Hi, Mark;

> Does
> anyone have any info on troubleshooting the serial interface of the LX200??
> If replacement is necessary would it call for main board replacement or are
> the associated electronics on the board behind the power panel?

The RS232 port on my 12" LX200 recently died. Everything
else workd just fine, however I could no longer 'Link' to the LX from
my computer using The Sky, Guide or Megastar.

After trying to obvious stuff like connectors I finally ended up
biting the bullet and sending the 'guts' of the scope back to Meade
for repair (a $200 pop, by the way). I asked Paul McAllister to let
me know what they found wrong.

The problem turned out to be a bad chip. Apparently U9 is the RS 232
interface chip on the motherboard. As I recall, it is the
ubiquitous 7404 DIP package. When they sent my LX 'innards' back I
check to insure that they had, indeed, replaced U9. They had. After
putting the scope back together everything was working normally again
so it looks like U9 was, indeed the culprit.

Take care if you intend to try a chip replacement yourself. The
motherboard is a high quality, multi-layer glass phenolic board with
very small, delicate etchings. Replacing U9 would require a reduced
heat iron to insure that the etchings would survive the process.

Hope this helps.

Clear skies.

Dick

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