Sky-Watcher EQ3 Pro Not working

[Allz_photograph]

Hi Guys,


I recently purchased a used EQ3 Pro, it worked perfectly for 3 sessions and then started having issues with the RA motor, it was jittering and not slewing at low speed but did slew on rates above 7. To make things worse, it would only slew in one direction at higher speeds... I removed the stepper motor and swapped it with the dec motor to check if it was a stepper motor issue.
After fitting the Dec motor in place of the RA it did the same thing.
I opened the Synscan controller and inspected it and found this on the control board? Has anyone come across such an issue before?

Does anyone have a Synscan handcontoller i can borrow to troubleshoot my rig?
I'm in Roxburgh Park, Melbourne.
Any help would be much appreciated,
Thank you!

[bojan]

Hi Ali,

This is MAX232 chip. serial communication.. very un-likely the cause of your problems.

[iborg]

Hi Ali


That is indeed a problem, but, I believe should should be fixable.


From the photo, it looks to me like that chip was not soldered on that side.



I have dealt with this (https://modulerepair.com.au/)company for repair of a central heating board, and they did a nice job, quickly and at a good price.


I just noticed Bojun's response, and he has far more knowledge than I do about this. I think still get it fixed.



Good luck



Philip

[bojan]

Looks more like corrosion..

Is this one une of your boards? Motor drivers are higher, next to connectors.

Maybe there are more corroded contacts, look near the motor drivers (those chips are closer to connectors on attached photo)...
B

[Allz_photograph]

Hi Bojan and Iborg,

The picture is the back of the synscan board, I'd there a way to attach a video to show the issue?

[bojan]

The images of the rest of the boards(s) would be more helpful for me to give you a better advice.

Your problem is definitely around stepper drivers (RA), because (to my understanding) other functionalities are OK, right?

It could be driver, it could be on-board connector, it could be corrosion on board. Or dried electrolytic capacitor.. list can go on.
I think video could be uploaded if you zip it first.. but the size limitation still remains.

Link to some online mass storage would be better.

[Allz_photograph]

Thank you Bojan, I'll take more pictures when I get home

[Allz_photograph]

Hi Guys,

Just an update, I picked a usb A to B cable on my home and connected the mount via EQMOD and Ascom, bypassing the controller all together.
The Synscan wasn't the issue.. I've taken a pictures of the control unit, I can't see anything obvious wrong with it.
Also uploaded a couple of videos of what it's doing.

https://ibb.co/xGjb1MJ
https://ibb.co/Xk2mBrF
https://ibb.co/hBXzRZN
https://ibb.co/Yhq8LVR
https://ibb.co/KbJrwQ0
https://ibb.co/3ydCFXz
https://ibb.co/Kw4CHPf
https://ibb.co/jTCMt4r
https://ibb.co/qNj7brd

https://files.fm/u/p86vepkfe
https://files.fm/u/p86vepkfe

[bojan]

So, motor is stalled-intermittent?
That looks to me as stepper driver issue...

[Allz_photograph]

I swapped the the ra motor with the working Dec motor and the Dec motor did the same thing?

[bojan]

That means motors are OK, it must be the connector on board or the driver IC.

One-direction slewing at only high speed may indicate one of the coils are not energized properly or at all..
I think it is time for a better and deeper look at this.. do you have any specialized electronics equipment, like oscilloscope ?
To replace this chip, specialized equipment is needed, I cant do it (it has a large cooling pad).

However, what can be done is to add this (https://au.mouser.com/ProductDetail/Trinamic/TMC5130A-BOB?qs=TiOZkKH1s2R9Wg4Pj3qxMw%3D%3D&mgh=1&vip=1&gclid=EAIaIQobChMIjvjkjMyj_QIVWw8rC h1fnQ0xEAQYAiABEgIQ0fD_BwE) and bypass the faulty IC.. again, it requires steady hand and microscope.


On the attachment, RA driver U1 is a prime suspect, data sheet is on the website


https://www.digikey.com.au/en/ptm/t/trinamic-motion-control-gmbh/tmc5130-stepper-motor-driver-and-controller-with-stealthchop

[Allz_photograph]

Hi Bojan,

No I don't have any electronic knowledge nor experience with this stuff, where can I take it to have it looked at?

[Allz_photograph]

Hi Bojan,

I just checked and noticed this on one of the boards you mentioned.

Should I attempt to clean with isopro alcohol and tooth brush?

[bojan]

This will not help, unfortunately..

I will ask around for someone who can help.

In the meantime, try Iborg's link.
https://modulerepair.com.au/

[Allz_photograph]

Hi Bojan,

Unfortunately it didn't work, I'll contact the company you suggested tomorrow hopefully they can help.

Thank you again

[bojan]

In case the IC replacement fails, there is an option - to replace the electronics with OnStep (https://onstep.groups.io/g/main), it could be cheaper at the end of the day.
And of course, bypassing of the U1 with this module (https://au.element14.com/trinamic/tmc5130a-bob/breakout-board-stepper-driver/dp/2840455?gclid=EAIaIQobChMIjbm2ioCl_ QIV2nwrCh1JNwTzEAQYASABEgKiZ_D_BwE&mckv=_dc|pcrid||pkw||pmt||slid||pro duct|2840455|pgrid||ptaid||&CMP=KNC-GAU-GEN-SHOPPING-PLA-PMAX) should be attempted first.

[Allz_photograph]

Hi Bojan,
Not really familiar with the options you've suggested, I dropped it off at the repair center in Ringwood today. Waiting to hear back from them.

Thank you

[Allz_photograph]

Hi Guys,

Just an update incase anyone else comes across such a problem.

After waiting weeks for the control box repair and then having to order a new one:shrug: the issue I had was a simple loose cable connection that wasn't apparent due to the wire shielding

[bojan]

:(

[Doubledark]

Ali, other than this issue; are you generally happy with the mount? ( I'm tossing up between GTi / EQ3 / HEQ5 )

[Allz_photograph]

Hi Steve, I'm literally a noob.. I had a celestron NextStar 5SE go to that I used just for visual and struggled with it when trying to get into astrophotography.
I bought the mount second hand and to be honest despite all the issues I've had it still works better than the 5se.

I did a hypertune on it while waiting for clear weather to test it out, I changed all the washers to push bearings.

Last night we had a 2 hour windows before the clouds rolled in and tried it out, I polar aligned and started guiding for the first time.. No idea if the guiding is good or not.. I don't know where was the best place to post the picture of the guide graph to get some feedback on how it's tracking and if I needed to adjust the worm gears even further.

Do you know if this is good guiding? I didn't have a chance to image and test it.

[Doubledark]

I'm even more of a noob at all this! I've sent the image off to friend that may be able to interpret the graph