Troubleshooting USB Issues

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Troubleshooting USB Issues


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Modern, high-speed astronomy cameras like those from Altair, QHY and ZWO are wonderful, but they do tend to push the USB system of your computer or laptop right to the limit. Sometimes they push it a bit beyond the limit and everything goes wrong, leading to strange bugs, crashes or application freezes. This post gives some guidelines and tips for avoiding USB problems or curing them if they do happen.

Step 0 - Check the settings

Some cameras have USB speed parameters, which you might need to adjust to let them use more (or less) of the available USB bandwidth in order to get satisfactory operation.

Step 1 - Back to basics

If you are having unexplained issues with a camera or other hardware the first step is to go back to the simplest setup possible. Remove any hubs, extension cables and other hardware and just connect the camera to the PC using the manufacturer provided cable. If the camera works fine like this then other problems you are seeing are very likely caused by USB cabling issues (see later section on USB Cabling tips). If you are still having problems, move to step 2

Step 2 - Update

Make sure you have installed the latest version of the manufacturer's drivers for your device and the latest version of SharpCap or other imaging applications. This is particularly important for recently released cameras which may not be supported in older versions

Step 3 - Check the cable

It's very rare, but now and then you get a faulty cable with a camera, or perhaps the cable might have been damaged in some way. Swap the cable for another one of the same design and similar length just in case. If you have a USB3 camera, check that you have a USB3 cable (they tend to have blue plastic inside the plugs).

Step 4 - Try a different port

To get best results, your camera and your computer's USB system have to work together at very high speed. Some cameras just don't get on with particular USB ports for reasons that are not clear. If your PC or laptop has more USB ports, try switching between them and see if you get better results in a different port. It may sound weird, but it's worked for a number of people because different ports on the same PC may have different types of USB controllers running them - the one's on the right might not work so well but the ones on the left might be fine.

Step 5 - Check USB controller drivers are up to date

If you have a USB3 camera and the camera is detected but you never get an image, out of date USB controller drivers could be an issue. Go into 'Device Manager' and look for 'USB 3.0 eXtensible Host Controller' entries. If you see a version of 0.97, try to find an update for that device to 1.0 which I've seen fix this problem.

Step 6 - Try a different PC

By testing on another computer you hope to work out if the camera itself is working correctly - if it works fine on another computer then the chances of it being faulty are very slim.

USB Cabling Tips

If your device works correctly when you go 'back to basics' with a single USB cable, but fails with more complex cabling, then read through the tips in this section.

1. Absolute Maximum Cable Length

The maximum allowable cable length between USB devices is 5m. This means the cable length from PC to device or from PC to hub or from hub to device. You can build longer lengths by using hubs (or active repeater cables, which are basically a cable with a built in hub). So, you could have

PC -> 4m -> Hub -> 4m -> Camera

to get a total of 8m and it would have a reasonable chance of working, but

PC -> 8m -> Camera

will not work at all

2. High Quality Cables will *NOT* allow you to exceed the 5m maximum length

The limitation isn't to do with signal loss along the cable, it's to do with signal timing and the speed the signals move down the cable. Cheap and nasty cables however may reduce the maximum length that works!

3. Practical Maximum Cable Length is *NOT* 5m

Experience has shown that while a 5m cable run will work pretty well for something with a low data rate - like a keyboard, mouse, mount or focuser, it doesn't always work reliably with a high speed USB camera. I have found that cables over 4m start to have problems for USB2 cameras and over 3.5m can give issues for USB3 cameras.

4. If possible, give everything it's own port

By far the most reliable way to get multiple USB devices working is to take each and every device back to the PC separately with no hubs involved. If your PC or laptop doesn't have ports for this then the second best option is to use a hub for low data rate devices (mount, focuser, filter wheel, etc) and to bring the cameras(s) back to the PC on separate ports.
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Re: Troubleshooting USB Issues


Post by turfpit »

If there are still problems after carrying out the above basic checks then try turning off the USB Selective Suspend.

See ... sb-devices. This is for Windows 10 but does apply to Windows 8.1 and 7.

If still having issues then please post the requested information for PC/laptop.

For the purposes of this thread, the simplest configuration is:
  • Capture PC
  • Camera
  • Manufacturer supplied camera cable
The tests and information gathering can be done inside and do not require a telescope or mount. Configuration information can be acquired using USBtreeview and Microsoft's System Information tool (msinfo32).

The following information is requested:
  • An image of the left hand panel of the USBtreeview window with nothing else (except maybe mouse and keyboard) connected to the capture machine.
  • An image of the left hand side of the USBtreeview window with only the camera connected to the capture machine.
  • A USBtreeview full report.
  • A Microsoft System Information report.
  • Camera capture settings file.
Why are these needed?
  • Nothing connected gives a baseline of all the internal devices (webcam, card reader, Bluetooth, wireless) which appear on the internal USB bus.
  • Camera connected will indicate if the camera has connected as 'S' (SuperSpeed=USB3) or 'H' (HighSpeed=USB2).
  • USBtreeview report gives additional USB information & the version of the drivers on the machine.
  • Microsoft report gives all machine details such as CPU, RAM, disk, model of machine. The exact model helps as the USB chipsets can be researched for known problems.
  • Camera settings complete the picture.
Download USBtreeview from

The Microsoft reporting tool is part of Windows and the program is called msinfo32.exe.

  • With nothing plugged in to the capture machine, run USBtreeview and use the Windows Snipping Tool to grab the left hand pane.
  • With the camera only plugged in to the capture machine, run USBtreeview and use the Windows Snipping Tool to grab the left hand pane.
  • From USBtreeview do File > Save Full Report.
  • From Windows Search Bar or a Command Shell (black DOS box) type msinfo32 then File > Save . The resulting .nfo file can be quite large (3000 lines & 2.5Mb on my desktop) so zip the file before posting.
  • Run a capture test with the camera cap on, the capture-settings file is needed.
No personal information is contained in any of these reports. If there are any difficulties uploading because of file size, then a dropbox type scheme will need to be used.

Post the 5 files into your thread.

If applicable, set the Cooling to Off and re-test. This reduces the camera's power requirement from the USB bus.

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