HEQ5 Pro Backflash problems

[Xavier Bertrand]

Dear All,

last weeks, I'd started to have bad performence on pHD2 with my HEQ5 PRo Goto.

SO After search, I tryied to setup the backflash.

In the first use after the setup, I'd big noise and problems during movement, It seems that I had little bit torques too much...

I solved this and yesterday, everything was going well but the DEC axis has very poor performence.

When I try to understand the curve of correction, I think that the problem is the backflash in DEC axis... but I havent Backflash anymore now.

My opinion is that when I had problems some teeth of gear were damage...

But As it's only 1 year of practicing AStrophotography... I'm not sure.

Can you help me?

If it's the gear damage... do you have some tutorial to change them?

THanks  a lot

[Bruce Waddington]

There's very little information to work with here.  We don't know what your guiding arrangement looks like for example.  What you need to remember is that the Dec axis is normally idle during guiding so it's pretty difficult for gear-related problems to trigger these big spikes.  These are more likely coming from something else - something loose in the guiding assembly, dragging or snagging cables, a loose clutch, wind gusts, etc.  Having said that, if you've tightened the Dec axis while trying to reduce backlash, there's some likelihood that you've over-tightened it and now have binding and stiction on the axis.  From looking at just the one 20 min guiding session, I would say that's a definite possibility.  Some backlash is expected and can be handled pretty well by guiding, but binding and stiction are more serious problems.  You might want to check with a different forum, one that is more oriented to the mechanics of your particular mount.

Good luck,

Bruce

[Xavier Bertrand]

Thnks for your answer.

SO I use camera ASI224MC with guide 240/60

You'll find an export of this evening with lot of test, calibration and so one...

I think, I have to unmount everything on my HEQ5 Pro and check everything if nobody can help me.

https://openphdguiding.org/logs/dl/PHD2_logs_HekM.zip

[Bruce Waddington]

There are probably multiple things wrong with your setup, but the place to start looking is the mounting of the guiding assembly and the cable routing.  Look at the Dec behavior when there was no guiding and the Dec motor was completely idle (Dec in green):

Something is moving around or the cables are creating a big problem.  Of course, the measurement scale is still tiny.  This 60 arc-sec unwanted movement is equivalent to a shift of the guide camera sensor by about 18 pixels, which at your image scale is about 70 microns - something a bit larger than the thickness of a human hair.

Hope you can track it down,

Bruce

[Xavier Bertrand]

I was making a measurement of the DEC backlash so the output was disabled...

I let everything guiding for this night and will post the export tomorow morning.

I'm sure no cables are invovled everything is in place and fixed.

I've never had this kind of problems before.

[Brian Valente]

xavier

cables are only one example of what could be causing this. If you examine the cable routing and are confident that is it secure, then you need to consider mechanical problems in your mount. That is something you should consider, especially since you have been working on adjusting the gear meshing and mechanics

Brian

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Brian Valente

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[Xavier Bertrand]

Brian,

I agree with you for the mechanical problem..

I think I will unmount my DEC axis... check, clean everything... My opinion was that the worm drive or worm gear were damaged...

ANd the only things that I can do is to unmount it and check.

I was hoping that the problem was not this one...

FInally, I stopped everything, to much wind too... so you'll find the last log files...

But seems that the next step is to check worm drives and worm gears.

https://openphdguiding.org/logs/dl/PHD2_logs_Ver8.zip

Thanks a lot