EQ8: Dec binding or total failure?

[Zakalwe]

One thing that has alays struck me about this hobby is how much of a "feel" you need for many aspects. The AP link is an example: "Re-tighten with a moderate amount of torque.", "The tighter the screw, the harder you have to tap with the hammer. The looser the screw, the gentler you have to tap." Stuff like that makes my inner engineer cringe. What happened to proper torque settings, for example???

[ollypenrice]

What happened to proper torque settings, for example???

They've been 'leveraged out' by quicker methods, mate. 

Olly

[Zakalwe]

They've been 'leveraged out' by quicker methods, mate. 

Olly

A calibrated elbow?

Man. oh man, have I ever learned my lesson countless times about ignoring toque setting when messing with cars and bikes. "I'll just give that another little nip up". PING. Fall to knees and howl at the sky in impotent rage. :mad:

[Alien 13]

Ive got this picture in my head now of a guy in the skywatcher factory at the end of the assembly line with a big hammer but seiously any product sold should be fit for purpose straight out of the box at the cheaper end of the market you could also expect a few minor tweeks/adjustments to bring out consistant performance but thats all.

The thought of deep rooted design/quality issues is so so wrong, i feel for you guys.

[Photosbykev]

an experienced craftsman with a hammer can achieve some amazing results but in the hands of an amateur a hammer is like a stick of dynamite !

[narrowbandpaul]

Hi Olly,

I wasn't implying you were having a rant, merely agreeing that this situation shouldn't have happened. You certainly weren't stereotyping anyone. I think eq8 owners whose mounts are playing up have the right to feel let down. I hope synta fix the issue because they could be on to a winner.

Paul

[Bubbles82]

The two biggest points that disappoint me with this is when skywatcher released there eq6 gt they seem to have done a fantastic job of it and had learnt from previous faults ( bendy bolts) for example and continued to refine these sort of things.The eq8 wasn't exactly rushed to market rumours had been around for a long time and a few prototype models were kicking around for a long while before release , they hadn't released any price teasers so could have spent the extra money on a few last minute changes and we would of been none the wiser . I'm not bashing skywatcher over this mount because it's a lot of mount for the money compared to the competition and will no doubt be another product that allows us without endless funds to get some fantastic results. Nearly all my scopes are skywatcher and I'm extremely happy with them,and am watching and waiting to buy a new esprit 80 and eq8 in the new year but want to see and here more user reviews first.

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[ollypenrice]

Hi Olly,

I wasn't implying you were having a rant, merely agreeing that this situation shouldn't have happened. You certainly weren't stereotyping anyone. I think eq8 owners whose mounts are playing up have the right to feel let down. I hope synta fix the issue because they could be on to a winner.

Paul

I know Paul, no worries.

Olly

[wxsatuser]

Ive got this picture in my head now of a guy in the skywatcher factory at the end of the assembly line with a big hammer but seiously any product sold should be fit for purpose straight out of the box at the cheaper end of the market you could also expect a few minor tweeks/adjustments to bring out consistant performance but thats all.

The thought of deep rooted design/quality issues is so so wrong, i feel for you guys.

I work in the electric motor industry.

Every new motor is taken out of the box and tweaked so the customer hopefully does'nt have to.

If we did'nt the returns would be horrendous.

[SnakeyJ]

Most interesting and informed thread - which I've just picked up and read through.    Perhaps no big surprises with a new product that is so different and such a big step up from it's predecessors.    As always its the simplest things that tarnish reputation and as my Granddad (RN engineer) would have said 'don't spoil the ship for a ha'p'orth of tar'!

To those already invested and experiencing problems, I hope some reverse pressure through the system will persuade Synta to face up and arrange a repair/fix - this certainly is not a cheap consumable item.   Given the reach of the internet and forums such as SGL, and the undoubted publicity that this will attract from their competitors, they would be ill advised to bury heads in sand.

At the very worst case, I would have thought there was an excellent niche market for an astro engineering firm to produce replacement worm and gear wheels.

Zakalwe's posts raised a smile - in the army a 2lb ball pein hammer was affectionately known as the 'precision adjusting tool' - though I'm not sure this applied when wielded by the REME VM's.   Though I did meet some very skilled VMs who could heft the 'precision adjusting tool' a good 12 yds to knock a can of Cheese Possessed (bails) of the top of an entrenching tool (stumps) in a game of Nurdles.    This became quite a dangerous sport after a few tins were consumed

[NickK]

My only add is - let's not forget that the customer is right - and that customer is paying a large amount of money for something that "should just work". That goes for all products.

