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[mtoastro]

Hi,

Haven't had a need to post for a loooong time, since everything has been running smoothly for years. Thanks Tom for a nice piece of kit . But, eventually it was bound to happen that I'd run in to some sort of problems with my setup, which is:
EQ5 mount mount with custom 6:1 belt mod, AstroEQ DIY HW ver. 4.0 firmware 8.05, EQASCOM v200j with WIN 7 OS.

I started setting up for the coming season with polar alignment and checking guiding functions etc. Everything worked smoothly for 3 evenings then on the fourth evening the RA tracking and slews started acting strangely. And this happened during normal running of the system and not after a system boot or anything. I completed my third iteration of polar alignment (azimuth and altitude) and started to set the alignment model when the RA slew behaviour changed. When slewing ie. West the mount might start moving towards the East and re-pressing the West slew button again the mount might start slewing to the correct direction or not. Eventually after a random amount of tries the the mount would slew to the correct direction after initially trying to decide which way to move. The RA motor also makes a lot more noise than before. Also the tracking stopped working after this. When tracking, the motor would just switch direction after each step so basically it would stay in place.

My first impression was that, OK it's just Windoze acting up, so a reboot and retry. Same behaviour. Since everything was working just fine before, I thought that it's probably the stepper driver (A4988) that broke. Changed both drivers (even though the DEC axis was working with no problems) to no avail. Still the same problem with RA. Then I thought that, just maybe it could be a problem with the stepper motor so I switched the DEC motor cable in to the RA motor and it ran smoothly. So, not an issue with the motor. Checked the cables, they were OK. So after checking various connections and testing I came to the conclusion that it very probably is something with the control box. Still need to go through all the components that they are OK, but just in case I'm going to place an order for new ICs. I do have an other board without the ICs so once I get them I can check with a fresh setup.

I'm inclined to think that maybe the Atmel chip broke for some reason. Won't be able to say before I try with the new chips.
Software issues were ruled out by the fact that everything worked fine for multiple sessions with the 8.05 firmware and I also reverted back to the 7.4 version firmware to test and the the behaviour was the same.

Unfortunately I don't have any debug logs or anything yet.

If anybody has run in to similar issues and resolved them, I'm all ears.

BR,
Marko

[TCWORLD]

Sounds like a loose connection somewhere.

It could possibly on the RA stepper motor - if so it would likely be intermittent and orientation dependent.

Alternatively it might be on the direction pin from ATMega to Driver boards. You could try pulling the ATMega out and putting it back in - just in case the issue is caused by oxidation over time. Reseating the IC would help clear that away.

[mtoastro]

Thanks Tom.

I removed the ICs and plugged them back in a couple of times. Now I just need to wait until the weather clears in order to try it out again. If that doesn't help I'll have to go through the cabling again and maybe reheat the solders, but we'll see once I get to test it with the mount.

The motor itself works fine and the problem is not orientation specific. It can happen at anytime or at any orientation.

BR,
Marko

[mtoastro]

Problem solved

The root cause turned out to be a bad/loose connection in one of the leads in the cable routed to the RA motor. The problem was not apparent when measuring with a digital multimeter but manifested itself when more current was passed through the cable when running the motor.

Most likely the reason being the large temperature fluctuations during the years it has stood outside.

Anyway thanks for the input and clear skies to everyone.

BR,
Marko