Orpington Astronomical Society

Astronomy => Technical => Topic started by: Fay on Apr 14, 2014, 22:25:16

Title: You know when you feel like giving up....................
Post by: Fay on Apr 14, 2014, 22:25:16
.................testing in garden again, with XP laptop, well dont get a blue screen with that when DMK plugged in via hub.

anyway phd does not calibrate properly with this camera in.
switched to SX and it calibrates as expected, but whereas the guiding graph would be nearly flatlining as in ursa major, it was flatlining until i kept getting a regular "click", from the mount every few seconds, then the RA line would spike, hence messing a good guide graph up all the time.

any clues as to what this click could be?

Thanks
Title: Re: You know when you feel like giving up....................
Post by: Fay on Apr 15, 2014, 21:15:04
have setup tonight for testing. am on mars, no guiding on but the mount is still doing a click, mars jumps up quite a lot every time this happens. which is often..  does anyone know what it could be? could it be seen what is causing it if the side of the mount was taken off?

sounds scary me saying that. i did think it was something to do with guiding yesterday but now know it is the mount
Title: Re: You know when you feel like giving up....................
Post by: mickw on Apr 16, 2014, 01:08:35
You might find the solution in here -

http://forum.orpington-astronomy.org.uk/index.php?topic=7452.msg48161#msg48161 (http://forum.orpington-astronomy.org.uk/index.php?topic=7452.msg48161#msg48161)
Title: Re: You know when you feel like giving up....................
Post by: Fay on Apr 16, 2014, 07:35:51
Mick, it is not coming from the main body, but from inside. i found a possible reference to it on SGL


http://stargazerslounge.com/topic/163915-skywatcher-eq3-2-pro-mount-clicking-noise/
Title: Re: You know when you feel like giving up....................
Post by: MarkS on Apr 16, 2014, 14:33:16
The clicking is a bit of a worry.

I reckon one of the following:
1) Badly meshing gears (but why would it start now)
2) Broken gear tooth (caused by some kind of accident)
3) Some problem with the control board electronics

Which mount is this?

Mark
Title: Re: You know when you feel like giving up....................
Post by: Fay on Apr 16, 2014, 16:49:48
NEQ6 pro. i am thinking of opening it up  : to look at gears when running & clicking. that is all i can do, if they are on show!

if it is the board then not sure what to do. i sent a mail to OVL but they dont answer technical queries, see how that goes.

Title: Re: You know when you feel like giving up....................
Post by: The Thing on Apr 16, 2014, 21:21:29
Sounds like sticking gears making the stepper motor skip. This can happen if your head was banged as the worm block can move a fraction. I take it it doesn't happen when slewing?
Title: Re: You know when you feel like giving up....................
Post by: Carole on Apr 16, 2014, 23:40:31
Fay there's a guy on Astronomy shed who undertakes mount repairs etc if you need to get it repaired.  Not sure where he lives though:

http://www.astronomyshed.co.uk/forum/viewtopic.php?f=102&t=20255

If you're not a member of the shed you might not be able to read the link though.

Carole
Title: Re: You know when you feel like giving up....................
Post by: Fay on Apr 17, 2014, 08:18:41
Thanks Duncan, Carole.

i do not think it is  the gears, as the interval between each click or tic, yes more of a tic,  is too often, not time for a gear to go around.
Title: Re: You know when you feel like giving up....................
Post by: The Thing on Apr 17, 2014, 12:55:54
Quote from: Fay on Apr 17, 2014, 08:18:41
Thanks Duncan, Carole.

i do not think it is  the gears, as the interval between each click or tic, yes more of a tic,  is too often, not time for a gear to go around.
Exactly, the gears are not going round smoothly so the stepper motor is jumping. The motor does 128 (or is it 64) steps per revolution, so if the gears are sticking the motor will do fast tics even if you are simply at tracking speed. Slewing probably overcomes the stiction if it's only ticking when tracking.

BTW I think it is a misconception that the gears/worm ever jump, the motors can't be powerful enough to strip brass and there is no give in the mountings. If gears have stripped it's most likely because of an external mechanical force.
Title: Re: You know when you feel like giving up....................
Post by: Fay on Apr 17, 2014, 13:20:46
had a mail from OVL they say it sounds like a worn out RA motor assembly or a faulty motherboard. i have had the side off but nothing to see, all enclosed. they are not fast ticks just one every few seconds which makes the image jump up or if guiding, the RA on graph spike.  Duncan I am not too conversant with all this, can only learn a bit at a time,

so far i have learned not to stick a screwdriver in if attached to mains
Title: Re: You know when you feel like giving up....................
Post by: Ivor on Apr 17, 2014, 14:25:59
Fay does your noise sound like mine?

http://vimeo.com/92186320 (http://vimeo.com/92186320)

Title: Re: You know when you feel like giving up....................
Post by: Fay on Apr 17, 2014, 16:18:11
No Ivor. yours sounds sort of mechanical but mine sounds electrical
Title: Re: You know when you feel like giving up....................
Post by: MarkS on Apr 18, 2014, 19:35:38
That's a real nuisance Fay.  I really feel for you  :(

Mark
Title: Re: You know when you feel like giving up....................
Post by: Fay on Apr 19, 2014, 08:19:50
all is not lost, Mark. i setup last night, with the purpose of trying to listen with the side off, to find where the "tic" was coming from, and i heard nothing!

it had been very obvious for two nights with different setups, and obvious effects, so will see what happens next time.