EQ3 Pro Backlash

[Thalestris24]

Hi all

Just wondered if anyone has any instructions on how to adjust the DEC backlash on an EQ3 Pro ? I can probably figure it out but if there happens to be a comprehensive maintenance guide out there somewhere, that would be really useful! My Google searches only seem to return EQ3-2 stuff - not the same...

Cheers

Louise

[Cornelius Varley]

The last paragraph of the dual axis motor fitting instructions shows how to remove the backlash in the worm wheel

EQ3-2 dual axis motors

[lenscap]

I know this applies to the EQ3-2 not the Pro version but the Skywatcher manual referred to by Cornelius Varley says that you tighten  the small screw to reduce backlash

but detailed guides such as this one;

state the exact opposite. Confusing eh.

[Thalestris24]

28 minutes ago, Cornelius Varley said:

The last paragraph of the dual axis motor fitting instructions shows how to remove the backlash in the worm wheel

EQ3-2 dual axis motors

Thanks but as far as I can tell the eq3 pro 'architecture' isn't the same as the EQ3-2 which is why I specified EQ3 Pro...

This is looking down on the dec motor. I can see various gearwheels, and can also see some from below, but a guide would be useful

Only eq3 pro info please!!

Ta

Louise

[Cornelius Varley]

There are two types of backlash. The first is the mechanical play between the worm and gear wheel in the mount, this adjusted by the method described in the dual axis fitting manual, which applies to the EQ3 Pro. And the second is the play between the gear array between the motor and dec drive shaft.

[Thalestris24]

10 minutes ago, Cornelius Varley said:

There are two types of backlash. The first is the mechanical play between the worm and gear wheel in the mount, this adjusted by the method described in the dual axis fitting manual, which applies to the EQ3 Pro. And the second is the play between the gear array between the motor and dec drive shaft.

I think it's just guidance on adjusting the motor gears that I'm looking for. Maybe the worm mesh adjustment is essentially the same as the eq3-2 but I can't tell with the motors in situ. I may be wrong but It looks like to adjust the dec worm mesh requires removing both motors to gain access to the dec 'fine adjustment' block hex nuts - I don't really fancy doing that, if I can avoid it. I think I just need some guidance/help/instructions with removing/adjusting the dec motor - it's clearly different from the eq3-2. I don't want to start undoing things without a clear idea ahead of what I'm doing... But, if it comes to it, I suppose I can have a go.

Thanks

[Peter Drew]

Hello Louise.

I've just had a close look at our EQ3 Pro and it appears that the means for adjusting the worm/wormwheel mesh is as described in the earlier replies.

As you have already suspected, the motor needs to be removed to access the adjusters. The motor is held on by just one bolt in a slotted hole so shouldn't pose any problem to remove. When replacing it make sure that the gears mesh with little pressure and that the flat gear faces are in line.  Good luck.   ?

[Thalestris24]

35 minutes ago, Peter Drew said:

Hello Louise.

I've just had a close look at our EQ3 Pro and it appears that the means for adjusting the worm/wormwheel mesh is as described in the earlier replies.

As you have already suspected, the motor needs to be removed to access the adjusters. The motor is held on by just one bolt in a slotted hole so shouldn't pose any problem to remove. When replacing it make sure that the gears mesh with little pressure and that the flat gear faces are in line.  Good luck.   ?

Yeah, thanks - I think I appreciate that now... It's very difficult to tell just by looking at it! It's not clear how I adjust the motor gear mesh as opposed to the worm mesh? You can't really see the gears with the covered motor in place - or can I remove the cover somehow - without removing the motor? ?

Cheers

Louise

[Peter Drew]

2 minutes ago, Thalestris24 said:

Yeah, thanks - I think I appreciate that now... It's very difficult to tell just by looking at it! It's not clear how I adjust the motor gear mesh as opposed to the worm mesh? You can't really see the gears with the covered motor in place - or can I remove the cover somehow - without removing the motor? ?

Cheers

Louise

Yes, there are two small screws holding the motor cover on.

[Thalestris24]

1 hour ago, Peter Drew said:

Yes, there are two small screws holding the motor cover on.

Ahhh right - I couldn't see one of them cos it was in the shade, so to speak, and my cataracts make it difficult to see  Senior moment...

I've noticed that the whole assembly has a noticeable amount of play - scope, dec motor and puck, together rocks quite a bit with not much effort. Any ideas what would cause that? I suspect it's the reason for the excessive backlash... The motor gear looks quite well meshed - maybe a tiny bit of play.

Thanks

Louise

 

[Thalestris24]

Hi again

Just wondering how tight the 4 x 5mm hex bolts holding the worm gear should or shouldn't be? After adjusting the worm, everything still seems to run smoothly... Of course, I might have made the backlash worse! Anyone know any tricks for estimating backlash during the day? Otherwise I'll have to wait till I get a clear night - who knows when that might be...

Louise

[Thalestris24]

11 hours ago, Thalestris24 said:

Hi again

Just wondering how tight the 4 x 5mm hex bolts holding the worm gear should or shouldn't be? After adjusting the worm, everything still seems to run smoothly... Of course, I might have made the backlash worse! Anyone know any tricks for estimating backlash during the day? Otherwise I'll have to wait till I get a clear night - who knows when that might be...

Louise

Anyone?

[Peter Drew]

Hello again Louise.

I think provided that each of the adjustment screws are firmly nipped up the adjustment should remain as set. If you can find an object in the daytime that corresponds to the naked eye size of the Moon you could use that as a yardstick for assessing the backlash in degrees. Can't help you with the clear sky unfortunately.   ?

 

[Thalestris24]

45 minutes ago, Peter Drew said:

Hello again Louise.

I think provided that each of the adjustment screws are firmly nipped up the adjustment should remain as set. If you can find an object in the daytime that corresponds to the naked eye size of the Moon you could use that as a yardstick for assessing the backlash in degrees. Can't help you with the clear sky unfortunately.   ?

 

Ok, thanks. When I took the motor off and looked at the 5mm bolts, one was loose-ish. After 'adjusting' I tightened the 5mm bolts firmly. I hate worm adjustments as you can never tell if you've done it right and you end up wishing you'd never touched it... No sign of clear skies this week but you never know...

Cheers

Louise

[Thalestris24]

ps Does anyone have any info on eq3-pro hypertuning?? Just wondered

Louise