EQ3 Synscan Pro Problem

[Thalestris24]

Hi

I've been having a problem with my eq3 pro recently. After running for a while it will suddenly start drifting in RA - messing up my images! This is unguided, btw. I'm wondering if any other EQ3 Pro owners have experienced the same problem? I can't see any obvious reasons - power supply is good. I ran it from the mains last night and still had the problem after several hours. It also has a problem whereby it doesn't settle down for several minutes after slewing but that's likely a separate issue and I can live with that. I only have a 200mm lens and qhy5l-ii on it. I was experiencing the same problem when I had my 80mm APO on it (which is why I moved it to my heq5  ). Maybe it sticks in RA for some reason but it only happens after several hours. Any ideas? I'm running a daytime test on it at the mo. So far, so good - of course!

Thanks in advance

Louise

[symmetal]

I imagine it's sticking a bit in RA, maybe needing a re-greasing. To check switch your multimeter to amps (assuming you have one ) and measure the current taken from the power supply while you drive the mount around in RA at a low speed. A sticking point should show up as an increase in current taken. At night as everything cools the grease will be thicker so would show problems more than when everything is warm indoors. Also thermal contraction at night could make sticky points more noticeable.

Alan

[Thalestris24]

2 minutes ago, symmetal said:

I imagine it's sticking a bit in RA, maybe needing a re-greasing. To check switch your multimeter to amps (assuming you have one ) and measure the current taken from the power supply while you drive the mount around in RA at a low speed. A sticking point should show up as an increase in current taken. At night as everything cools the grease will be thicker so would show problems more than when everything is warm indoors. Also thermal contraction at night could make sticky points more noticeable.

Alan

Thanks. Yeah, I thought it might be temperature related though I do all my imaging from indoors. It's not that it has a 'sticky bit', since once it starts misbehaving, it continues. I'll take the cover off the RA motor and have a peak.

Louise

[wimvb]

When this happens, have you tried power cycling it (turn off, turn on)? This will mess up the goto of course. I haven't used my eq3 for ages, but your problem seems familiar. Also, when the drift happens, try pushing one of the ra buttons on the hand controller. This may stop it. I wonder if this is a mechanical or an electrical issue.

[Thalestris24]

24 minutes ago, wimvb said:

When this happens, have you tried power cycling it (turn off, turn on)? This will mess up the goto of course. I haven't used my eq3 for ages, but your problem seems familiar. Also, when the drift happens, try pushing one of the ra buttons on the hand controller. This may stop it. I wonder if this is a mechanical or an electrical issue.

Hi Wim

I only use it via eqmod - have never used the hand controller! I just took off the RA motor, gave the cogs a clean and regreased them. Will see if that helps. It could, of course be to do with the RA axis rather than the motors. Or the worm - which seems to have a lot of play in it. I'm not sure how to adjust the RA worm, though, and I don't want to make things worse! I noticed both the RA motor cover and the motor itself were both quite warm though that might be normal. I'll see how it behaves after the regreasing. Cloud and rain tonight so won't be able to test yet

Louise

[wimvb]

In case you need to adjust the gear:

Adjusting the worm gear is rather easy on the EQ3. There is a block with 2+1 push/pull hex bolts where the motors and slo-mo knobs are attached. If you turn power to the motors off, it's possible to rotate the worm with the slo-mo knobs, and it's easy to see if you have backlash. There's an old thread here (you don't need to strip down the mount to adjust the gear):

Probably the DEC gear will have some play (backlash), and it's less critical for tracking. So you can "practice" on that gear to get a feel for how the mechanism works.

The motors can get warm, but probably shouldn't become hot. I found tracking and guiding much improved when I didn't tighten the clutches so much. When powered the motors should have enough holding torque to keep the mount from moving/slipping, even with the clutches released.

