Balance V's Backlash

[ballaratdragons (Ken)]

My EQ6 suffers severe backlash in RA and a slight bit in Dec.

I went into the Backlash adjustment in the hand Controller and set it from RA-5,000 & Dec-5,000 to RA-60,000 & Dec 50,000 and it made no difference

My hand controller is Version 2.5a

I tried all sorts of settings in between and it made no difference.

What it is doing is, in RA, one direction slews instantly and stops instantly, like it is suppose to. Slew RA in the other direction and it takes about 2 seconds before it moves and when the button is released it keeps slewing for another 24 seconds!!!!!!!!!!

Dec is similiar but only keeps moving for about 5 seconds.

I ended up reducing the Dec to instant move & Zero drift after release , and RA down to instant move & 5 seconds drift by moving the counterweight waaayyyy down the shaft to a point where the mount is very off balance.

So off balance that the counterweight end swings rapidly to the bottom!!!!!

Is there a cure for this bad backlash (without pulling the mount apart. I am tooo scared to pull it apart), or should I just leave the counterweight very off balance?

Thanks

[Alchemy (Clive)]

what happens if you remove the hand controller and use an autoguide program with a usb adaptor....... just considering it could be your hand controller given it stayed on for 24 secs, that doesnt sound like a mechanical flaw

[mick pinner]

l'm not sure what the problem is although l would be guessing hand controller but IMO do not intentionally run the mount out of balance, apart from probably doing some serious damage you are only bypassing what is an obvious problem.

[ballaratdragons (Ken)]

Originally Posted by Alchemy

what happens if you remove the hand controller and use an autoguide program with a usb adaptor

Huh? How do you do that? How would I slew, GoTo, etc?

Originally Posted by Alchemy

....... just considering it could be your hand controller given it stayed on for 24 secs, that doesnt sound like a mechanical flaw

The object doesn't keep travelling at Slew speed. It slows at release of the button then slowly keeps moving for the 24 seconds.

Originally Posted by mick pinner

l'm not sure what the problem is although l would be guessing hand controller but IMO do not intentionally run the mount out of balance,

That is my concern, Mick. Running the mount waayyy out of balance.

Originally Posted by mick pinner

apart from probably doing some serious damage you are only bypassing what is an obvious problem

That's why I am asking for help in here. I don't want to bypass. My gears could get stipped!

[monoxide]

my HEQ5 was doing something similar to this until i turned the backlash settings on the hand controller to 0 now it works perfectly

[ballaratdragons (Ken)]

Originally Posted by monoxide

my HEQ5 was doing something similar to this until i turned the backlash settings on the hand controller to 0 now it works perfectly

Ahhhhhh, thanks for that tip. I had been turning them up, not down. The manual doesn't tell how to set for Backlash.

I'll give it a go on Zero

[h0ughy (David)]

0 is the way to go.

[ballaratdragons (Ken)]

Hmmmm, last night I set Backlash to Zero on both Axis. No change. It is exactly the same as when set in the thousands!

Fortunately I remembered to re-balance the mount first.

I don't know what I did, but my GoTo's are out again
I must have slightly moved the mount when I shifted the counterweight.

Anyhow, the slew drifting problem is still there.
When I grab the end of the counterweight bar, I can move the mount in RA a few millimetres back and forth!!! That can't be good.
Also the Dec moves about 1mm when moved by hand.

[matt]

Originally Posted by ballaratdragons

When I grab the end of the counterweight bar, I can move the mount in RA a few millimetres back and forth!!! That can't be good.
Also the Dec moves about 1mm when moved by hand.

I get the same thing with my EQ6 too, Ken.

I've checked all the screws and bolts etc and they're all fine.

Seems to be a little slop in these things

[h0ughy (David)]

Originally Posted by ballaratdragons

Hmmmm, last night I set Backlash to Zero on both Axis. No change. It is exactly the same as when set in the thousands!

Fortunately I remembered to re-balance the mount first.

I don't know what I did, but my GoTo's are out again
I must have slightly moved the mount when I shifted the counterweight.

