Am I mad?....Fettling a new NEQ6 Pro mount

[Gtech]

First off, I do have an innate tendency to dissasemble and tweak things, I even pulled apart a brand new KTM 990 only weeks after I collected it from the dealership...anyhow, I digress!

Being new to astronomy, my SW190MN / NEQ6 Pro package arrived about a month ago and right out of the box I noticed it was quite noisy on fast slews. I also noticed a repetitive brr sound at medium slews. Furthermore, when fully loaded (scope, camera, guider etc) it had some noticeable backlash and axial movement in both RA abd Dec, although both axis seemed stiff when rig balancing. So yesterday, I decided to pull it apart, investigate and fettle!

In general, component quality was better than expected, however assembly was typical of China's "hit and miss" QA procedures.     

• Bearings were poorly lubricated (with chinese chip fat) and one had some minor surface rust on its outer race. The taper roller on the RA axis was dry and both taper were loose, hence the axial movement.
• Both worm drives were poorly lubricated, meshings were loose and shaft end plays were tight, hence the noise and backlash.
• Both motor spindle gears and idle gears had mesh play and were poorly lubricated. The Dec motor spindle gear was sitting proud of the idle gear by ~1mm, hence the brrrr noise.
• All casting housing mating faces had paint over spray.
• The RA casting had some porosity piting on one of bearing housings. I guess water had been trapped in the casting during manufacture which caused the bearing's outer race to rust.

So I set about cleaning off all the chinese chip fat, paint over spray and smoothed out the RA casting imperfections.

I used a quality Lithium grease on all components, not ideal but much better than the gloop it replaced.

Both RA and Dec shaft/bearing assemblies gluided back together much easier than they disassembled....so no rubber mallets were needed.

The Dec taper roller bearing collar nut was preloaded enough to remove any axial movement and then backed off slighlty. Howver, I decided to leave the RA taper roller collar nut slightly preloaded.

I adjusted the worm gears / shafts to minimise backlash and end play without over tightening. The motor spindle/idle gears were re-aligned and meshings were made just a little tighter.

I tourqed down all the flange bolts to a reasonable tightness, unlike the factory over tightening.

I reconnected the motors to the PCB, fired up the mount and went through some very slow 360 slews to check for any binding. None found, so I ramped up the speed to medium, did a few 360 slews and the brrr noise was gone. I then did some fast slews, on motor spin up/ down I noticed some spindle / idle gear noise but  once the motors were up to full speed, all I could hear was motor whine.

The strip down was started at around lunchtime yesterday and finished just after midnight.

I rechecked everthing again this morning and loaded up the mount (scope, camera, finder etc) and went through some slews. The mount seems much quieter, backlash is greatly reduced and there's no mount wobble!
     
Was it worth doing?  For me, yes!

I may have thrown the warranty out the window but I now know how the thing is made, halted any immediate failures that may occur and can rest assured that its assembled / fettled better than when it left the factory!  

Next on the list is to sort out the SW190MN ring mount flexure.

[Clockwork_Orange]

Nice one Gtech

If I send you mine how much would you charge to service it  .

I'd probably end up with a box of bits if I took mine apart and then end up having to selling it as spares.

John 

[gingergeek]

In fact I'm Hampshire if you want to "fix" mine 

[laser_jock99]

Good work & worth doing by the sound of it- the EQ6 benefits from a bit of TLC, tuning and well, outright modification

http://stargazerslounge.com/topic/187034-eq6-latitude-lug-modification-or-how-to-avoid-bent-bolts/?hl=%2Bputty#entry1951874

I have dismantled both of mine to fix various problems.

[jambouk]

Can you tune up my azeq6 too? There's still backlash though not much wobble, and i'm always worried about the Chinese fat in there.

How much would you charge?

James

[LeeB]

I have a similar mentality if you take it apart and rebuild it , then firstly you understand its workings and secondly you get the opportunity to correct mistakes before damage occurs. Well the eq6 strips down nicely and rewards the effort.