Hope this helps

[Thalestris24]

7 minutes ago, wimvb said:

In case you need to adjust the gear:

Adjusting the worm gear is rather easy on the EQ3. There is a block with 2+1 push/pull hex bolts where the motors and slo-mo knobs are attached. If you turn power to the motors off, it's possible to rotate the worm with the slo-mo knobs, and it's easy to see if you have backlash. There's an old thread here (you don't need to strip down the mount to adjust the gear):

Probably the DEC gear will have some play (backlash), and it's less critical for tracking. So you can "practice" on that gear to get a feel for how the mechanism works.

The motors can get warm, but probably shouldn't become hot. I found tracking and guiding much improved when I didn't tighten the clutches so much. When powered the motors should have enough holding torque to keep the mount from moving/slipping, even with the clutches released.

Hope this helps

Thanks, Wim

I've done the DEC before but not the RA. If the problem continues I might do the strip-down

Louise

[wimvb]

The trickiest part with the strip down is the aluminium threaded ring that holds the RA shaft in place. I had missed the three small grub screws that lock this ring, and almost stripped the thread (RA Axis step 3 in the linked post in my previous reply). Another thing to note is that the EQ3 has no ball bearings in the RA and Dec axes. It's the grease that provides more or less "smooth running". It's a budget mount after all.

Good luck if you decide for major surgery. ?

[Thalestris24]

24 minutes ago, wimvb said:

The trickiest part with the strip down is the aluminium threaded ring that holds the RA shaft in place. I had missed the three small grub screws that lock this ring, and almost stripped the thread (RA Axis step 3 in the linked post in my previous reply). Another thing to note is that the EQ3 has no ball bearings in the RA and Dec axes. It's the grease that provides more or less "smooth running". It's a budget mount after all.

Good luck if you decide for major surgery. ?

I've stripped my heq5 before . I'm actually testing the eq3 just now - unforecast clear spell (only likely to last a short time). Still, so far, so good. Will keep an eye on it.

Louise

[Alien 13]

Hi Louise, have you removed the screw just above the setting circles?, the mechanism can cause a lot of intermittent drag...

Alan

[Thalestris24]

1 hour ago, Alien 13 said:

Hi Louise, have you removed the screw just above the setting circles?, the mechanism can cause a lot of intermittent drag...

Alan

Hi Alan

How's you? The setting circle screw is very loose but thanks for the suggestion

Louise

[Alien 13]

17 minutes ago, Thalestris24 said:

Hi Alan

How's you? The setting circle screw is very loose but thanks for the suggestion

Louise

If the both parts of the setting circle spins with the RA axis then its loose enough...

Alan

[Thalestris24]

2 minutes ago, Alien 13 said:

If the both parts of the setting circle spins with the RA axis then its loose enough...

Alan

Yeah, it's very loose

[Thalestris24]

Back trying the RA stripdown again! It looks like I must have previously removed the 3 grub screws (can't see any screws in any of the holes). But can't undo the threaded end ring/plate with the two holes  Is it supposed to come undone easily? I'm sure my heq5 one came undone easily. Would one of these help: https://www.amazon.co.uk/Neewer®-Professional-Stainless-Spanner-Opening/dp/B00J5F6ZI2/ref=sr_1_7?keywords=camera+wrench&qid=1559149723&s=gateway&sr=8-7

Any suggestions/advice?

Cheers

Louise

[Dr_Ju_ju]

Yes, it should come apart easily.... 

Even though you say that there are no grub screws visible, they mat still be there, but well buried.....  even they should only be done up with minimal force.

Gently try an M2.5\M3 Allen key to see if they are still there....

you could buy one of the Amazon spanner wrenches, but personally, I make my own by simply using appropriate sized nails, hammered into a piece of wood (at the correct spacing.....

 

 

[Thalestris24]

4 minutes ago, Dr_Ju_ju said:

Yes, it should come apart easily.... 

Even though you say that there are no grub screws visible, they mat still be there, but well buried.....  even they should only be done up with minimal force.

Gently try an M2.5\M3 Allen key to see if they are still there....

you could buy one of the Amazon spanner wrenches, but personally, I make my own by simply using appropriate sized nails, hammered into a piece of wood (at the correct spacing.....