Anyhow, the slew drifting problem is still there.
When I grab the end of the counterweight bar, I can move the mount in RA a few millimetres back and forth!!! That can't be good.
Also the Dec moves about 1mm when moved by hand.

Ken you might have to send it to Roger from bintel - he fixed that up for me originally when I bought it from Mick Pinner. might cost you a couple of gold notes

[danielsun]

Ken it seems that you may have major backlash in the gears.
I only adjusted mine a few days ago on my HEQ5, I adjusted the hand controller to the minimum and still had some major backlash in RA so I pulled the cover off and loosened the allan head adjuster screws on the motor just enough to be able to lever the motor gear back with the driver gear because it had too much play.: Just note that if you do this DO NOT re mesh the gears too tightly,they must have just a minimal fraction of play or else there will be too much strain on the bearings and bushes.
I have never pulled the cover off a EQ6 but I imagine it should be a fairly similar set up.
I'm sure that as soon as you pull the cover off you will see what I mean and will be able to wiggle the gears back and forth with your fingers to see just how much play is between the gears before you attack anything.

Hope this helps.

[ballaratdragons (Ken)]

Originally Posted by h0ughy

Ken you might have to send it to Roger from bintel - he fixed that up for me originally when I bought it from Mick Pinner. might cost you a couple of gold notes

Gold notes I don't have. I'll just live with the drifting slew

I have read the articles on pulling the mount covers off and adjusting for backlash, but I'm not game enough to take my mount apart.

[acropolite (Phil)]

Ken, here is something that may help, illustrated step x step tuneup instructions. I've got the same problem, what seems like excessive backlash and I intend to run through this procedure over the holiday break.

[ballaratdragons (Ken)]

Originally Posted by acropolite

Ken, here is something that may help, illustrated step x step tuneup instructions. I've got the same problem, what seems like excessive backlash and I intend to run through this procedure over the holiday break.

Thanks Phil.
I've seen that link before but never read it properly. I just read it right through and I must say, it scares the willies out of me!!!!

I'm not prepared to pull out the circuit board, motors etc

Looks like my mount will have backlash for a lot longer.

[Alchemy (Clive)]

Originally Posted by ballaratdragons

Huh? How do you do that? How would I slew, GoTo, etc?

doh .... i dont have goto didnt think of that

[monoxide]

mine had a bit of slop in it (i could move the tube about an inch either way in RA) and i thought the same Ken, but in the end i figured i didnt want to fork out for a new head because i was too scared to try to fix the one i had, and what would happen if the new one was the same

i didn't end up having to pull the whole mount down, just the 2 plastic covers over the gears and the motors, it ended up being a nut that was so loose it could have fallen off

it was one of these nuts behind the drive gear: http://farm1.static.flickr.com/174/4...16ccc77e_o.jpg
and it was causing the whole worm/shaft to rock back and forth

all it took was a few screws to take the covers off and a grub screw that was holding the RA drive gear onto the shaft, now its rock solid in both RA and DEC

[ballaratdragons (Ken)]

Originally Posted by monoxide

i didn't end up having to pull the whole mount down, just the 2 plastic covers over the gears and the motors, it ended up being a nut that was so loose it could have fallen off

I don't have any 'Plastic' covers

Originally Posted by monoxide

all it took was a few screws to take the covers off and a grub screw that was holding the RA drive gear onto the shaft,

Sorry, but you lost me there

What covers and what grub screw? All I see in the pic is a big retaining
nut.

[monoxide]

i haven't got an eq6 but the basic mechanics behind the heq5 should be the same.
when you move the mount back and forth in RA by hand can you see the shaft moving in and out at all where the retaining nut is? thats how i found out where my problem was

[ballaratdragons (Ken)]

Originally Posted by monoxide

i haven't got an eq6 but the basic mechanics behind the heq5 should be the same.
when you move the mount back and forth in RA by hand can you see the shaft moving in and out at all where the retaining nut is? thats how i found out where my problem was

Ahhh, yep I understand that bit. So if it's loose, just tighten the big retaining nut?

[monoxide]

yep, but if you have to tighten it make sure you don't overdo it.
one end of mine was so loose the retaining nut had nearly fallen off and that was hidden behind the RA drive gear on the heq5