8mm Forum: ELMO ST-1200D - Green threading switch is locked all the time

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Posted by Christian Schatz (Member # 2961) on December 30, 2012, 08:48 PM:

Hello,

the next problem on my Elmo. I hope someone can help me with a workaround.
Since today the green threading switch on the front is stuck down all the time.
The black release switch at the back has no function anymore.
I opened the backplate and had a look at the solenoid switch for the front green
switch. If i push the solenoid switch back, the green front switch releases.
But it doesn't release automatically ...

What is the problem and how can i fit it? [Confused]

Posted by Steve Klare (Member # 12) on December 30, 2012, 09:28 PM:

Are you good with electronics?

Sounds like either the solenoid is dead or the voltage that's supposed to make it move is absent.

The best thing to do is hang a voltmeter across the solenoid coil terminals, push the button and see what happens to the meter reading. If it goes up when you press the button it's probably the solenoid. If it's always zero it's something else (wiring, connection, switch contacts...)

Measure this on both AC and DC scales, I'm not sure which this one is...(I'm guessing AC)

Posted by Dino Everette (Member # 1378) on December 30, 2012, 11:30 PM:

Christian, also check the button, as i had a sticky button one time..

Posted by Christian Schatz (Member # 2961) on December 31, 2012, 08:03 AM:

Hello,

the voltmeter was reading something when i pushed the button. I checked the wiring
(blue and red cable) and found a loose connection at the contact switch. I soldered
the blue cable and now the automatic threading works flawless again. I think it
was a bad solder point. I thank you for your help! If i had looked more precisely
at the issue, i didn't had to bother you with such things. [Wink]

But be aware ... the next problem where i need your help is coming surely! [Wink]

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