I've had my LX200 now for about a year and for the most part it has work
really well. About ten days ago I was using my system and the system would
either continuously keep running in the east direction or it would not run
in the east direction at all. I had my laptop hooked up to it and I was
able to properly control the RA movement through the laptop and LX RS232
port. I called Meade and the technician and I agreed that this sounded like
a bad key pad. So even though I was slightly out of the warranty period
they shipped me a new key. The new key pad arrives and seems to work fine
in land mode (couldn't wait to test at night). Well, I went out last night
and every thing seemed to work fine until I linked the laptop up to the LX
and established the link. From that point on the LX demonstrated the same
kind of behavior, either no response from the E key or would just flat keep
running. All other keypad functions seemed to work ok and the laptop could
easily still control the LX. On one of the restarts of the system as soon
as the system went though its initialization it started slewing E and had to
be turned off. I went through the MAPUG topical archives and was unable to
find anything like this. I apologize in advance if this has already been
covered on the list. Has anyone out there encountered this before? Tom
Porter

-- [bsj] You need somebody with a little tech knowledge and preferably an
oscilloscope and a voltmeter.


If you look on my web site there is a set of electronic circuits that cover
most of the LX200,ie the external boards and the main computer board but not
the power input header or the keypad at present.If you go to the lx200 part
of my web page there are a set of circuits listed 1 to 9 get the image of
circuit 9 and print it or look at it in a program such as Paint shop pro or
some equivalent. If you look at the output pin of the device called MAGPIC
in the circuit with a voltmeter as the worm wheel rotates this will go
between +5 volts DC and zero volts DC for a short period in the rotation of
the worm. This is a magnetic hall effect device that checks the position of
the worm. If you also look with an oscilloscope at the pin 1 U2A and Pin 2
U2B there should be a set of square wave pulses on these outputs again at
five volt levels. If all these signals are there then it is most likely a
main board fault not on the motor header.It is possible for any one with
basic tech experience to service this part of the circuit,not the same for
the main board tho...

Sorry about the hi tech answer but I do not know any other way.

Brandon S. Jones

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