[ollypenrice]

My only add is - let's not forget that the customer is right - and that customer is paying a large amount of money for something that "should just work". That goes for all products.

I absolutely agree with this, Nick. When you put a product on the market at Price X you are saying, We can make and sell this in working order for Price X. You are not saying, This is very cheap for what it is and we can't really make it for Price X but you might be able to get it sorted with a bit of fiddling or put up with parts of it that don't work.

I make this as a general point, not specific to the EQ8 of which there seem to be lots of satisfactory examples as well as some more questionable ones.

Olly

[Peter Drew]

Something must have gone wrong during the machining of at least a batch of these gear wheels, there is no excuse for eccentricity, making the gear blank concentric is the simplest part of the whole process, and one of the most important. You cant remove the effect of eccentricity by adjusting the worm, the wormwheel would have to be replaced. This is not a design issue, just one of QC. 

[pete_l]

but seiously any product sold should be fit for purpose straight out of the box at the cheaper end of the market you could also expect a few minor tweeks/adjustments to bring out consistant performance but thats all.

Hang on a sec. How many fixes, fettles, add-ons and workarounds are there for astronomical gear? The answer is that they are very common. Whether it is having to collimate your brand new reflector, adding a field flattener for photographic use or tweaking a mount; from biasing the balance in a given direction though to replacing its gearing with a belt drive.

We all know that astronomy gear always needs adjustments and that none of it's perfect (we know a mount will exhibit periodic error - we accept that imperfection) - be it fresh out of the box or bought second-hand off ebay.

The EQ8 isn't the first mount to have teething troubles. There are many, many cases of mounts at all price points from lots of different manufacturers and countries having problems: some even leading to a general recall.  Just take a look back in the internet archives and you'll find that even mounts like the Paramount ME had some troubles when it was first released. In fact, it could even be that this is the rule - not the exception.

We seem to forget that astro gear is made in very small numbers, compared with consumer electronics, white goods or cars. As a consequence pretty much every significant piece of gear is, effectively, a beta-test product for the first year or two - sometimes forever.

So while I'm sure it's annoying for the people who have discovered a fault with their EQ8's, we still have no information about whether those faults affect the majority of users, or just a tiny but vocal percentage. However it does seem that the adverse publicity is having the desired effect of making people think twice about buying - which will put pressure on the manufacturers to improve the product. Hopefully, they will respond quickly.

Whether that fix can be backed into the mounts that people have already purchased, or not - it's just a reminder about the hazards of new products when compared with tried and trusted models.

We saw binding problems with the early model iEQ45s just a few years ago. It seems the same lesson is being re-learned now.

[sloz1664]

Consumer law is vague at the best of times.

But, all products must be fit for the purpose they were purchased to do.

The EQ8 is, by all accounts, not fit for purpose. The downside

is SW accepting responsibility. This is where forums come into their own,

you have a voice. If it was me I would gather the information via the EQ8 Group Forum and

go from there.

cheers

Steve

[astronymonkey]

I know many bits of astro kit get tweaked to make them work better but this is a basic error on one of the most imprtant parts of the mount ..... making sure the hole is drilled in the middle of the gears to make sure they run in a true circle. Im no engineer but as has been said this is possible on even the most basic lathes so there can be not excuse for getting this wrong.

even if errors are made then quality control on the recieved parts should pick this up, as should the fitter who is putting the worm and drive gear together, especially since the company have said an adjustment is made when it is being assembled so im suprised these have slipped through .

cheers

[George]

I raised an eyebrow when the 1st betas of the EQ8 were released, my first thoughts were why worm and wheel again when direct drive is much simpler and not so reliant on engineering tolerances. A few thou out in most consumer goods would probably go un-noticed, not so a telescope mount, precision is the top goal with a mount and sadly I don't think the Chinese can mass produce precision products.

[Zakalwe]

Direct drive is very tricky though, isn't it? Designing a motor to do 1 revolution per day isn't easy. ASA, for example, have reportedly have had lots of problems with theirs.

[Stu_2011]

Hi,

I'm interested in this thread as I have an Esprit 80 that is far from perfect and I'm hoping to get it sorted in the new year. I have so far refrained from airing my views in public as I'm certain that the supplier will sort things.

These forums are funny places at times aren't they, you could quite easy read a few reviews on the EQ8 and come to the conclusion that all these new EQ8 mounts are faulty and that Skywatcher are not helping anyone. It's obvious that some EQ8 mounts have problems but has Skywatcher actually said that they are not going to fix the faulty mounts? Have any of the local suppliers refused to help sort these problems?

