4-27-09 [Mount Problems]
Well I had been reading about all problems that others had with
this type of equipment and have been thankful that I had none.
I've been using the LXD75 for a little over a year and a half and for
the most part It's been behaving quite well. However my turn came last
I had ordered a new set of Encoder wheels from LXD55.com and had
replaced the flimsy ones that came with the unit. After a
successful install I took the mount out to check out my Polar
alignment. The initial setup (two star alignment) went OK as
usual but when I parked on a star it just scooted across the field
of view, just as if I had the RA motor turned off. I could bring
the star back into the FOV but it wouldn't stay there. Slews to
other objects went OK but as before the star would leave the FOV in a
hurry. Obviously that killed the night as far as any imaging
The next day I tried all kinds of things to attempt a
diagnosis. At first I thought that perhaps the 497
controller was flaky so I rest it and tried again. No good. Next I
reloaded the firmware for the 497. That also didn't help.
The following day I looked at the RA drive. I brought the
Mount in the house and removed the cover so I could observe the encoder
and output shaft. I did a fake two star alignment and then noticed
that the encoder would move a bit and then stop. I could still
hear the pluses being sent to the motor but it didn't move.
Maybe the motor is bad? I swapped the RA and DEC motors but it still
OK something is jammed, I thought. I removed the RA motor box from
the mount again and placed it o the table. Again I told the mount to
go thru a setup which it did but now the RA motor kept on running.
No load on it this time. Perhaps the Worm and Drum were binding, I
though, but moving the worm gear with my finger it seemed smooth and
relatively free. I loosened the worm even more and again tried the motor
. No good. One of the people on the Yahoo AutoStar group suggested that
I hang the RA motor assembly on the DEC axis and try that. Did
that to no avail.
After all the testing we came to the conclusion that the RA
controller isn't working properly ( I hope that's it anyway). A call to
Meade and $150 later I should have the new RA Motor box in a week or two.
Meade only sells the complete motor assembly ( motor, control circuit,
and plastic housing).
For the time being I'm out of luck. Just have to wait.
5-23-09 But wait there's more!!!
Meade sent me the replacement RA motor box and I attached it to the
mount. It sort of worked but skipped while guiding. After which
the 497 gave me a PROC TRAP-2 error each time the RA was
suppose to move. I Took the cover off the RA box and turned
on the unit and one of the tiny transistors went up in smoke. I
think it was the driver for the motor. At any rate. I decided to
give to old box another try and to my surprise it worked properly.
I don't know why but I had reloaded the firmware on the 497, reset
it and calibrated motors. Perhaps one of those resolved the issue. Now
waiting for a clear night to check things out.
On a slightly different note I would like to share
with you what I used to touch up the paint on
the OTA of the LXD75.
As is inevitable, you will get chips in the paint so I searched
around for something to use to touch it up. I ended up at my
local Benjamin-Moore paint dealer who matched up the color
perfectly (Stonington Gray). We used the low luster Wood/Metal latex
enamel and the following formula.
goes on a bit light but when dry it matches perfectly. Now what
to do with a quart of Stonington Gray? I only
needed a few ounces. Oh well, Such is life!
(stay tuned for updates )