Goto and Slew problems EQ5

[cuivenion]

I have an EQ5 controlled via AstroEQ. I've noticed that when slewing east when I stop the slew it just keeps going, unless I tap west a few times and then the mount stops. Also occasionally when slewing north I'll have to hold down the button for quite a few seconds before the mount starts to move. I can hear the stepper motor but the mount doesn't seem to move.

These problems have been steadily getting worse over a few sessions and is effecting the accuracy of my gotos. Is this likely a simple case of backlash and/or belt tension that can be adjusted or something more serious. Any advice you have would be great.

[John78]

The motor moving north but scope not moving sounds like the clutch is slipping - either try tightening it up more (if its at the end stop already unscrew the lever and move it round a bit!), if it is slipping due to poor balance you can try to adjust that a bit better - if that is the root cause then it will slip one direction but run fine the other...

I cant answer why it keeps slewing when you let go of the button though - is the PC fast enough?  Like its lag between you letting go of the button and the scope coming to rest or would it just run forever if unchecked?

[cuivenion]

On the first point, thanks I'll check that out. On the the second I'm afraid I'm not sure as I've always stopped it, I'll have to check. Just to confirm east/west is RA and north/south is DEC isn't it?

Thanks for your help.

[ronin]

May  be a bit odd to ask and I have not kept track of things but is the mount converted to a belt drive by yourself or anyone else. Or is it just the term that you used ?

If it has a belt conversion then which one?

[alacant]

Hi

Try changing the key repeat rate -the rate at which the key repeats if held down- to a lower rate. I think it will try to flush the buffer even if you let go and that's why you may see overrun. The rate at which the pulses are sent are faster than the mount can respond:

http://windows.microsoft.com/en-us/windows/change-keyboard-settings#1TC=windows-7

[cuivenion]

9 minutes ago, ronin said:

May  be a bit odd to ask and I have not kept track of things but is the mount converted to a belt drive by yourself or anyone else. Or is it just the term that you used ?

If it has a belt conversion then which one?

I fitted mine according to instructions on the AstroEQ site. This isn't mine but it's similer.

[cuivenion]

3 minutes ago, alacant said:

Hi

Try changing the key repeat rate -the rate at which the key repeats if held down- to a lower rate. I think it will try to flush the buffer even if you let go and that's why you may see overrun. The rate at which the pulses are sent are faster than the mount can respond:

http://windows.microsoft.com/en-us/windows/change-keyboard-settings#1TC=windows-7

Thanks I'll give it a look. I don't think it's the problem though as it only happens in one direction.

[cuivenion]

Just had a thought, the RA worm does move up and down slightly when it's turning. Could that have anything to do with it?

[ronin]

I asked as I was unaware of a belt mod for the EQ5 that maintained the correct ratio's for the gears. I was aware of at least one belt drive mod but the problem was that the gear ratio's were lost and so driving the mount was then in error. I have an EQ5 and when belt drive mods were talked of I looked at the option as part of an upgrade to it. Will say it was about 2 or 3 years back I looked at into it.

My thought as you will have guessed being is the problem the belt drive no longer operating with the correct gear ratio's.

[cuivenion]

7 minutes ago, ronin said:

I asked as I was unaware of a belt mod for the EQ5 that maintained the correct ratio's for the gears. I was aware of at least one belt drive mod but the problem was that the gear ratio's were lost and so driving the mount was then in error. I have an EQ5 and when belt drive mods were talked of I looked at the option as part of an upgrade to it. Will say it was about 2 or 3 years back I looked at into it.

My thought as you will have guessed being is the problem the belt drive no longer operating with the correct gear ratio's.

Not sure I follow, how would the gear ratio's be lost? I haven't changed the gear ratio's in the software. If the gear ratios were wrong I imagine the gotos would be wildly inaccurate, they're not that bad they could just be a lot better. For example I had a lot of trouble in my last session using Alignmaster to polaralign.

[ronin]

Afraid I cannot really help much more it was simply something I recall looking up and reading about. The drive ratios are, or were, lost as the replacement gears are somewhat oddly different to the original - don't ask why as I have no idea, it seems utterly pointless.

There is this beltingonline site that has an EQ5 belt conversion and they say that the kit is not suitable for use with the handset, only with EQmod. As I think Rowan Astronomy do not make an EQ5 kit I presume that my memory came from the beltingonline kit (or another similar).

http://www.beltingonline.com/eq5-telescope-belt-mod-drive-kit-12097

Really all I was commenting on was if you have an EQ5 with a belt modification is the actual belt modification fully compatible.

Every chance that since I looked someone has produced a fully compatible kit, it would make sense. It was no more then a verification that what you have is fully correct/compatible with the remainder of the system. Caused as said that when I looked, a couple of years back, a 100% EQ5 belt mod was not fully available. It was your mention of belt tension and EQ5 that triggered the memory, as in "Someone has made one at last have they, better ask to make sure."

 

[cuivenion]

Thanks for reply ronin. It's the same gearing/belts the inventor of AstroEQ uses on his eq5, so hopefully it should be OK.

[cuivenion]

It turns out that the North/South problem was extremely bad backlash. I had to tap new M6 holes for the adjustment bolts as one of them had threaded. For the other problems TWO of the timing pulleys set screws had become loose, so no wonder everything was miles out. I've since tested and everything seems to be a lot better, gotos are landing near the center of the crosshairs. There is still very slight backlash in the dec, but it doesnt seem to be effecting gotos so I'll probably come back to that.

The overrunning in the east is something I couldn't recreate, I had a theory that it could be the motor connecter pins being exposed to due and being close together, so I've covered them in silicone sealant. Touchwood no problems so for.