I started reading about the highly regarded Mesu mounts a while ago and one of the first threads I came across talked about a batch of faulty encoders being fitted to the mounts and the owner of the company driving all round the UK and Europe and personally changing encoders. It's not just Skywatcher that gets things wrong in the early days is it?

Maybe its bad timing with the Xmas holidays and therefore email replies are a bit slow on these things.

Let's hope the EQ8 gets sorted, it promises to be a great mount and it's on my list for the future.

Thanks

Sent from my iPad using Tapatalk

[pete_l]

Direct drive is very tricky though, isn't it? Designing a motor to do 1 revolution per day isn't easy. ASA, for example, have reportedly have had lots of problems with theirs.

Heh, heh. As ASA found out, it's not as simple as that.

When they *did* get their DD mount operating, it turned out that it was a little too perfect.   While the mount would track the stars precisely, the mechanicals in users telescopes weren't quite as stiff as the mounts were. So they had to get the controlling software to do a dry-run over the course of where the target object would move during the imaging session, and then take some sample images to model the atmospheric refraction, flex and "floppiness" of the scope's mirror to account for its imperfections.

Of course you don't have these issues with an OAG, as the tracking sensor "sees" the sky after it's been through the telescope, so that compensates for all the scope's mirror flop and and other forms of sag, by default.

[ollypenrice]

A direct drive is about the hardest of all systems to get right. One ASA owner I know, who loves the mount, does say quite seriously that if you're not an electrical engineer then don't buy one because your chances of getting it to perform will be slim. I wouldn't buy one because, of the five owners I know personally, every one of them has had a struggle with it and they are all more technically minded than I am.

It was not the first batch of Mesus that had the problems but the second, the siTech versions which are suitable for robotic control. The point is valid, though.

My own point is simple. SW have explained that their technicians set the worms to the optimal mesh at the tightest point on the wheel, leaving backlash on the slackest part. Someone actually did that on the mount I received and decided it was OK. It isn't OK. It shouldn't have been sent out. That's the beginning and end of my point, really.

Olly

[Davey-T]

Same old same old, either be prepared to spend over £5000.00, [at least] or be prepared to take it apart and rebuild it.

The usual modern approach ( possibly started by Microsoft ) is to let the customer do the QC testing.

Dave

[George]

Direct drive is very tricky though, isn't it? Designing a motor to do 1 revolution per day isn't easy. ASA, for example, have reportedly have had lots of problems with theirs.

The Chinese would just backward engineer one that did work, my point tho was the EQ6 was always compromised by the worm and wheel and engineering wise (on a budget) is next to impossible todo away without some slop in gearing. This slop introduces PE which of course if its repeatable can be compensated with software.

But on another note, UK astronomers have to contend with very turbulent seeing at the best of times and will in due course never get the best out of a mount for that reason.

[Spookylight]

Ok guys, here's what I got back from a Synta engineer re the EQ8 Dec seizure problem.

"Before you unbolt the Dec. assembly, would you please try to increase the backlash at the position where the axis got jammed?

On a conversation with our engineer on what is the proper backlash on an EQ8 mount, I was told these:

1. There is unavoidable machining error which lead to tiny centering offset of the axis of the worm wheel.

2. During the assembly process in the factory, our technician will find the maximum “high” point on the worm wheel and adjust the worm block to allow a small spacing for the worm-wheel meshing.

3. The result is that the backlash at the “low” point of the worm might be higher.

A spring loaded worm might be the way to solve the problem, but it was not implemented on the EQ8 mount.

My suggestions are,

1. Do not seek for zero backlash on the EQ8 mount when users try to tune the backlash by themselves.

2. Slightly unbalance the Dec and RA.

If you extended the backlash and find the problem is still there, please let me know. I will try to find out to what level that we can release the technical document..."

If what they are saying is correct and the Dec wheel is eccentric to the Dec shaft, the wheel in fact is rotating a 'cone' pattern which will lead to stripped teeth and a burnt out stepper motor.

Had it been a car, it would have been recalled and fixed at the car makers expense. So now we're been asked to 'fix' their problem?

So if you know any EQ8 users please make them aware of this.

cheers,

James

I'm sorry, but as an engineering universal precision grinder myself, that is totally unacceptable. 

[Alien 13]

I'm sorry, but as an engineering universal precision grinder myself, that is totally unacceptable. 

I agree that sort of error is unacceptable but what realy worries me is that if they had implemented some sort of spring preload in the system the fault would have been hidden but not resolved.