Avalon Linear/EQ6 not responding to slew commands.

[ollypenrice]

Anybody had this? The mount is an Avalon Linear but, for this issue, it should be the same as the EQ6. (They have the same motherboards, handsets, software and motors.)

The mount turns on OK and the handset setup routine works normally. When you ask it to slew to the first alignment star it says 'slewing' but it isn't. The mount remains still and silent. (No grinding noises!)

We have done these tests:

Tried another handset. Tried control from PC and tried two EQ Direct cables when doing so.

Tried a new motherboard.

Any thoughts or experiences welcome.

Thanks,

Olly

 

[Stuart1971]

I had this in my DEC axis only on an EQ8 and it was the connection plug for that motor where is plugs into the motherboard…one of the wires had come adrift..

But you seem to have covered everything there and you would have re seated those plugs on the new m/board…so I am at a loss…🤔🤔

[bosun21]

Check the motor cables for continuity on each terminal as changing the motherboard should eliminate the soldered joints of the boards connection to the female connector. Worth checking them anyway.

[malc-c]

It's worth checking the solder joints as suggested, but seeing that Olly has tried an alternative motor board and still gets the same result would rule that out. Also I'm sure Olly would have pushed these connectors home when exchanging the boards. 

The fact the handset runs through its initial set up routine rather than reporting a "No response" message suggests the microcontroller(s) on the motor board is/are working and that serial communications are established.  The fact that it gives every indication that the mount is working fine but the motors are not running IMO points to either an issue with the driver stage of the motorboard, or with the actual motors which are the only things that have not been swapped out.

I have never seen the insides of one of these mounts, but if they use the same control boards as synta mounts (an EQ6 in this case) the the 33v that is fed to the motors is generated from the 12v supply.  With the motors connected it's worth checking if voltages are present between pins 1 and 2, and then again between 3 and 4 of the connector.  Again, the fact that two motorboards would rule a failure of the A3959 driver chips, so my focus would be to check the wiring between the connectors of the stepper motors and the steppers themselves. The pairs of coils of the motors are between 1st and 2nd, with the second between 3rd and 4th pins of the connector, worth checking with a DVM to see if there is an open circuit by removing the connector at the board and test the pins in the connector.  Also check any intermediate connectors between the board and motors if there is an intermediate connectors.

If the motors and cable harness check out then I too am at a loss, and would suggest Olly contacts the retailer for advice, or Avalon's technical services as there may well be other test points that can be checked

[Froeng]

Have you tried slewing the mount with the directional buttons on the handset (ie manually)?