Help. Mount RA Issues (AZEQ6)

[johnrt]

Hello,

I'm hoping someone can provide a little bit of inspirational thought on an issue that is slowly seeming to get worse and worse on my mount.

The mount in question is an AZEQ6 which I use in EQ mode only. This is my 2nd one of these mounts as the 1st one (bought from FLO) had an issue tracking in RA out of the box, it would spike in both directions seemingly at random. This was replaced immediatley by FLO (without fuss!). Here is an exampe guide graph from the original mount;

So on to incarnation 2, it is now 3 years old, so well out of any warranty. The mount was a little stiff out the box in both axis, but has worked well enough until recently, when it has begun to seemingly develop the same issue as the previous mount. Huge random spikes in RA, follwed by periods of flawless guiding.

I have checked the following;

• Balance / cables - the mounts guides for periods without issue between periods of spiking, so it cannot be this. A cable drag would need to be very lucky to always only effect the mount in just 1 axis!
• Power - the mount is powered from mains power, no dodgy batteries here.
• ST4 cable - I have seen these jumps in RA when the mount is not yet guiding, just tracking waiting for darkness or focussing up etc, so rules out the cables. I swapped it anyway just to see, but it made no difference.
• Clutches - the RA clutch is nice & tight
• Polar Alignment - is good, the mount guides well sometimes for extended periods between bouts of jumping around.
• Clouds - I have been by the side of the mount and seen this happen when there has been no clouds.
• Trains - I do have a train line that runs past my garden, but they go past every 20 mins almost all night, so this can't explain the long periods of good guiding. I have also seen the spikes happen when there are no trains passing.

Here are some screen shots of the last few times the mount has been used from the last month or so, there was also 1 evening where there were no issues at all, so I have not included. In all the examples below there were periods of excellent guiding before or after these bouts of spikes, without me making any physical changes to the mount balance, cables etc. The mount calibrates OK mostly (I have seen jumps when trying to calibrate), and then normally sets off guiding to begin with without problem.

This is from the end of a session, the mount had been guiding with no issues for the previous 3.5 hours.

This is the start of the same session above, the mount went on to guide for 3.5 huors before the next bout of spikes.

This next one was at the beginning again, worked without issue the rest of the (short) night.

Next one is an hour in to the run, worked fine for the rest of the run.

Next one again abut a half hour in, and lasted for a half hour before settling down to work well for the rest of the night.

 

As I say above, I have seen this every now and again for a little while, but it does seem to be getting worse and worse over time.

So on to possible solutions;

• I have re-flashed the motor controller firmware to the latest version on the Skywatcher website, but was only this morning so no chance to check if this has made a difference yet.
• The mount is run via EQMOD and a serial to USB cable - possibly try a new cable here?

This is hopefully where someone can jump in with some help.......

 

John.

 

 

[Dr_Ju_ju]

Hi John,

One quick question, why do you use the ST4 cable?, I just use pulse mode (which is the recommended way to drive the mount) with no issues...

[Starlight 1]

Still not got my mount right, I phone IK and he said you have to ajust the mount RA/DEC for summer and winter .

[johnrt]

1 hour ago, Dr_Ju_ju said:

Hi John,

One quick question, why do you use the ST4 cable?, I just use pulse mode (which is the recommended way to drive the mount) with no issues...

Old habits die hard I guess. 

50 minutes ago, Starlight 1 said:

Still not got my mount right, I phone IK and he said you have to ajust the mount RA/DEC for summer and winter .

I'm not sure what issues you're having, but the only adjustment I know of between seasons is to adjust for daylight saving if you use the handset. I'm running mine direct from a laptop so this is not needed. 

[Starlight 1]

PHD  stop working around every 5 to 8 mins in RA I got my mount last nov and only started to set it up this sep  I have adjusted the mount and back it right off this time and new  computer with phd . so to say you have to ajust summer and winter I think its a get out , hoping for some clear skys . ps I am running ST4 as well.

[Dr_Ju_ju]

As far as I'm aware there is no such thing as a Summer\Winter re-adjustment... I don't understand by what you mean "back it right off" ??

And I can only re-iterate, that the best way to control the mount is to drive it directly from the PC using a USB to Serial adaptor & in pulse guiding mode.

 

[Starlight 1]

17 minutes ago, Dr_Ju_ju said:

As far as I'm aware there is no such thing as a Summer\Winter re-adjustment... I don't understand by what you mean "back it right off" ??

And I can only re-iterate, that the best way to control the mount is to drive it directly from the PC using a USB to Serial adaptor & in pulse guiding mode.

 

Well I try what IK ask me to try. new computer/ back off the RA ajustments / and try pulse guiding .  Summer\Winter re-adjustment is a new to me as well.

[johnrt]

I have a new EQDIR cable on order from FLO, so I will see if that makes a difference. 

After replacing the cable I'm out of ideas, I would really appreciate anyone's thoughts or ideas!?!?

[billdan]

Looking at your graphs it appears the spikes are occurring just after a dither command. Maybe you could try turning ditheriing off and see if you still get the spikes.

