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New Mesu appears kaput

MartinB

By MartinB
in Discussions - Mounts

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MartinB

MartinB

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Shouldn't have posted a thread saying how well things were going.  During setting everything up and noticed that occassionally the mount would give a little judder or make a jump in RA.  I had hoped that this was down to problem with balance but this was fine when I checked tonight.  Whilst slewing in both directions of RA to compare the current draw for each direction on several occasions the mount made a rapid small jump and would then stop responding to the hand set in RA.  Dec would continue ok.  Things would be back to normal on switching the controller off and then on again.

I eventually tried connecting to Sky6 with the mount in the park position.  As soon as the connection was made the mount shot off at breakneck speed in RA and was only stopped by switching off the controller.  I disconnected the laptop but whenever I switched the controller on again it would slew in the same direction.  Using the reverse RA direction on the handset would stop it but it would then stop responding in RA but would be ok in dec.  

The video (about to be uploaded) shows the initial problem of a jump in RA leading to a complete stop whilst still responding to the handset in dec.  It then shows some juddering RA motion followed by the uncontrollable slews on switching on the controller.  This is happening everytime the controller is switched on rendering the mount unusable  :mad:

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Zakalwe

Zakalwe

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Have you gone through the troubleshooting section in the manual?

Problem: Every once in a while the scope would just start moving rapidly in one axis without any input from me.
Solution: Most likely an encoder or encoder cable malfunction, where the controller sees the encoder report a far off value, causing the controller to move to the errant reported position. Verify by watching the encoder value display and seeing if indeed the numbers 'go wild'. This is most likely a cable problem (too long, too close to interference) or connector problem (verify that connectors are plugged in snug).

Problem: Motor runs away as soon as power is applied or commanded to move. After running fast for a short time, it stops, and the light flashes.
Solution: The motor encoder relationship to the motor polarity is wrong. See section on “Setting Up the Motors”.

Problem: Upon applying power, one of the motors starts slewing, all by itself. Nothing will stop it.
Solution: Unplug the handpad and see if it still happens. If it stops moving, you've a faulty handpad. If it keeps on moving, it may be there is a problem with the digital input for the handpad.

Problem: On my new SiTech installation on an equatorial mount my mount tracks for a while in RA, then jumps a couple arc-min then jumps back, several times in a 10 minute period.
Solution: This shouldn't happen; it could be that your integral is set too low. One thing to do is click on the "numbers" tab, and watch the PAxisError. It should be near zero all the time. If it suddenly starts moving, then we know that is where the problem is occurring. Another thing to do is call up the "features" tab, then click on "controller stuff". Put your mouse in the Primary Axis OUTPUT window, and watch the controller output. If during the problem this climbs and climbs, then suddenly lowers when the scope returns, then you may want to look for a mechanical problem (like worm or axis bearing binding, or cable hang-ups, etc.). You can also put the

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MartinB

MartinB

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Thanks Zak, I haven't posted in the groups yet, I've been putting a video together showing the problem which should soon appear below.  It still happens with the handpad removed and when completely disconnected from the pc.  If I open sitech.exe, unpark and then switch on the controller it still happens.  I've not looked at the encoder value displays.  

I've treated this mount with kid gloves and followed instructions to the letter.  

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Helen

Helen

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Sorry to hear about the problem Martin   :sad:   very depressing with a new piece of kit.  I had a problem with the sitech a few months ago and Lucas dealt with it very efficiently, so hopefully you can be sorted out quickly too.

Gorgeous day for a bike ride  :grin:  

Helen

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MartinB

MartinB

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The factory config is saved but I also have the config changes I made based on Steve's instructions.  As you know, there are very few changes to make but I did reload the file I created whilst setting up in case I'd inadvertently made some changes whilst faffing around reading the slew currents.  I'll contact Lucas today and send him a link to the video.  I think there is a problem somewhere with Sitech's interpretation of the encoders.

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MartinB

MartinB

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I think it's cured! As part of the investigation Lucas asked me to swap round the Dec and ra connectors to the Sitech controller. Whilst doing this one of the wires popped out. This is now firmly secured and everything seems tickety boo:D

Hopefully I'll get a clear spell tonight for more testing.

Sent from my Nexus 4 using Tapatalk 2

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steppenwolf

steppenwolf

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This is good news, Martin and I hope it is the end of the issue! I am now cursing myself for not suggesting that you check the security of the screw block connectors on the SiTech unit but it seemed too trivial a solution at the time!!

Fingers crossed all is OK now!

Sent from my iPhone from somewhere dark .....

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Zakalwe

Zakalwe

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I think it's cured! As part of the investigation Lucas asked me to swap round the Dec and ra connectors to the Sitech controller. Whilst doing this one of the wires popped out. This is now firmly secured and everything seems tickety boo:D

Hopefully I'll get a clear spell tonight for more testing.

Sent from my Nexus 4 using Tapatalk 2

Great news!

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MartinB

MartinB

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This is good news, Martin and I hope it is the end of the issue! I am now cursing myself for not suggesting that you check the security of the screw block connectors on the SiTech unit but it seemed too trivial a solution at the time!!

Fingers crossed all is OK now!

Sent from my iPhone from somewhere dark .....

Thanks everyone.

Steve, I did a visual inspection of the cables and gave them the gentlest of tugs.  There are 2 black cables into a single connector and I didn't pull on them individually so missed it.  

Last night I took a couple of 30min subs but tracking performance was poor.  The RMS figures were those I'm used too when the seeing isn't too good but stars were far from round.  I've put it down to poor polar alignment and have done another couple of iterations PA.  I then did the automated calpointxp routine, was ok with this once I realised I had to press "play" for it to start!  This ran pretty well except for one occassion when it ignored the horizon setting (and actually reported that the telescope was pointing below the horizon !?), I moved onto the next frame after stopping the plate solve for that frame.  Following a 24 point calibration it is reporting 9mins of PA error in alt and nearly 3 mins in az.  I presume when I restart, hopefully tonight, I can do an offset init and then use this calibration to run another PA adjustment.  I'll try anyway and will then do a drift align.  

The main thing was that the mount have any recurrence of the abnormal movement in RA  :grin:

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Zakalwe

Zakalwe

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Great news.

I am treating those myriad of exposed wires with some suspicion. Exposed contacts on equipment left open to the elements doesn't seem right to me. Perhaps a wee dab of Vaseline or ACF50 might be in order to prevent them turning into a furry, corroded mess?

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