you will want to be able to reliably return to this same position in a future step.

Begin rotating your telescope in its Right Ascension or Azimuth axis (left-to-right) in a clockwise direction as seen from a vantage point directly above the telescope.

Troubleshooting Guide

Symptom
Possible Cause(s)

(Southern Hemisphere users should rotate in the opposite direction.) The first set of displayed digits should increase as the telescope is moved (you will see something similar to 000 ... 001 ... 002 ... 003, etc.). If the digits decrease instead, see the troubleshooting guide for help.

If possible, continue rotating the telescope through a full 360° circle. Verify the accuracy of the display by comparing it with the number of degrees you have moved in Right Ascension or Azimuth. At 360° you will see 359 or 0. Return the telescope to its starting point by rotating counter- clockwise. At this point the digits should return to 000. If instead they vary from zero by more than plus or minus 1, see the troubleshooting guide for help.

Now rotate the telescope in Declination or Altitude (up-and - down) from the zenith toward the Southern horizon. The second set of digits should decrease (Note: an apparently increasing value is actually decreasing if the sign is negative). If the digits increase instead, then see the troubleshooting guide for help.

The unit does not come on.

The display does not reflect the motion of one or both encoders.

One or both encoders appear to run in the opposite direction.

Moving telescope in one axis changes opposite encoder reading.

Bad warp factors, inaccurate operation.

Display shows ENCODER ERROR at times.

•Low battery (use only alkaline batteries)

•Mechanical slippage

•Incorrect encoder setup

•Bad encoder/cable

•Reverse mounting

•Incorrect encoder setup

•"Hung" German mount

•Swapped encoder cables

•Not polar aligned

•Incorrect encoder setup

•Incorrect initialization

•Not polar aligned

•Slew rate exceeded

•Bad encoder/cable

•Low battery

If possible, continue rotating the telescope through a full circle. Return the telescope to its starting point by rotating in the opposite direction. At this point the digits should return to their original 000 or 090. If instead they vary from the original value by more than plus or minus 1, then see the troubleshooting guide for help.

If you encountered no problems, continue on to the next section, USING YOUR COMPUTER.

Troubleshooting

Use the Troubleshooting Guide (below) to find possible causes then read the sections below for possible solutions. For a more in-depth troubleshooting guide, see the addendum Diagnosing MAX Computer System Problems.

Low battery. The MAX computer can be powered from any 7-15 volt DC (direct current) source. When the power supply is below about 6.5 volts, the display will flash

ENCODER ERROR.

If using an internal 9 volt battery, be sure that it is alkaline ("Alkaline" must appear on the battery casing). Due to potentially rapid voltage and current drops in other battery designs, they should not be used. This includes nickel- cadmium (NiCd) rechargeable batteries as well as carbon- zinc batteries).

Mechanical slippage. Verify that all appropriate setscrews and bolts are tight. Any gears or belts should not have slop (you should not be able to rotate the encoder shaft without turning the telescope — a belt does not need to be very tight to meet this criteria). You might want to mark the encoder shaft to determine if it rotates with the telescope as it should.

Incorrect encoder setup. Since the computer can be used with various encoder resolutions and gearing ratios, the software allows the definition of the resolution for both axes. If this value is set improperly, the result can be slightly to grossly inaccurate performance, and if set to zero, can make an encoder appear to be non-functional.

A separate sheet titled JMI Encoder Setup Sheet — Tics- Per-Revolution, included with your encoder mountings, lists the correct setup to use with your specific mount. Confirm that the MAX computer setup matches this sheet paying particular attention to the order and sign of each tics-per- revolution specification (see SETUP on page 11 for additional help).

Reverse mounting. If an encoder is running the improper direction, the simplest solution is to change the sign of that encoder's resolution as found in the setup (see SETUP on page 11). This should only become necessary if the encoder has been mounted in a manner contrary to that which was intended by the Encoder Installation sheet, or if the encoder installation is custom designed by the user.

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