Cheers

Bill

[Dr_Ju_ju]

Back to basics...

Run EQMOD\PHD but disable guiding (and disable the encoders), then see what happens over a period of time. If it still is an issue, I suspect that the mount requires a strip & clean.....

To get the latest EQMOD go to https://groups.yahoo.com/neo/groups/EQMOD/files/A EQMOD Release/EQASCOM/ but you will need to register to gain access.

[johnrt]

30 minutes ago, billdan said:

Looking at your graphs it appears the spikes are occurring just after a dither command. Maybe you could try turning ditheriing off and see if you still get the spikes.

Cheers

Bill

Thank you for the suggestion Bill, but I do not use dithering, these spikes mostly happen mid way through a sub.

9 minutes ago, Dr_Ju_ju said:

Back to basics...

Run EQMOD\PHD but disable guiding (and disable the encoders), then see what happens over a period of time. If it still is an issue, I suspect that the mount requires a strip & clean.....

To get the latest EQMOD go to https://groups.yahoo.com/neo/groups/EQMOD/files/A EQMOD Release/EQASCOM/ but you will need to register to gain access.

I will update PHD & EQMOD while I am at it, is there a way to disable the encoders without the handset attached? Perhaps a setting somewhere in EQMOD? I have seen the jumps before I have started guiding or calibrated, so I do not think it is PHD related.

I'm certainly not up to stripping the mount & re-assembling! Is there anywhere that does this as a service?

[Dr_Ju_ju]

That's why I pointed you to the Yahoo group, as there is a setting in the extended configuration screen to disable them, and there are other worthwhile fixes.....

& yes there are some tune-up services available, at a cost....  I just found the doc\videos & did it myself.

 

[billdan]

Well that is confusing, because the graph says settling started and then settling completed, you usually only see those types of messages when dithering.

 

[johnrt]

2 minutes ago, billdan said:

Well that is confusing, because the graph says settling started and then settling completed, you usually only see those types of messages when dithering.

 

I think this is SGPro stopping the current exposure due to the guide star going out of range, and then restarting when the mount recovers.

[billdan]

These intermittent problems are really hard to diagnose, I think you can discount software as being the cause and look for a hardware solution. This means someone has to open up the mount and have a look inside and see if there is anything obviously wrong, like a stretched or frayed belt or dirt on the worm or in the worm bearings.

 

[KemalOz]

From the graph it looks periodic, possibly a mechanical issue. have you checked the worm gear mesh? is there any end play? maybe it is time to change the bearings on the worm shaft. Because you don't have any warranty you can do open the mount now and while you're at it you can add/change grease too. It might also solve the stiffness while balancing. There are lots of tutorials online for tunning that mount, it might look scary but if you take your time you can improve performance.

[johnrt]

1 hour ago, billdan said:

These intermittent problems are really hard to diagnose, I think you can discount software as being the cause and look for a hardware solution. This means someone has to open up the mount and have a look inside and see if there is anything obviously wrong, like a stretched or frayed belt or dirt on the worm or in the worm bearings.

 

 

55 minutes ago, doramason said:

From the graph it looks periodic, possibly a mechanical issue. have you checked the worm gear mesh? is there any end play? maybe it is time to change the bearings on the worm shaft. Because you don't have any warranty you can do open the mount now and while you're at it you can add/change grease too. It might also solve the stiffness while balancing. There are lots of tutorials online for tunning that mount, it might look scary but if you take your time you can improve performance.

 

This is what I feared, I am really not comfortable opening up the mount, way beyond my level of expertise.

[KemalOz]

3 minutes ago, johnrt said:

 

 

This is what I feared, I am really not comfortable opening up the mount, way beyond my level of expertise.

ok then first check the worm gear mesh, that you can do from outside. maybe that will fix it, if not you can pay for hypertunning service. or sell the mount

[RayD]

I had a similar thing with mine John when imaging in any wind.  If I was imaging anywhere near the meridian and got a slight breeze I would get spikes similar to, but not as bad as, yours.  My AZ EQ6 from stock had what I would consider to be a very large level of backlash.  I adjusted the backlash out myself which is really easy and just takes a little patience and 2 allen keys.

Another thing to double check is to re-seat and tighten the cwt bar as the ridiculously small thumb screw thing on it has allowed mine in the past to show just a little play (that's all it takes).

I have the EQDIR cable from FLO and it works perfectly, but then I never had any problems with the original serial one, so have kept that as a spare.

Hope you get it sorted.

[johnrt]

37 minutes ago, doramason said:

ok then first check the worm gear mesh, that you can do from outside. maybe that will fix it, if not you can pay for hypertunning service. or sell the mount

 

17 minutes ago, RayD said:

I had a similar thing with mine John when imaging in any wind.  If I was imaging anywhere near the meridian and got a slight breeze I would get spikes similar to, but not as bad as, yours.  My AZ EQ6 from stock had what I would consider to be a very large level of backlash.  I adjusted the backlash out myself which is really easy and just takes a little patience and 2 allen keys.

Another thing to double check is to re-seat and tighten the cwt bar as the ridiculously small thumb screw thing on it has allowed mine in the past to show just a little play (that's all it takes).

