The HEQ5 is a good sturdy mount from SkyWatcher which uses quartz crystal drive motors. These are OK for basic tracking, but the GoTo Upgrade Kit installs more precise stepper motors and adds the GoTo hand controller for better alignment, tracking and location of objects.
The GoTo Upgrade Kit contains a new control circuit board, hand controller, two stepper motors, new gears, a polarscope illuminator, control panel, cables, grease and tools.
The first step is to remove the old components. This is done by removing the main side panel by unscrewing the 6 phillips screws as shown in the first picture. This reveals the original brass gears and motors, and two more phillips screws at the top. Turn the mount over and there are another two screws to undo. This allows the top cover to be removed which gives access to the control board and wires.
You can now unplug the cables from the control board and remove the original motors and gears using the supplied allen keys.
There are two screws holding in the control board, which once undone will allow the circuit board to slide out once everything has been disconnected. There are two small screws on the underside which hold on a plastic cover at the base. These should be removed and the plastic cover is replaced with the new control panel from the kit. You can feed the wire up through into the main area and replace the screws.
You can now insert the new circuit board into the case in the same place as the old board with the edge containing the white connectors facing up. It will screw back in place the same as the old board. You should also install the circular polarscope illuminator as well.
You can now insert the RA and DEC motors into their respective housing, remembering to feed the wires through and upto the control board. The gears can also be installed on the worm drive. The gears are identical, but remember to align them on the shaft so that the tightening screw is located on the flat part of the shaft.
You can start screwing down the motors, taking care to ensure that the gears mesh together fully, but are not too tight that they will cause wear. The holes in the mounting brackets allow you to move the gear in and out. There should be a little gap between the gears but not too much. You can turn the gears manually to ensure that they move freely, then tighten everything down and recheck. You should now grease the gears using the supplied tube of goo, ensuring that you do not use too much. By spinning the gears you can ensure that each gear has a little grease. This will prevent the gears from sticking during operation and ensure smooth movement.
You can now connect all the wires to the control board as shown in the picture below.
All that is left to do now is attach the covers, plug it in and try it. I would suggest a trial run indoors before setting it up outside at night. It would be a good idea to get familiar with the controls in daylight.