CGE won't stop spinning in dec
Posted 07 July 2014 - 11:22 AM
Posted 07 July 2014 - 11:24 AM
Posted 07 July 2014 - 12:18 PM
Get some DeOxit and liberally spray the contact jacks and plugs while plugging and unplugging each connecter about 10 times. This will "wipe" any corrosion off of the contacts.
90% Of the time, this will correct the problem.
If this does not fix it, then next step is to open the top of the Mini-pier and pull the boards, and once again, spray all the contacts with DeOxit and replug a few times.
If the problem is that you can't even get past alignment, the last thing to check are the RA orientation switchs.
Take scope and weight off and move the RA shaft in an arc across its full range while listening to for the switch contacts making and breaking.
Starting from either end of the full travel, you should hear a click shortly after the mount travles from the stop.
As the saft crosses the plane if the north leg, you should here a click, and then just before you get to the other limit, you should hear another click.
Go back and listen for the clicks in the oppisite direction, paying particular attention to the click that occurs wat the leg crossing.
Now, move the saddle so that the DEC switch breaks and makes, which should happen when the saddle is pointed to 90 degrees DEC.
I would test several times.
If you fail to hear a click at any of these spots on ANY pass, you may want to adjust the travel of the switchs.
These kinds of switches should last 1M+ state changes so it is highly unlikely (though not impossible) that the switch has failed.
What usually happens is that the swicth moves slightly in its bracket so that the roller that follows the groove in the axis does not travel sufficently for the switch to make or break in one direction.
The adjustment is simple. Pull the cover and watch where the roller of the switch contact arm is on the ramp when it is making/breaking.
It will not make/break exactly in the center of the ramp in both directions.
The adjustment is simply to get it to break a bit before the end of the ramp in each dirction. You do this usually by loosening the screws that hold the switch and tilting it as necessary to get the roller to "average" out the break near the center of the ramp. This might sound confusing, but once you watch the roller on the ramp, it is easy to see what I mean.
If the cables don't do the trick, you might as well get a clock battery and have it on hand before you open the mini-pier because if you are going to pull the boards, you might as well change the battery.
Not promising that any of these are the problem, but most of the time, one of these will do it for you.
Posted 08 July 2014 - 09:27 AM
Posted 13 July 2014 - 04:50 PM
Posted 13 July 2014 - 05:30 PM
You can't. The mount must find it's starting or home position before it will go on to the initial alignment and start tracking. The mount will drive the DEC motor until the switch position is found.
Have you gone through all the troubleshooting of the home position switches?
- Verified by ear the switches are opening/closing?
- Adjusted the position of the switch on the DEC axis? (sometimes the roller/switch is stuck and simply changing the position of the switch causes it to release and start working). You normally don't adjust the position of the switch with the two little Phillips head bolts that go through the body of the switch ... you use the two small Allen head bolts that hold the plate the switches are bolted to. You can also (carefully) depress the switch while the mount is driving the DEC motor to see if the switch position was a problem.
- Verified electrically that the switches are opening/closing? (at the switch, then at the connector and then to be complete at the connector on the MC board in the pier).
If all that checks out you've verified the operation of the switch, the connectors, the external cable, and the wiring up to the MC board in the pier. The next possibility is the MC board itself.
Posted 13 July 2014 - 08:28 PM
Posted 16 July 2014 - 09:37 AM
I have looked inside but am just out of my element here. I'm a dob pusher...AstroCamp is next week and I would hate for this scope to be inoperable.
Posted 16 July 2014 - 09:42 AM
Posted 16 July 2014 - 09:47 AM
Posted 16 July 2014 - 11:26 AM
Posted 16 July 2014 - 12:48 PM
I also told Darren to move the saddle sideways and at startup instead of going to switch position to undo to accept position. This bypasses the micro switches all together...Carl
Yep, and very good advice.
Posted 16 July 2014 - 04:51 PM
Posted 17 July 2014 - 09:22 AM
Posted 17 July 2014 - 09:49 AM
For a variety of reasons the metal shell of the RJ45 cable connector doesn't always make good electrical connection with the metal shell of the socket on the mount. A little work (changing the shape of the connector, adding foil, etc.) improves this connection. This is unfortunately not the only failure in this area, there can also be solder joint issues between the socket and board supporting it for example.
Overall it's a fairly common failure, it's why regular Ethernet patch cables won't work (the ones that don't have the metal connectors), and it's one of the primary reasons that Gary Bennett's cable replacement/upgrade kits work so well (he completely replaces the RJ45 cables, connectors, sockets, and boards).