I thought I knew how to do it but found that the circuit of the speed regulation pcb does not match the schematics I’ve found.
Now that I found this thread I realize that the version of my MEC-16 pcb is a later one and it looks like some of you might have the correct schematics for this circuit.

Are any of you willing to share this diagram with me?

If you also have a suggestion to how I could do the modification it would be very much appreciated, but I guess I can sort out something if I have the circuit diagram.

Posted by Mark Todd (Member # 96) on January 16, 2018, 07:22 AM:
Van Eck do a fairly cheap bolt on option for them.

Best Mark
Posted by Torstein Bore (Member # 6262) on January 16, 2018, 07:55 AM:
Thanks Mark!

That could be a solution but I guess I have the components I need in my drawers if I just get hold of the circuit diagram.


Visit for free equipment manual downloads. Copyright 2003-2019 Film-Tech Cinema Systems LLC

Powered by Infopop Corporation