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| Above: Now we turn to the left fork arm. Its hollow space contains the electronics for the GPS receiver. Unplug the ribbon cable where shown. (You could, perhaps should, remove the board right now. I did not (see below) and I had no problems.) Drape the ribbon cable over the top of the fork arm and hold it in place with a bit of masking tape. The threads inside this screw-on retainer cap also contains thread locking compound, but we can’t heat it with a torch because it is made of aluminum, which melts (and actually burns) at a fairly low temperature. Using a light hammer, tap the center of the screw-on retainer cap two or three times - not too lightly, not too strongly. Then, with your assistant again holding the OTA, insert your spanner and turn counterclockwise until the cap loosens. Repeat the tap-and-turn procedure as necessary. The cap loosened for me without excessive effort after three taps. Be careful not to damage the circuit board with the spanner. Remove the cap and slide the circuit-board bracket off the left declination shaft. Put the circuit board into a Ziploc bag and set it apart from other removed items to prevent damage from heavy parts. |
| Below: Remove the four hex bolts that fix the arm to the base. You will need a best-quality (hardened steel) 3/8" hex driver of the type with a long shaft and a screwdrive-like handle (i.e., not a regular L-shaped hex wrench.) These bolts are very tightly seated, and hand force alone will probably not loosen them. Making sure that the hex wrench is properly seated in the bolt head, tap the end of the handle firmly with a hammer. Repeat for all four bolts. This should break the “lock” on these bolts and allow you to remove them with with hand pressure on the handle-hex wrench. After the bolts are released, and with your assistant still holding the OTA, carefully pull the arm away from the base, being careful of the wires. The OTA should now be free to slide away from the forks. The two flanges and their declination shafts are still attached, of course. Remove the three hex bolts from each flange and you have liberated the OTA. |
