Sky-Watcher EQM-35 Pro not slewing

[Astrocane83]

Hello this is my first post here and I'm hoping you folks can help. I bought my EQM-35 Pro brand new April of 21. I used it with no issues several times.   We finally got some decent weather and I broke it out tonight to test out my new Polar Scope. I won't get into the details of how things went but suffice it to say it could have been better. I connected up the mount and went to do an alignment and at first it came up with a com 1 error on the handset. I turned it off and reseated the handset cord on both sides and ran it up again. This time it initialized and we were off. I made sure lat/long were good and that the setup was correct. Then it asked if I wanted to do a 1 star alignment. Sure why not I was just testing out the polar scope tonight anyway so 1 star should be good. picked an object and told it to go to the object. Hand controller said it was slewing changing the numbers but the mount didn't move at all. I tried slewing with the handset to no avail. turned it off and back on still nothing. There's no sound no attempt for the motors to move.  Brought it back inside to test it. Reseated all connectors and still nothing. The handset says it's slewing when i tell it to GOTO but shows nothing when I try to manually slew it. I tried a different power supply and still nothing. 

Nothing has been done to the mount at all and it has been sitting in a spare bedroom so it's not like I had it in my garage  or anything like that.  I'm perplexed, I dropped a lot of money on the mount (a lot for me) plus I just bought a WO Z81 to mount on it.

I have swapped the cables and took the motor covers off and reseated the connector cables still nothing.

Any help you folks can give me would be appreciated.  I will be contacting Sky-Watcher on Monday if we can't get it resolved here.  I hope it's still under warranty.  

 

Thanks in Advance

Edited October 2, 2022 by Astrocane83

[Clarkey]

How are you powering the mount? SW mounts do seem a bit fickle about voltages.

[Astrocane83]

9 hours ago, Clarkey said:

How are you powering the mount? SW mounts do seem a bit fickle about voltages.

I've tried 2 power supplies one being the original one that I used and the other is a FlashFish 60000mHA. I am going to take it out today and use my car just for a 3rd check. 

[malc-c]

Its no so much the capacity of the battery it the voltage it provides.  Whilst the specs state 12v 3amp (tip positive), that 12v is the under load voltage.  Depending on the design of the PSU you may find that the voltage drops to 10 or 11 volts when both motors are running.  Now as you have the same issue when using the supplied power brick as you do with other supplies I would suggest you contact the retailer with a view of having the scope collected under warranty and let them test and repair or replace the mount.

[Astrocane83]

13 hours ago, malc-c said:

Its no so much the capacity of the battery it the voltage it provides.  Whilst the specs state 12v 3amp (tip positive), that 12v is the under load voltage.  Depending on the design of the PSU you may find that the voltage drops to 10 or 11 volts when both motors are running.  Now as you have the same issue when using the supplied power brick as you do with other supplies I would suggest you contact the retailer with a view of having the scope collected under warranty and let them test and repair or replace the mount.

The power supply i used is adjustable and I ran it up to 13Vdc and still nothing. I didn't want to go higher until i heard back from Sky Watcher or Highpoint scientific.  I'm sure it could handle 14Vdc but better safe than sorry.

Thanks.

[malc-c]

Re-reading through the post there is no mention that the handset displays the "no response" message when plugged in, so that suggests to me that the main board in the synscan unit is working as the microcontroller(s) are running and talking to the handset.  The fact the motors don't move suggests that it is either the driver chip section on the board that's blown, or and more probable a wire connected to the DIN plug or socket has broken off (wouldn't be the first time on synscan units for the EQ3/ EQM35 and EQ5).  here's an example of the same issue - scroll down to the last but one post on page 2

Check each wire behind the DIN sockets on the motor casings, and each cable for continuity. 

[Astrocane83]

5 hours ago, malc-c said:

Re-reading through the post there is no mention that the handset displays the "no response" message when plugged in, so that suggests to me that the main board in the synscan unit is working as the microcontroller(s) are running and talking to the handset.  The fact the motors don't move suggests that it is either the driver chip section on the board that's blown, or and more probable a wire connected to the DIN plug or socket has broken off (wouldn't be the first time on synscan units for the EQ3/ EQM35 and EQ5).  here's an example of the same issue - scroll down to the last but one post on page 2

Check each wire behind the DIN sockets on the motor casings, and each cable for continuity. 

I swapped the DEC and RA cables and it's still dead.  I never got a no response message but on the first power up I got a com1 error but after reseating the handset cable it cleared and initialized.

Thank youi

[malc-c]

So based on the last post, the handset initializes,  but setting the speed to 9 and pressing any of the directional keys, or selecting any target from the handset, the handset shows it slewing to target but the actual motors fail to run.  You've also tried swapping the two link cables yet still the motors fail to move.  I was going to say that this points to the motors, but we have yet not being able to identify if there is actually any voltages or pulses being sent to the motors from the synscan unit.  If you have access to a digital volt meter you could test the steppers as suggested in this article   If you get the resistances between each coil then this could suggest the steppers are fine, but the synscan unit is at fault.

Alternatively, contact the retailer and see about returning the handset, synscan unit and both steppers with all the cables, ideally under warranty if the scope falls within that time frame.

[Astrocane83]

4 hours ago, malc-c said:

So based on the last post, the handset initializes,  but setting the speed to 9 and pressing any of the directional keys, or selecting any target from the handset, the handset shows it slewing to target but the actual motors fail to run.  You've also tried swapping the two link cables yet still the motors fail to move.  I was going to say that this points to the motors, but we have yet not being able to identify if there is actually any voltages or pulses being sent to the motors from the synscan unit.  If you have access to a digital volt meter you could test the steppers as suggested in this article   If you get the resistances between each coil then this could suggest the steppers are fine, but the synscan unit is at fault.

Alternatively, contact the retailer and see about returning the handset, synscan unit and both steppers with all the cables, ideally under warranty if the scope falls within that time frame.

I do have a DVM and will give that a try and see what I get. I'm leaning hard on the syncscan unit being bad. I played with it some more today and each time I told it to GOTO the results on the hand controller were different. First time both RA and DEC slewed but only went about half way to the intended object. Second time only DEC slewed and it went about 20 degrees past intended object. The third time both moved about 15 degrees and stopped. I also took one motor off and tested again to make sure it wasn't binding and nothing happened.

[malc-c]

Well at least we're getting somewhere as you say the motors are running, but the direction / duration following an instruction is always incorrect.   If you've swapped the leads over, and checked the motors then there is little more you could do other than return the complete kit back to the retailer.