EQ6 Pro Overhauling

As a part of the construction of our small urban observatory this last weekend we spend an afternoon to tune our EQ6 Pro mount. We stripped it down, we cleaned it, we greased it, we adjusted everythig that could be adjusted and we finally got it working in a perfect condition. It took us less than 5 hours and allowed us to  better understand its inner workings and to remove all the looseness in its gears.

To avoid forgetting which part goes where we filmed it with our cell phone and compact camera. We have created a video of the process in case it is useful for someone that want to dismantle his mount. Moreover, we have added lots of comments about the process below.

Comments:

• 00:13 - We loose the three headless screws for the dovetail.
• 00:16 - We can find several of those "fake" screws that hidden some inner parts of it. Some of them hide other screws inside or allow to check the gears to adjust them.
• 00:23 - Inside the holes there are three small screws that tighten a black part to the axis (see 00:46) . We must loose them.
• 00:31 - We remove those 4 screws.
• 00:38 - Each axis has 2 headless screws in oposite directions. They are quite important as they allow to adjust the worm gear and the main gear.
• 00:40 - We unscrew the counterweights shaft. Firstly we should unscrew the headless screws on it.
• 00:46 - In the upper part we unscrew the black part. It was quite tight, so we needed to use a nail and small hammer (see 4:31).
• 00:52 - We get the conic roller bearing out.
• 00:57 - We took all the main pieces in this axis. Take care because this may get difficult as they can get stuck with each other.
• 01:05 - We can see how the worm gear and main gear are put together. We saw the the grease in the mount was not a high quality one.
• 01:11 - The brakes for the axis use a small metal disc that can be lost easily. Just put it in its place.
• 01:24 - We remove the central axis.
• 01:28 - We continue with the second axis. We took the black part away (it has three silver screws) and the polar scope (you should unscrew it).
• 01:36 - We get 4 screws away (similar to (00:31).
• 01:38 - This is one of the 2 small headless screws to adjust the worm gear and main gear for this axis.
• 01:40 - We loose the 4 headless screws of the black part and we get it out. It was very tight so we had to use a big monkey wrench. We get the conic roller bearing out. Try to do it more gracefully than we did :-)
• 01:47 - We got the main body of the mount out.
• 01:57 - We dismantle the main body. The gears are quite similar to the ones in the other axis.
• 02:15 - We unscrew the circuit panel and unplug the three cables (2 from the motors and one from the central led). Now we can get inside the motors cavity.
• 02:23 - We got the mount teared apart into little pieces. Time to clean them up and begin to assemble it back.
• 02:39 - We use good litium grease to the gear. Probably there is no need to use such a huge amount of grease, but Antonio likes it that way ;-)
• 02:45 - We assemble the gears with the casing.
• 02:57 - We apply some grease to the gear that goes to the motor gear.
• 03:07 - We introduce the main axis. It may get stuck, so be careful..
• 03:14 - More grease to the conic roller bearing. We put it into place.
• 03:24 - We screw the black part (quite tight) and screw its 4 headless screws.
• 03:27 - We screw the four main crews of this part of the casing. Be careful because this is a very important step. We should adjust the two small headless screws in order to adjust the worm gear to the main gear but not so tight that the motor has problems to move it. When you tight the four screws the pressure of the worm gear and main gear may increase avoiding a correct movement of the motor, so you have to try different configurations of the screws to avoid looseness (and reduce backlash) and allow the motor to roll fluently.
• 03:32 - We connect the cables to the panel (02:15), we plug the control pad and try to move the axis. First we tried to move in slow motion, then at full speed. If the worm gear and main gear are too tight the motor will crack in a very unpleasant way. We tried several loops in each direction to test that everything was OK.
• 03:39 - Now we are going to reduce the other possible looseness in this axis: the one produced by the two gears near the motor. To do so you can unscrew the "ghost" screw (00:16) and with a flashlight we can check the gears. To adjust them you just have to loosen the 2 screws of the motor and push it a little.
• 03:47 - Here you can see how the gears were before the adjustment (left side) and after the adjustment (right side). You can see that before the adjustment there was some looseness in the gears (which produced some quite noticeable backlash)
• 04:07 - We put the axis into the main gear of the other axis. This is more difficult than it seems because it is quite tight.
• 04:14 - We put the axis back in its place.
• 04:24 - We put the rest of the casing and the white cilinder part.
• 04:28 - We screw the the black part and tighten the three headless screws (check 00:16).
• 04:37 - We put the 4 screws on, but we do not tighten them.
• 04:41 - We insert the conic roller bearing and the counterweight shaft (but we do not screw the headless screws yet). We tighten the four screws of the previous step and the two small headless screws in a similar way to 03:27 and 03:47).
• 04:55 - We tighten the headless screws in the counterweight shaft. Be careful because in this step the axis may become very tight. So it may be necessary to try and adjust it several times until it is tight enough (without any looseness) and soft enough to be moved by the motor. We check the axis at full speed in both directions.
• 05:00 - We adjust the dovetail with the three headless screws.
• 05:15 - We are ready to rock!