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HINT: USB - It's your laptop, not your mount!

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#1 Michael Covington

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Posted 05 December 2021 - 02:14 PM

I learned yesterday by direct experience that the USB ports on a laptop can be substandard when running on the laptop's internal battery, and that this can be affected by power-saving settings, which in turn can apparently be reset by Windows updates or driver updates, causing sudden onset of symptoms.

The symptom looked like a hardware failure in my iOptron mount.  Either "iOptron Commander cannot find any compatible iOptron devices" or, worse, from Windows, "The USB device you have plugged in is malfunctioning."

 

It was intermittent.  Occasionally I would get a good connection.

 

The problem ALWAYS went away when I powered the laptop externally.

 

It also never appeared with my other laptop, which is why I quickly concluded it wasn't the mount.

 

Other USB devices worked fine with the original laptop, but I didn't try a very great variety of them.  It's possible FTDI needs to tweak something in their Windows driver for the USB chip used in iOptron mounts and many other pieces of scientific equipment.  But right now the solution is to power the laptop externally, as I always do in the field.  (This is an older ASUS laptop with limited battery capacity.)

 


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#2 Michael Covington

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Posted 05 December 2021 - 07:48 PM

It appears that setting the laptop's battery power management to "high performance" may also give me reliable USB, but I'm not 100% sure.


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#3 psandelle

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Posted 05 December 2021 - 11:15 PM

Yeah, I always check Window’s Device Manager after any update and make sure the USB settings (hubs and such) aren’t checked to put the USB ports to sleep. That’s the killer.

 

Paul


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#4 arbit

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Posted 06 December 2021 - 12:17 AM

Another possibility - an old battery with limited life might not be able to reliably deliver the 5V/0.5A needed for the USB port to function with the FTDI chip. Other devices may have a higher tolerance.

Replacing the battery could also help.

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Edited by arbit, 06 December 2021 - 12:19 AM.

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#5 alphatripleplus

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Posted 06 December 2021 - 08:23 AM

Moving from Mounts to Astronomy Software & Computers for a potentially better fit.


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#6 Michael Covington

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Posted 06 December 2021 - 12:33 PM

My battery is in good condition and I think the problem was an excessively frugal battery power conservation setting.  

I do think it has to do with the ability of the laptop to deliver +5V power via USB.  Other USB devices (jump drives, etc.) were working OK, but I have not tried any that require substantial power.  I'm guessing iOptron is powering their FTDI interface chip from USB rather than from the mount (it can be done either way) and that my laptop isn't meeting its requirements.



#7 arbit

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Posted 06 December 2021 - 10:06 PM

If you have the inclination and time, USB testers are fairly cheap, at least by astrophotography standards:-)

With everything running on USB nowadays, I always keep one handy just in case.

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#8 Sacred Heart

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Posted 07 December 2021 - 02:08 AM

It don't take much to mess things up does it??   Hopefully, when you find the culprit it does not take much to fix.  Sure can drive you crazy though.      Joe



#9 Michael Covington

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Posted 07 December 2021 - 09:31 AM

Good suggestion, I'll put a USB voltage and current meter in line and see if there's a difference in what's being delivered, and also how much the mount is drawing.

 

From my point of view it's fixed -- I now know that I need to power the laptop externally, as I had almost always been doing anyhow (but not on the day I had the problem).  But it would be good to pin down the electrical parameters.



#10 Michael Covington

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Posted 13 December 2021 - 08:38 AM

Result:  The GEM45 (early model, without internal hub) does not draw any 5-volt power from the laptop's USB port at all.  It must be the laptop's USB signal levels that are out of spec in battery-saving mode.



#11 lphilpot

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Posted 13 December 2021 - 06:38 PM

I learned yesterday by direct experience that the USB ports on a laptop can be substandard when running on the laptop's internal battery, and that this can be affected by power-saving settings, which in turn can apparently be reset by Windows updates or driver updates, causing sudden onset of symptoms.

Absolutely. Whenever Windows updates were rolled out at work, one of the standard post-test tasks was to go through the test computers with a fine-toothed comb and take note of everything we found that had been reset or changed (and it was typically a significant amount, particularly in the area of power). We put as much as we could under GPOs to at least catch resets, but that's not really viable at home.


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#12 dayglow

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Posted 14 December 2021 - 08:26 PM

What does GPO mean ?


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#13 lphilpot

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Posted 14 December 2021 - 08:46 PM

Group Policy (object), i.e., rules typically defined in MS Active Directory that do all sorts of things with computers, access rights, etc., etc. In a corporate Windows environment, Group Policies in AD are obeyed to customize each login account's access based on their settings (and much, much, much more).

 

I'm no GP expert at all, but for a domain- and AD-less home network it might be easier to write a PowerShell script that examines various settings, confirms and / or sets them the way you want. Kind of a "quick reset" after patching.

 

But I was a unix admin before I retired, so PowerShell was something I pretty much stayed away from.  :)  You'd need actual Windows knowledge, not mine.


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#14 Michael Covington

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Posted 14 December 2021 - 09:06 PM

Ah, yes, I've used GPOs... just didn't recognize the abbreviation out of context.




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