 

 

Oh thanks, Julian. I just reposted in a new thread! Took a pic of what I can see. I can't get any allen key to do anything which convinces me the screws are out. I've tried with nails in wood without much success. I'm very limited as to what I can knock up. Is the correct size 2.5mm??

[Dr_Ju_ju]

Unfortunately, my mount is currently buried under the stair as I'm rebuilding my kitchen and there's stuff every where, so unable to check, but your picture suspiciously looks like there's a grub screw still there.

If you think its clear, and you have some spare M2.5\M3 (I can't remember which size) bolts then try gently screwing one in. If it goes in and holds, then the holes are clear, if not, the grub screws are still there....

[Thalestris24]

9 minutes ago, Dr_Ju_ju said:

Unfortunately, my mount is currently buried under the stair as I'm rebuilding my kitchen and there's stuff every where, so unable to check, but your picture suspiciously looks like there's a grub screw still there.

If you think its clear, and you have some spare M2.5\M3 (I can't remember which size) bolts then try gently screwing one in. If it goes in and holds, then the holes are clear, if not, the grub screws are still there....

Anything I can get in the hole just goes round and round... :-| It's looking like I'll have to abandon it

 

[Dr_Ju_ju]

Yes its possible 'round-off' grub screws....  But all may not be lost, 2 things to try, depending how brave\well equipped you are:

1, drill out the grub screw, then re-tap when removed or

2. if you have good quality Allen keys then insert one the next size up e.g. if its M3 then use M3.5, but you also need to gently hammer in the key so that it binds with the screw..... 

In both instances, throw away the old grub screws, in favour of new ones.

 

[Thalestris24]

1 hour ago, Dr_Ju_ju said:

Yes its possible 'round-off' grub screws....  But all may not be lost, 2 things to try, depending how brave\well equipped you are:

1, drill out the grub screw, then re-tap when removed or

2. if you have good quality Allen keys then insert one the next size up e.g. if its M3 then use M3.5, but you also need to gently hammer in the key so that it binds with the screw..... 

In both instances, throw away the old grub screws, in favour of new ones.

 

It's ok, the grub screws were there after all, tut! It turned out that I needed a much smaller key - about 1.4-1.5mm.  So finally got them out - yay! I've now been able to move the end disc but can't actually unscrew it. I can turn it clockwise a bit and anti-clockwise a bit but at least some progress. I wonder why it's getting stuck - can't see any obvious reason. Am I missing something??

Louise

[Dr_Ju_ju]

You put the grub screws in so hard, that the main thread is binding, If you have any spray a little WD40 into the grub screw holes & lets it work its way onto the thread. Hopefully it will ease things up....

[Thalestris24]

8 minutes ago, Dr_Ju_ju said:

You put the grub screws in so hard, that the main thread is binding, If you have any spray a little WD40 into the grub screw holes & lets it work its way onto the thread. Hopefully it will ease things up....

Me? I didn't put them in or tighten them - I've been battling to get them out! Having taken the disc out after some difficulty all the way, there are burrs - which I imagine was causing the binding. I will clean everything up and hopefully end up with a smother RA axis. I did the DEC axis yesterday and there were burrs/chaff in there too. Must be sloppy q.c. Anyway, at least I can make some more progress now. Hopefully, it will end up better - fingers crossed!

Thanks

Louise

[Dr_Ju_ju]

SW, are renowned for poor QC, I've found swarf in all my mounts when stripped down....

 also make sure that every part you remove you note on a 'chart' detailing its location and orientation, to make it easier to put it all back together, and take photos

[Thalestris24]

4 minutes ago, Dr_Ju_ju said:

SW, are renowned for poor QC, I've found swarf in all my mounts when stripped down....

 also make sure that every part you remove you note on a 'chart' detailing its location and orientation, to make it easier to put it all back together, and take photos

Does seem like it! I'm doing sections at a time and with the support of the old SGL guide and YouTube video. There's nothing complex about the EQ3 Pro...  

Louise