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  #21  
Old 26-06-2009, 11:44 AM
bloodhound31
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Heavy metal gets right up my nose.......
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  #22  
Old 26-06-2009, 11:47 AM
outwestwa
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Hi All
I also had this problem of a tingling sensation from my camera when it was using an external power supply it even extended to the scope and mount, To fix this after speaking to Canon Aust technician the problem was solved by using 2 small alligator clips and some lightweight wire. Attach one of the clips to the camera mount bracket where it mounts to the body and the other to a steel tent peg in the ground and no more tingles.
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  #23  
Old 26-06-2009, 12:13 PM
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Excellent idea. Thanks mate.
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  #24  
Old 26-06-2009, 06:56 PM
TrevorW
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Obviously he had a nose for astronomy !!!
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  #25  
Old 26-06-2009, 07:51 PM
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astroron (Ron)
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Quote:
Originally Posted by jjjnettie View Post
Imagine the mess when he got a cold? Yuk!
Jeanette trust you to think of that
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  #26  
Old 29-06-2009, 06:47 AM
Dennis
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I was working on my observing hutch this morning which serves as a power distribution point for all my astronomy gear in the field. I have 2 off x6 socket power boards and an industrial strength Residual Current Detector (RCD) Circuit Breaker fitted.

Those people who are getting tingles, do you have an RCD fitted?

If the answer is a unanimous no, then maybe this is why I’m not getting these tingles on my 40D?

Cheers

Dennis
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  #27  
Old 29-06-2009, 07:14 AM
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An update from another forum I posted this in:

"DDCSD,

Should not make any difference if everything is working correctly. Here in the UK we use a PME system. Effectively all the metalwork in a building is kept at the same potential so anyone standing in it is at that same potential, even if there are hundreds of volts shorting to earth.

And if the camera transformer pack is working correctly to remove any earth return path in the secondary windings, then "in theory" its impossible to get a shock. However, theres theory and theres practise. And the two can be miles apart!

Edited to add: Troy, I think I have grasped the point. You are outside the house? In the Garden? In that situation you should use an Earth leakage circuit breaker because you are effectively outside the protective "CAGE" I have tried to explain above. Read up on recommended protection for AC Lawn Mowers and the like. Current Operated earth leakage circuit breakers can be bought that simply plug into a 13amp socket and allow the equipment to plug into that. Go and see your local Electrical Wholesaler, trust me they will have what you need. The telescope is sitting on a randomly fluctuating voltage and thats the problem, not the camera kit. That's my guess at least. Personally I'd stick with batteries outside the protected house environment.
"
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  #28  
Old 29-06-2009, 07:27 AM
Dennis
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Hmm, although our house is an older property, the previous owner was an electrician by trade and he wired in some external lights and an external power point. I wonder if he installed any fancy earthing for that external power point which feeds my observing hutch?

On a similar note, I once had a circulating current in my system that made the auto guider cable heat up. This was traced to a faulty mains adapter where a big metal heat sink had rotated inside the unit and was actually shorting to the metal case. As soon as this was repositioned correctly, the circulating current stopped.

This electrickery can be quite scary stuff!

Cheers

Dennis
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  #29  
Old 15-07-2009, 07:29 AM
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Just thought I'd followup here. I had an opportunity the other night to do some more astro-imaging with my 30D and the AC adapter, but this time I used a 12V battery instead of the house mains. There was no tingling/shock this time. So it seems to be only when powered from mains 240V supply.
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  #30  
Old 07-08-2009, 12:28 PM
Bob Jones
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I recently felt a tingle in my eyelashes from the Polarscope on my EQ6 pro mount. Because my 2 Mallincams also "tingle" I decided to test them with a Multimeter.

The Mallincams leak 0.07 - 0.13 volts but this increases to 0.17 - 0.21 volts when their heater/ coolers are switched on. The EQ6 pro leaks 0.06-0.07 volts but rises to 0.21-0.23 volts when the motors are at full speed.

I will test some other mounts at Astrofest. Don from Bintel and Rob at Skywatcher could not explain

Bob J
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  #31  
Old 10-08-2009, 11:58 PM
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g__day (Matthew)
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Mine did that to me twice - I told Canon Head Office and they totally freaked! They checked and I think replaced the adapter. If its tingling surely that means its over 50V to be felt on dry human skin. And if the adapter is pushing that much potential at times - I'd worry its pushing out a dangerous ampage too.

Call Canon and see if you can get it checked.
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  #32  
Old 11-08-2009, 05:34 PM
Karls48 (Karl)
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Tingling and slight shocks given by Astro equipment is caused in most of cases by Switch mode power supplies. Almost all of these are “double insulated” having no DC path to the earth and most have 0Volts output (what is generally described as “negative”) connected to the chassis of camera or telescope mount. All of them produce common mode noise that can be measured as voltage ranging from few volts to tens of volts common to both outputs. What it means is that if you measure AC voltage across the output terminals you will read few millivolts. But if you measure Voltage from either output to good earth you may measure anything from couple of Volts to 90 V. This is the reason for tingle you are getting. Your body is providing DC path from the metal chassis of your camera or telescope to the earth. All the measurements I’m referring to are done with digital multimeter with input impedance of 10Mega Ohms. If you try to do same measurement with old analogue meter that had input impedance from 10 to 100 K, the needle will hardly move. The current that passes thru your body during the tingle is less then 1nA.
When you connect two or three PS to power different pieces of your Astor gear that is in electrical contact with each other situation gets even more complicated.
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