asimov
28-11-2010, 06:45 AM
Some of you might remember, some time ago I had a 'spot of bother' with this mount - The chip on the MC board decided to burn out on me. This chip just happens to regulate the variable slew rates on the DEC axis (rates 1-9) courtesy of the handcontroller.
Problem 1 -Slewing still works, however because the chip has gone kaput, it only slews at rate 9 (maximum). I'm guessing it's pretty obvious the massive pain in the rear trying to center an object in the EP or camera at max. rate....I'm a planet imager; a no brainer to work out it's a huge non event in good seeing at an FL of close on 9M :eyepop::lol:
Problem 2 - I can't get a replacement board from Celestron direct 'cause I don't live in the US, plus they want me to ship the mount to them. Hell will freeze over before I ship this thing back, it's out of warrantee long ago! I can get a board from the local distributor for the low low quoted price of 500 clams - Considering I know the board's worth about 100USD hell will freeze over twice before I'll do that either. Do I look stupid, or what?? :shrug:
Anyway here's my fix, made of available crap laying around in the shed.
Considering I only have to recenter a planet on occasion in DEC with a good polar alignment, I'll be doing that manually with a slow/mo cable.
I've stripped the gearbox on the motor & pulled out some idler gears. The gearbox is only used now as an extra bearing supporter: You can press the DEC slew button to your hearts content, you'll get nowhere :D
I pulled the gear off the motor/gearbox unit, but left the gear on the worm, giving me a nice ratio for hand centering. It's belt driven by a bit of bicycle tube; it's just the right size. Not too tight, putting excess side thrust on any bearings.
I'm in process of making a 16" skeleton frame planet imaging newt to wack on this mount. I don't reckon the EQ6 I'm using under the C11 would quite cut the mustard in this department:lol:
Enclosed is a pic of the 'tube drive' :rofl: And the gears the mount 'lost' in the process..
Problem 1 -Slewing still works, however because the chip has gone kaput, it only slews at rate 9 (maximum). I'm guessing it's pretty obvious the massive pain in the rear trying to center an object in the EP or camera at max. rate....I'm a planet imager; a no brainer to work out it's a huge non event in good seeing at an FL of close on 9M :eyepop::lol:
Problem 2 - I can't get a replacement board from Celestron direct 'cause I don't live in the US, plus they want me to ship the mount to them. Hell will freeze over before I ship this thing back, it's out of warrantee long ago! I can get a board from the local distributor for the low low quoted price of 500 clams - Considering I know the board's worth about 100USD hell will freeze over twice before I'll do that either. Do I look stupid, or what?? :shrug:
Anyway here's my fix, made of available crap laying around in the shed.
Considering I only have to recenter a planet on occasion in DEC with a good polar alignment, I'll be doing that manually with a slow/mo cable.
I've stripped the gearbox on the motor & pulled out some idler gears. The gearbox is only used now as an extra bearing supporter: You can press the DEC slew button to your hearts content, you'll get nowhere :D
I pulled the gear off the motor/gearbox unit, but left the gear on the worm, giving me a nice ratio for hand centering. It's belt driven by a bit of bicycle tube; it's just the right size. Not too tight, putting excess side thrust on any bearings.
I'm in process of making a 16" skeleton frame planet imaging newt to wack on this mount. I don't reckon the EQ6 I'm using under the C11 would quite cut the mustard in this department:lol:
Enclosed is a pic of the 'tube drive' :rofl: And the gears the mount 'lost' in the process..