I have the EQDIR cable from FLO and it works perfectly, but then I never had any problems with the original serial one, so have kept that as a spare.

Hope you get it sorted.

I have checked the belts under the side cover and they are intact, the mount moves easily on the belt & cogs by my fingers as you would expect. There doesn't feel like there is play in the RA axis when I try to move on the countershaft. The counterweight bar is nice & tight.

MY EQDIR cable (from FLO) is a little old & has seen better days, so I am really hoping that this issue is with that!

The only tune & service I can see on Google is £529!!!!

[johnrt]

Got a clear patch here at the moment, and the moon is too bright to image so I am just testing guiding using pulse guiding instead of via the ST4 cable to see if that makes any difference. I'm unhappy to say that the mount is still throwing huge spikes in RA.

 

[lux eterna]

On 2017-10-04 at 18:08, johnrt said:

 

I have checked the belts under the side cover and they are intact, the mount moves easily on the belt & cogs by my fingers as you would expect.

 

Do not rotate the cog wheels with the belt in place. The stepper motors will generate currents into the driver electronics.

On 2017-10-04 at 18:08, johnrt said:

There doesn't feel like there is play in the RA axis when I try to move on the countershaft. The counterweight bar is nice & tight.

 

I bet my last Swedish Krona that the problem is just there. You should feel a small noticeable RA (and also DEC) play when you try to turn those by hand. Adjusting the mesh is very easy and you need to check it now and then if you want to get the most out of your mount. The play may change with temperature, and you should cancel it out by misaligning a tad in RA and DEC balance. RA unbalance should always be east = heavy, regardless which side the OTA is.

CS

Ragnar

[lux eterna]

...should have mentioned :

Another possible reason for the symptoms you have could be if the RA unbalance is wrong (west = heavy).

/Ragnar

[Zakalwe]

On 03/10/2017 at 14:34, johnrt said:

I have checked the following;

• Balance / cables - the mounts guides for periods without issue between periods of spiking, so it cannot be this. A cable drag would need to be very lucky to always only effect the mount in just 1 axis!
• Power - the mount is powered from mains power, no dodgy batteries here.
• ST4 cable - I have seen these jumps in RA when the mount is not yet guiding, just tracking waiting for darkness or focussing up etc, so rules out the cables. I swapped it anyway just to see, but it made no difference.
• Clutches - the RA clutch is nice & tight
• Polar Alignment - is good, the mount guides well sometimes for extended periods between bouts of jumping around.
• Clouds - I have been by the side of the mount and seen this happen when there has been no clouds.
• Trains - I do have a train line that runs past my garden, but they go past every 20 mins almost all night, so this can't explain the long periods of good guiding. I have also seen the spikes happen when there are no trains passing.

 

 

You've done a lot of the diagnostics that I would start with. If it was my i'd try and check all of the easy stuff before considering stripping it down or getting it serviced. It'd be gutting to spend £hundreds on a service to find out the control board had a dodgy solder joint on the power connector.

I would, though, suggest a different power supply to rule that out. Or even a small battery to rule out a power issue (a cheap 12v lead acid battery should only cost £20).

If the mount is jumping when not guiding then that sort of rules out a PHD issue. For completeness, I'd remove the EQDIR and run the mount just with the handset. Centre a star and let the mount track. If it still jumps, then the problem is in the mount and not with the EQDIR or PC.

Check all the mechanicals with a fine toothcomb. For example, is the saddle puck tight on the mount (my old EQ6 mysteriously loosened the saddle puck over the course of a few months). Try e-mounting everything and just put a finderscope on a dovetail. Centre a star and let it track. If it jumps then it's not a balance issue/loose tube rings.

Can you take off the plate that the control board is bolted to? Check for dislodged connectors- for example are the cables running to the motors seated correctly in their sockets?

Can you disable the encoders in the mount using handset?

Is the power connector on the mount solid? The AZ EQ6 has a much improved power connector compared to the crummy one on the old EQ6. I'd still check it closely. A new power lead will be only a few quid- well worth it to eliminate one more thing. Can you see the power connector on the control board? Do the solder joints look solid and shiny? No cold solder joint that has failed over time?

Take all the kit off and fast slew both axis. If the worm mesh is too tight then you'll hear the motor pitch change.

Again, rule out all the simple stuff first. Good luck with it.....diagnosing these sort of faults is tedious. Being methodical is the key.

 

[johnrt]

Thank you for the comments; all greatly appreciated. I will look at your sugegstions.

I have been running the mount with my new EQDIR cable from FLO this evening as a test. The cable is a welcome replacement to my old Hitech astro one, which had seen better days. The new cable also required an entirely new driver, so I uninstalled the old, rebooted and installed the new software.

While I'm not entirely confident it is fixed, the mount guided quite happily for aout 3 hours. There was a couple of hiccups, but I was watching the very excellent Ken Burns Documentary on Vietnam at the time, there is quite a bit of low scattered cloud flying about so that could well have been the cause of the guiding issues.

More testing and cheking required!