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Takahashi EM-200 mount and my eyebrow...

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#1 revans

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Posted 20 August 2009 - 08:34 AM

Hi all,

I've used a Takahashi EM-200 mount for a few years now and am very happy with it. The night before last, I was polar aligning the scope and put my left eye to the polar scope as usual. I felt something like a pin stick into my left eyebrow and realized that it was an electric shock.

The mount has a 12 volt power supply. When I unplugged it, the shock went away. Upon reflection, I think this has happened before many months ago... the little shock is no big deal... but I wouldn't want my mount to crash because of a short or something. So... Tak EM-200 owners... have you experienced this sort of thing???

I notice that when the power supply is on, there is a sort of red glow to the polar scope FOV, although it is not helpful at all. I never bother with illuminated reticles and things like that, preferring to use a flashlight briefly to illuminate the etchings etc.

Anyway, the mount works and tracks perfectly. Is this something I need to worry about?

Rick

#2 Jaxdialation

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Posted 20 August 2009 - 08:51 AM

This has never happened with either my 200 or 400. I would call Texas nautical Repair and see what they say. It is NOT normal.

#3 Dan G

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Posted 20 August 2009 - 03:25 PM

Agree with John - nothing I have ever encountered with my NJP or EM-200. BTW why do you find the illumination for the polar scope not helpful? I love it. Did you know you can vary the brightness using the adjustment screw next to the plugs on the mount?

Dan in NY

#4 revans

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Posted 20 August 2009 - 04:23 PM

I had forgotten all about the adjustment screw...but that would make a difference. I've just gotten into the habit of briefly shining my very small flashlight a bit to illuminate the etchings and do the same thing with all of my finderscopes to see the crosshairs. I do it now almost without thinking... but maybe I should get in the habit of using the illuminator.

I think there must be some grounding problem with the mountm but it works fine. Its almost not worth shipping it for repair, but I will if it persists. The little "zing" is confined to the eyepiece of the polar scope area... and it isn't present anywhere else on the mount or the scope and is really minimal.

Rick

#5 revans

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Posted 20 August 2009 - 04:28 PM

Hmmm... come to think of it... maybe the problem is actually with the power supply box and not with the mount...

Rick

#6 TxStars

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Posted 21 August 2009 - 04:52 AM

There is an LED on the underside of the electronics board for the polar scope.
If it got bent over somehow causing one of the wires to be be up against the motors or something it could short and cause the dim red glow and the shock you are getting.

#7 revans

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Posted 21 August 2009 - 01:25 PM

Hmmm... sounds like a possibility... how do I access the board with the LED?

Rick

#8 skyler

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Posted 21 August 2009 - 01:59 PM

Hi Rick -

Just take the Temma control box off of the mount with the 4 corner screws on the box face. Some are on tight so be careful when unscrewing not to strip the heads. They are a smaller philips/slot combo design. Once you get those off and BTW they are very long, then you can pull out the box which has the PCB attached to it and on the back side you will see the long LED legs. I am short on the mem but I think they have no insulators on them as noted. Just be sure when you put it back in, that you check the fit/placement. They can get tangled in the wiring harness and get bent into a really poor position where it will appear suddenly you have no illumination at all. Just a heads up on that since I have done it on a different mount before.

Good Luck and it is a really easy process. Plus you will get to see the neat insides of your mount as well.


S

#9 revans

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Posted 21 August 2009 - 02:17 PM

Thanks, I'll give it a try this weekend...

Rick






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