[sloz1664]

there has been a multitude of threads regarding refurbishing the EQ6 mounts. The best being Astro-Baby's EQ6 site. www.astro-baby.com

There is also a thread currently running in the DIY section on upgrading your mount to belt drive, to help eliminate backlash.

cheers

Steve

[StarryEyed]

If I want to buy a mount without issues which manafacture do I buy from?

I am thinking of getting back into astronomy, four years back I sold all of my kit (I kept my WO FD 80) and now need to do more than just casual quick peeks. From the ground up I know I need to start with the mount. There are lots of new mounts about in the last four or five years but all this talk of stripping down, mods and problems with motors (other threads) has made me realise that qhilst the design of mounts has moved on the quality control issues havent.

Third time around I just will not accept any lost time late at night due to these sorts of issues.

So whats to feeling then what are the odds on a new skywatcher mount needing a fix out of the box to make it work at its best.

Actually thats a thread.

[Gina]

It certainly makes you wonder!  May I say - great job of servicing there   I've done mods on my NEQ6 to make the PA adjustments work.  These mounts are certainly ol' rattle-bones as supplied.  Clearly the engineering design on the new EQ8 has been vastly improved over the 6 but the QA remains to be seen.  I wonder how many new EQ8 owners will strip them down for a service before they use them, if any   From what I can make out they seem to have fewer parts that might be troublesome.

[Gtech]

Having been plagued with cloudy skies for the last two weeks with it perhaps continuing for another week or so, I have decided to do the belt mod on the NEQ6.

My intial complete strip made a huge difference on how the mount performed however it wasnt long before the stepper gear train noise returned.

I've opted for a 12/47 gear kit from Beltingonline to keep the ratios the same as OEM build. I will also hypertune and replace the worm bearings with hybrid ceramics while I am it.

I started the strip last night and noticed that the DEC axis worm shaft is off centre with the crown ring by about 3mm.

On the original strip I removed the worm shafts from one end as to not upset their location. Having looked into this in greater detail I'm not happy with the offset as one bearing is half located on the threaded section of the housing. I'll need to mod one end cap to allow the worm shaft to move across.

On the RA axis crown ring I've also noticed a tight spot which I may lap out.

Although not entirely neccessary, I will also open out the housing apertures to give a lttle more leeway on the belt alignment and remove all the sharp edges.

I obtained a guided peak PE on the first rebuild at +/- 2.8 arcsecs although both the worms and stepper gear train added quite a bit of vibration noise.

Hopefully this exercise will see an improvement....I'll keep you all posted!

[sloz1664]

Hi John,

You don't need ceramic bearings, the poor ol' mount is never going to ramp up to several thousand rpm.

I replaced all my bearings with top quality SKF bearings & hyper tuned.It's now as smooth as silk.

I have the parts to upgrade to the belt mod but I ran out of time (a project for next summer, we're in imaging season now).

Keep us posted on the trials and tribulations of belt modding your EQ6.

cheers

Steve

[Gtech]

Hi Steve, I know hybrid ceramics are overkill, but they were actually cheaper than SKF bearings. My supplier had a part skateboard race set (5) left over which I got 2/3 price of 4 SKFs.

[r3i]

Hi John,

Tweaking the innards of an NEQ6 is a well trodden path and well worth doing as you're finding out.  If you haven't already done so, check out this thread on the Belting Online Mod kit as a couple of us have found that the worm gear flange needs reducing a little to ensure smooth rotation on the DEC axis: http://stargazerslounge.com/topic/197040-eq6-belt-mod-belting-online/?hl=%2Bbelting+%2Bonline

[tonedeaf]

If I want to buy a mount without issues which manafacture do I buy from?

I am thinking of getting back into astronomy, four years back I sold all of my kit (I kept my WO FD 80) and now need to do more than just casual quick peeks. From the ground up I know I need to start with the mount. There are lots of new mounts about in the last four or five years but all this talk of stripping down, mods and problems with motors (other threads) has made me realise that qhilst the design of mounts has moved on the quality control issues havent.

Third time around I just will not accept any lost time late at night due to these sorts of issues.

