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Classic LX200 blows Fuses and Capacitor

Started by vjpapa, 12/16/2010 11:34PM
Posted 12/16/2010 11:34PM Opening Post
My 1999 Classic 10" LX200 started blowing fuses and one 25v capacitor near the 18v inlet on the front panel. I tried different amp fuses and replaced the capacitor but the results are the same. Any help would be appreciated.
John

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vjpapa's attachment for post 52453
Posted 12/17/2010 12:46AM #1
John Paparelli said:

My 1999 Classic 10" LX200 started blowing fuses and one 25v capacitor near the 18v inlet on the front panel. I tried different amp fuses and replaced the capacitor but the results are the same. Any help would be appreciated.
John

Exact same problem I saw on someone else's Classic 10" LX200. I fixed it for him by replacing not just that blown cap, but the adjacent cap and diodes, too. It was a very cheap fix and it worked.

Hope it helps!

Brian
Posted 12/17/2010 05:47PM #2
John - I found the schematic. I replaced C2, C3, C4, and D1. One of these caps is mislabeled in the schematic - it shows two C2s (one is actually C3). I'll send the schematic to you in a private email. Don't replace the fuse with a larger one - you might burn out more components.

Brian
Posted 12/23/2010 05:33AM #3
John,

Does the fuse/cap blow as soon as power is applied or does it take a while for them to fail? If it takes a while you might have a motor that drawing too much because something is binding up.

I can't give you any direct answers but I'll tell you a few things to try. First, look over the components very carefully in strong light using something to magnify the view. A long focal length eyepiece used backwards can be used as a loupe. Look for any bulging, blistering or discoloration of components. Also carefully look over all the small wires to be sure you don't have something pinched. There have been cases of wires being pinched on assembly only to short out sometime later.

If all looks ok, replace the fuse and cap but don't apply power just yet.

Using a flashlight unplug your dec cable and hand controller cable and check the pins in the socket to make sure they aren't bent and shorted. Just for the heck of it open the hand controller and check to see if the cap in there is blown too.

Unplug the power board from the motherboard BEFORE applying power. If nothing blows this should tell you the power panel is fine. Then try again with the motherboard plugged in but the motors unplugged from the motherboard. Then try it again plugging one motor in at a time.

Be gentle and careful with unplugging and replugging things as there are some fine wires involved.

Let us know what you find.

Go here too for tons of helpfull info on the LX200 Classics: http://www.mapug-astronomy.net/AstroDesigns/MAPUG/ArhvList.htm

Clear, sunny skies.
Tom Masterson
Coronado-Lunt-Daystar Solar Filters forum Moderator