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 week.

 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 was concerned.

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 stalled.

 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.

LXD75 Maintenance:

 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.

 IT 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!

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