So whats to feeling then what are the odds on a new skywatcher mount needing a fix out of the box to make it work at its best.

Actually thats a thread.

where to start....

ok the neq-6 (the newer ones) should be better (the bearings etc) than the older ones...

but even than you shouldn´t lose time regarding any issues described above...

so the out of the box eq-6 is a good mount...

i don´t know how this is with other similar mounts....

on the other side, there is the posibility to tweak the eq-6 to perform even better...

as described above with "time-investment" from your side!

(but we astronomers should have enough time -> hey we are looking the whole time up to the sky)

as a side note, you will learn very much from stripping the mount -> how it functions, where to adjust....

back to topic...

thanks for the reminder...i should take the time to strip down my neq-6

[Gtech]

Belt mod complete and provisionally tested with the hand controller.

As others have found, the mod is pretty straight forward.

I extended the slotted apertures by ~5mm each end for the belts as they would have rubbed on the casing.

The 47 tooth gear did touch the DEC casing and so I reduced its dia by 0.5mm. I also re-aligned the worm shaft by removing 0.6mm off one end cap.

Measuring the various heights and thicknesses for the hypetune, I found that both axis were over packed by 0.5mm (one shim), thus the crown rings and worms were slighlty out of align. Once set correctly, I could minimise backlash with neglible tight spots on a full 360 rotation.

To adjust the belts I used a bladed screwdriver to lever the motors back and used a long thin allen key to check their tension. I may have over tensioned them a little but I will run as is, as they may well stretch.

I'm not sure that I really needed to replace the worm bearings, but the hybrid ceramics arrived so I put them in.

With hindsight I should have replaced the DEC taper roller with a quality SKF bearing as the OEM doesn't run that smooth and is dimensionally lower grade.

So far I'm very happy with the mod, no more gear noise on fast slews and less backlash.

I eagerly await a clear night to see if there's an improvement in guide accuarcy and PE.

Total parts cost was ~£100, time taken ~8 hours!


 

 

 
 

[kirkster501]

Good work and I am of a similar disposition.  I'd counsel against over-tinkering though.  Some things, like lens cells, need specialised testing tools to re-align if you break them open.

[Astr0nut]

Hats off to Gtech for pulling apart a brand new mount; gotta admire your style...

I've had my SW190MN/NEQ6 for a few years and having seen a few threads and Astro baby's guide, I now feel confident enough to start work! Backed off the dec. clutch bolt and found nasty black sticky guck, but fortunately things don't seem to be done up too tight... Thanks for the inspiration; got everything ready- I'm goin' in!!

[kingboya]

Hats off to Gtech for pulling apart a brand new mount; gotta admire your style...

I've had my SW190MN/NEQ6 for a few years and having seen a few threads and Astro baby's guide, I now feel confident enough to start work! Backed off the dec. clutch bolt and found nasty black sticky guck, but fortunately things don't seem to be done up too tight... Thanks for the inspiration; got everything ready- I'm goin' in!!

How's it going?

[Astr0nut]

Thought I'd start off just doing the dec. axis as I was beginning to have trouble balancing the scope accurately. Everything came apart fairly easily, this mount is an NEQ6 (purchased Sept.2009), which would appear to be put together a bit more sympathetically; the counterweight collar was tight but not outrageously so, and the worm roller end caps on the worm carrier are actually made of plastic on this mount so no corrosion to seize them tight. As in Astro-baby's account the taper bearing was rather dry and was cleaned and lubricated with white Lithium grease + Teflon as was the worm gearing. The dec. shaft was withdrawn fairly easily, but has fine tolerance with the bearing races so was most careful not to force the issue. All other sealed bearings appeared in good order so were left well alone. Everything went back together OK and guess what...? No bits left over at the end!! Tuning was straightforward, just a little binding at fast slew which was soon tweaked out. In all the job took about three hours, not rushing at all. Gave myself plenty of space and light. Very pleased with the results so far; the mount is much quieter especially at faster speeds and all clutches and clamps are nicely freed off. Will be addressing the RA axis in a few days; hope this goes as well!