7 year old lx200 has a new lease of life.

Hi,
Last week it finally happened!, I turned the scope on and it didnt start up properly, the power meter was showing that it was drawing twice the power it should have been :shock: and the RA drive sounded like it was grinding a box of nails, when it worked at all !!
I took the RA drive apart expecting to find the work/gear binding or that one of the gear box teeth had broken, but I could find nothing wrong
This was looking like I'd finally been hit by a fault I couldn't fix.

I'd heard of telescopeservices a few years ago (not telescope-services) and contacted them regarding the problem, they have a very good rep for fault finding on these scopes.
www.telescopeservice.com/lx200.htm
They sent me back a PDF document on what might be the cause, I have access to an oscilloscope and so felt I could give it a go, and they were bang on the money!!!, I corrected the problem and now the scopes back in action, if this didnt work I was facing a very expensive fix for this, one almost not worth doing given the age of the mount.

If you have a lx200/gps and have a problem, these guys are your solution.

The funny thing is that the motor now sound better then it has for a few years, I'm going to do the same fix on the DEC drive even though its working, it does sound like it might be going the same way as the RA drive. Theres a bit of life in the auld scope yet.

Geat to hear you got it sorted!!

Well done Dave.
It's a great feeling when you get something like this sorted yourself!
......although it sounds like you're thinking of making a new purchase!?

I'll bet you're relieved Dave, fair play to them, there is nothing worse when a motor driving a good set up breaks down. Glad to hear it's fixed!

Keith..

I have to say it was a relief, although I am hoping to get a new mount next year.
All the same I wanted it to last until then.
I checked out the dec drive and it wasn't far from having the same fault, I made the same correction and its bang on now.

For those who are interested, this is what its about.

There is an optical encoder sending 2 pulses back to the scope computer, these tell the system how far the drive has travelled, be it a slew or just plain old tracking. If these pusles dont have a duty cycle of 50% (say below 20%) then the scope cant decide on what the drive is doing and starts doing erratic things with the motor which is indicated by high power drain on the power meter and wierd noises. The way to fix this is to adjust the motor board "pots" so you get the 50% back, very easy once you know why and how.