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odd - possibly - gimbal issue?


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#1 kurt nolen

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Posted 26 February 2013 - 07:26 PM

I just had the gimbal replaced on my frankenstein rig and I'm finding that if I statically balance the sled smart side out, and then pan it 180 degrees with the lens now facing backwards and let go of the sled, it's balance has now changed and it rocks back - aiming the lens upward - to the point that my level will actually slide off the stage. 

 

any thoughts as to cause?

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#2 kurt nolen

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Posted 26 February 2013 - 07:26 PM

for some reason the pictures won't orient correctly but you get the idea. 


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#3 kurt nolen

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Posted 26 February 2013 - 08:02 PM

Figured it out: gimbal's likely out of calibration. 


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#4 Brant S. Fagan SOC

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Posted 27 February 2013 - 10:02 AM

Your gimbal is not centered and your post is likely out of round as well.  Most, if not all, aluminum posts are by nature not truly round unless they were centerless ground during manufacture.  When combined, these conditions will make it challenging to make it pan flat.  What type of gimbal do you have?


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#5 Kyle Wullschleger

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Posted 02 March 2013 - 10:33 AM

Brant - I pulled my steadicam out today, with a 3A gimbal, to do a prep before traveling to Florida for a shoot and noticed this exact same issue. 

 

Is there anything I can do on my own to fix it?  Does something need to be taken a part and reset or is the gimbal a goner once this issue arises?

 

Thanks for any advice you or anyone else can offer in this situation.


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#6 Brant S. Fagan SOC

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Posted 04 March 2013 - 08:51 AM

Kyle--Your 3A gimbal is in need of a shop service and new bearings.  Not something you could likely handle without a machine shop with precision measuring tools.  If you would like to schedule a service, please contact me off-Forum via email and we can go over details.


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#7 Victor Lazaro

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Posted 08 May 2013 - 06:07 PM

Hi, I noticed the same issue on my Zephyr gimbal today. when balanced one way, then flip the rig, there is a +4 deg difference in the angle around the gimbal handle axis. Is there a way to quick fix it myself, at least temporarily? I'm in NYC and a factory service will be a big pain... Thanks for your help.

(PS: I called Derek Hester at Tiffen and waiting for his answer tomorrow)


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#8 Alan Rencher

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Posted 09 May 2013 - 01:01 PM

Adjusting the gimbal is easy. It's just two screw's, but without some know-how, you might end up causing more harm than good.
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#9 Victor Lazaro

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Posted 10 May 2013 - 09:37 AM

I've found this thread http://www.steadicam...showtopic=11595 that lead me to this document http://www.steadicam...alCentering.pdf


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#10 Alan Rencher

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Posted 24 May 2013 - 06:02 PM

That PDF was very useful. My Zephyr gimbal went out of center yet again, and I followed the instructions to align it. Worked great! FYI, you need a #6 spanner driver to make the adjustment (which I happen to have already... I used to work construction.) 


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#11 Frederic Sturm

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Posted 31 July 2013 - 09:38 AM

Hi,

 

Yesterday I received my "new" actually 1-year old used Zephyr from a nice gentlemen from this forum. Its in nice shape, and its a nice rig, I'm pretty

sure it was the right decision to upgrade to, and I'm looking forward to putting it to work.

 

Now, on my first tests I discovered it didn't hold the horizon so well when turned 180° and remembered the gimbal centering document I had read

some time ago. Thanks for that link Victor! And thanks Alan, the #6 spanner was a great hint =)

 

So I received my #6 spanner driver today and adjusted as described. With a 4-second drop time before it went off some 4-5 degrees, and it is now

centered perfectly (the Wagner Horizon I got for it is a nice toy and the 2 degree scale over the whole width of the LED panel helps a lot with getting

this accurate).

 

BUT: I had some initial confusion because I trimmed perfectly 90° to the adjustable axis, just as desribed, but weirdly enough the angle it went out

of center in the adjustable axis wasn't equal - although logic dictates it should. I figured it out anyway, but this way I discovered that in the Axis 90° to

the one that is adjustable - the gimbal is NOT centered  :unsure: It's not badly out of center but still with a 4-second drop time it goes off by 1 degree.

 

Has this happened to anyone else? Is there a way to adjust it in this axis, too, maybe inside the gimbal? (I certainly won't open it to check without

proper instruction...)  If not, could it even mean the gimbal is damaged or is this just normal manufacturing tolerance?

 

Thanks for your input!


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#12 Alan Rencher

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Posted 31 July 2013 - 12:42 PM

Frederic, it's possible that your rig was not balanced perfectly when you were centering the gimbal. Try adjusting the rig's balance while you're over the gimbal's non-adjustable axis using the adjustment screws on the top stage. After you get that perfect, turn the rig 180º then adjust the gimbal.


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#13 Victor Lazaro

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Posted 31 July 2013 - 01:49 PM

Also be careful with the two screw on each side, make sure that the tension is the same after fixing it. If you turn one screw in, turn the other out the same amount.


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#14 Frederic Sturm

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Posted 31 July 2013 - 03:48 PM

Hi Alan, Hi Victor,

Thanks for your quick replies!

Of course I balanced perfectly over the non-adjustable axis first, as the manual states.
And for sure I'm very, very careful to move the screws the same amount not to change the tension.

But whats really weird, is now, a few hours later, it works.
Then I take the rig off the pin, dock it, put it up again, and it doesn't.

But you know what? I think I found the problem just now: letting it settle from one side it has a different
error than when moved over and let settle from the other. I think my drop-time is too low to overcome the
tiny amount of friction that is left in the gimbal, and the error is always below one degree, actually now more
like a 1/3rd degree. So I might have been overly sensitive with this - do you think that makes sense?
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#15 Victor Lazaro

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Posted 31 July 2013 - 05:02 PM

IMHO 1/3 of a degree at a 4 sec drop time might be less than nothing at a standard operating drop time. If you feel it's still an issue, call Tiffen and have your sled sent in for a full checkup.
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