LX90 12" declination gear Fork Arm cover removal

[Tris]

I have searched this but I could see nothing, so apologies, and please direct me if there is another thread.

My 12" LX 90 has a knackered 12v power inlet and needs a new control board, which I gather one can get from Meade for not too much money. But I can't get the old one out as I can't get the fork arm cover off. It's a one piece cover and there are two bolts at the bottom (which were missing anyway, and 4 screws inside the arm. I've removed those but the top of the cover is held by the declination gear. I've removed the tensioner, washer, outer clutch plate and spacer.  I cannot see how to remove the gear wheel. The inner clutch plate  has 2 pins from it onto which the outer clutch plate locates, and 2 holes through it, one of which reveals what looks like a hex bolt. I'm worried to undo it as I won't be able to get it back if it drops inside.

Can anyone tell me how to get the gear wheel off? (either as one large piece, or I suspect, separately from the inner clutch plate, which it sits around).  

 

[Davey-T]

You could try the Meade LX200GPS Yahoo Group, there are some files on dismantling stuff and some folk with experience of taking them apart.

Dave

[michael8554]

I think this covers it:

 

 

[Tris]

That's ever so helpful guys. It's really useful to be able to see what is behind the spur wheel, and that this is what I need to be doing. My problem (hopefully now the last problem), is that I seem unable to get the spur wheel off the inner clutch, which is the bit that he has already done prior to the beginning of this clip. I'll have a further look around... 

[Davey-T]

Do you mean the toothed wheel ? it's just stuck on with grease, takes a bit off wiggling to loosen it.

Dave

[Tris]

...and it's off! All the wiggling I could do didn't move  it. It needed a hook behind it, I used a small meccano-like bracket, but a bent coat-hanger would do, I reckon. 

All is now clear and I have ordered a new switch / "Computer Control" panel from Opticstar in Manchester for the princely sup of £26 delivered. I'll report back when I've got it back together.  I will clean and re-grease the declination gears, and I can also see that my predecessor has been in there, and lost a few screws (which isn't difficult to do). I've replaced those, so hopefully it'll be better when I put it back together then it was before. 

Thanks for the responses everyone. I'll report back to finalise the thread for the next person, hopefully with a good outcome. 

Edited July 27, 2018 by Tris

[Tris]

OK so to finish this off, putting in the new switch was easy but Opticstar (who sold it to me for a very reasonable £26) passed on some wrong connection instructions from Meade.  Any new switch will have 2 poles for the power, and then 10 poles on the other side (the old switch has only eight as on my picture above) - two of these ten are for the GPS and LNT. The switches on the older 'scopes will only have 8 poles.

So if your scope is older and doesn't have LNT or GPS, then the two poles to leave unconnected are the two at the other end of the switch from the power poles. I attach a photo of the new 10 pole switch correctly connected for an older LX90 with no LNT or GPS. The Meade / Opticstar instructions were to leave vacant the two poles at the other end of the 10 pole row. 

You can trust me on this. I did try it the other way - nothing went "Pop!" but nothing worked either. 

As an added bonus, this 'scope never worked on batteries, only on mains - don't know why - presumably another fault on the old switch. But with the new switch it will use either. 

Edited August 14, 2018 by Tris

[Tris]

FINAL FOOTNOTE

Completely out of the blue I suddenly got a chance to buy a 12" LX200, which I have quickly done. So I after all that I shall now be selling this 12" LX90 (complete with its new switch and control board). I don't think I've got enough posts up to use the selling area here, so I shall put it up on the AstroBuySell site at a reasonable price to get it out. 

[Jtee]

Just wanted to share this idea for removing toothed wheel as I had tried many other ways. I used a very strong twine and eased it around the wheel ensuring the twine engaged  between the teeth 

Edited February 29, 2020 by Jtee