2024-06-16

South Plains Astronomy Club

Observing Under The Dark West Texas Skies

If your telescope controller has buttons that are difficult to operate, this is the procedure to clean the connections and restore normal operation.

At a recent star party, my original keypad on my scope died and I had to switch to a spare. It was a spare because the keys required excessive pressure and worked only occasionally. There is a solution to the problem, and it takes just a little time, patience, and care to fix it.

Meade Autostar controller
Meade Autostar controller

My telescope is a Meade ETX-125 using an Autostar I controller. I like the Autostars because they have features that (at the time) were not found on competing lines of telescopes. The other makes have caught up, but since I have several Meade scopes, I guess I’ll stick with them.

There is one problem with Autostars and they are rare and expensive these days. The older models are failing (as all electronics will eventually) and Meade is currently out of stock thanks to a supply issue. Since the primary failed and the supply dried up, I needed to work on the spare to get it working.

Supplies:

  • A set of small screw drivers to open the case
  • A clean pencil eraser
  • A few ordinary swabs (Q-Tips)
  • Alcohol (90% or higher preferred)
  • A static wrist strap is recommended

Procedure

  1. These instructions are for the Autostar I but will generally apply to most hand controllers with rubber buttons.
  2. Remove the cable from the controller.
  3. Attach your anti-static wrist strap.
  4. Remove the screws on the back of the controller.
    back screws to the Autostar
  5. Carefully open the back. Take care to not lose the red window at the top of the controller and be sure the board stays in the front of the controller. You should see something like this:
    The main board in an Autostar
  6. The next step is to remove the delicate ribbon cable. Before you work on it, here are a few warnings.
    1. These cables are very thin, with contacts made of conductive ink that can be damaged easily. Handle the ribbon only by the edge so the oils of your skin don’t touch the ink.
    2. The connector is also rather delicate and can be pulled apart if you use too much force. They use several designs. The one on this board isn’t damaged by pulling it apart and in fact, it fell apart as I was reassembling the unit, but some versions will break and become unusable.
      Autostar connector pulled apart
    3. To remove the ribbon cable, gently lift the tabs towards the display, which will release the cable. The cable should slide freely out of the connector.
      Remove the ribbon from the Autostar board
    4. Examine the contacts on the cable for damage and dirt. You can gently clean the contacts with a swab and alcohol, but don’t rub and don’t clean for very long.
      The delicate ribbon cable and connector
  7. Remove the board from the frame and keypad, then flip it over. Handle it only on the edges to prevent damage to the board from static and skin oils.
    Remove the Autostar board
  8. Use the eraser to gently clean the button contacts.
    1. Use light pressure and only a few wipes.
    2. Be careful with the small white LED between each set of contacts.
    3. You may see the contacts brighten a little if the contacts are really dirty. Notice how dirty the S13 and S11 contacts are to the left and right of the eraser:
      Cleaning the metal pads
    4. Blow off any eraser debris
  9. Now tackle the rubber buttons themselves. Wet some swabs with alcohol and gently rub the black buttons.
    Cleaning the rubber buttons
  10. It may take several passes until you don’t get much dirt on the swab. My contacts were dirty enough that it took about four tries on each button.
    Cleaning tools for your telescope handpad
  11. Once the alcohol has evaporated completely, place the keypad and board back in the frame, taking care to not trap the ribbon.
  12. Gently grasp the ribbon on the edges and slip it into the connector.
    1. Inserting the ribbon cable
    2. If you have trouble inserting it, check that the connector is fully open and try again.
    3. Once the ribbon cable is fully inserted, press down on the tabs and lock the cable in place.
      Autostar ribbon cable in place
  13. Replace the back, making sure the red window is secure at the top.
  14. Secure the back with the screws.
  15. Insert the cable and give the controller a test.

It can make a remarkable difference in the operation of the scope. This repair turned the nearly unusable keypad into working with a light touch!