ASI 533MC Pro USB hub connection failures with multiple devices - Forums

Hi there,

I’m having some issues with my ASI 533MC Pro. Anything I connect to the USB Hub of the camera ends up getting disconnected because of connection failure. It does not matter if it is the guiding camera (ASI 220MM), the automatic focuser (EFA Pro), the filter wheel (EFW 5x1.25") or the mount (Sky-Watcher EQ-AL55i Pro SynScan GoTo WiFi), it will repeatedly get disconnected and fail. If I connect those directly to the Asiair Plus 256GB, it works just fine without failing, with the same cables, so it seems like the only possible failure point is the camera.

Has anybody experienced something similar? Any suggestions on how to fix it?

Thanks,

Dioni

Never works, ASI cameras USB hubs are notorious for that.

It could be a power issue. How do you have it set up.

Dave Stearn · Jun 5, 2026, 03:55 PM
It could be a power issue. How do you have it set up.

I use a ZWO power brick (12v, 10amp) into the Asiair and from there I power the camera with one of the provided cables and a heating element for the scope. The Asiair software reports there’s plenty of juice to spare, but not sure that’s the case.

That caused me problems as well. The inverter uses 15% more power. My set up is using a DC 12 volt plug connected to my Jackery battery. I used to have a 12v splitter one for the mount and the other for the ASIAir Plus. Now with the AM5N mount I just have one DC plug connect to the battery and power the ASIAir via the AM5N saddle. I have an all weather extension cord that charges the battery. The inverter on the power brick was causing disconnects.

Dave Stearn · Jun 5, 2026, 04:08 PM
That caused me problems as well. The inverter uses 15% more power. My set up is using a DC 12 volt plug connected to my Jackery battery. I used to have a 12v splitter one for the mount and the other for the ASIAir Plus. Now with the AM5N mount I just have one DC plug connect to the battery and power the ASIAir via the AM5N saddle. I have an all weather extension cord that charges the battery. The inverter on the power brick was causing disconnects.

Interesting… and I bought the ZWO branded one thinking it would solve me some issues 🤦‍♂️🤦‍♂️🤦‍♂️

In my experience, ZWO has marginal USB capabilities, and you are way deep in the ZWO barrel of apples. I use a powered USB hub. (Startech)

I had a problem with a ZWO focuser (EAF) and they jacked me around enough I have sworn off of ZWO equipment. I like my ZWO cameras so far, but do not plan on buying anymore when mine quit. I replaced the EAF with a much better Pegasus Astro focuser.

Dionito · Jun 5, 2026 at 04:27 PM
Dave Stearn · Jun 5, 2026, 04:08 PM
That caused me problems as well. The inverter uses 15% more power. My set up is using a DC 12 volt plug connected to my Jackery battery. I used to have a 12v splitter one for the mount and the other for the ASIAir Plus. Now with the AM5N mount I just have one DC plug connect to the battery and power the ASIAir via the AM5N saddle. I have an all weather extension cord that charges the battery. The inverter on the power brick was causing disconnects.
Interesting… and I bought the ZWO branded one thinking it would solve me some issues 🤦‍♂️🤦‍♂️🤦‍♂️

Once I stopped using the power brick all my connections issues stopped.

SonnyE · Jun 5, 2026, 04:40 PM
In my experience, ZWO has marginal USB capabilities, and you are way deep in the ZWO barrel of apples. I use a powered USB hub. (Startech)
I had a problem with a ZWO focuser (EAF) and they jacked me around enough I have sworn off of ZWO equipment. I like my ZWO cameras so far, but do not plan on buying anymore when mine quit. I replaced the EAF with a much better Pegasus Astro focuser.

I am very happy with their equipment in general, but I’m pretty new in all this, barely 3 months since I bought the telescope and the imaging stuff. I think going their route helps with the learning curve, but agree the EAF is not great, much less being used to super fast AF from DSLRs and mirrorless cameras, lol

Also worth checking the usb cable connecting the camera/hub to your asiair.

Zwo usb cables don't have a great rep :)

TiffsAndAstro · Jun 5, 2026, 04:56 PM
Also worth checking the usb cable connecting the camera/hub to your asiair.
Zwo usb cables don't have a great rep :)

My guess is that cable is good because I have no problems at all with the 533 connection and pictures transfer to the ASIAir, but I will try replacing with another USB 3 cable, if I can find one around, and see what happens.

Dionito · Jun 5, 2026 at 04:59 PM
TiffsAndAstro · Jun 5, 2026, 04:56 PM
Also worth checking the usb cable connecting the camera/hub to your asiair.
Zwo usb cables don't have a great rep :)
My guess is that cable is good because I have no problems at all with the 533 connection and pictures transfer to the ASIAir, but I will try replacing with another USB 3 cable, if I can find one around, and see what happens.

You may want to try switching the Blue USB port for the camera.

In any case, my advice would be to use a 12V connection using a battery that can take a 12V like the Jackery 300 Explorer that I use. You can still power the mount separately.

Dionito · Jun 5, 2026, 04:52 PM
SonnyE · Jun 5, 2026, 04:40 PM
In my experience, ZWO has marginal USB capabilities, and you are way deep in the ZWO barrel of apples. I use a powered USB hub. (Startech)
I had a problem with a ZWO focuser (EAF) and they jacked me around enough I have sworn off of ZWO equipment. I like my ZWO cameras so far, but do not plan on buying anymore when mine quit. I replaced the EAF with a much better Pegasus Astro focuser.
I am very happy with their equipment in general, but I’m pretty new in all this, barely 3 months since I bought the telescope and the imaging stuff. I think going their route helps with the learning curve, but agree the EAF is not great, much less being used to super fast AF from DSLRs and mirrorless cameras, lol

Yeah, pretty new. I’m not.

This astro stuff won’t hold a candle to our DSLR equipment. You have all the “auto” broken into different components, so don’t compare or you will be disappointed.

Good luck with your ZWO stuff.

Second to all the above. The ASI Hub doesn’t maintain the voltage rail when there are current spikes from the camera or accessories. I’ve seen it with an oscilloscope. You should definitely have just your 533 and nothing else connected to a given USB port on your PC/ASIAir etc. In fact if you have the ability to make sure your camera is the only device on your PC’s specific hub controller, it and your accessories not on that hub controller will all have a more robust connection.

Dionito · Jun 5, 2026, 04:27 PM
Dave Stearn · Jun 5, 2026, 04:08 PM
That caused me problems as well. The inverter uses 15% more power. My set up is using a DC 12 volt plug connected to my Jackery battery. I used to have a 12v splitter one for the mount and the other for the ASIAir Plus. Now with the AM5N mount I just have one DC plug connect to the battery and power the ASIAir via the AM5N saddle. I have an all weather extension cord that charges the battery. The inverter on the power brick was causing disconnects.
Interesting… and I bought the ZWO branded one thinking it would solve me some issues 🤦‍♂️🤦‍♂️🤦‍♂️

And it probably will. The ZWO hub connectors I’m sure are the cheapest they could get. Setting you cables up with effective strain relief is important so that the cables do not put any strain or movement into the connectors.

Dave Stearn · Jun 5, 2026, 05:10 PM
You may want to try switching the Blue USB port for the camera.
In any case, my advice would be to use a 12V connection using a battery that can take a 12V like the Jackery 300 Explorer that I use. You can still power the mount separately.

Yeah, I have tried both of them, and it keeps failing in both. I think the issue must be the power not being stable enough. I will try tonight powering the camera from outside the ASIAir, as I do with the mount, but if not, I will keep only the EAF connected to the camera, because it’s the only part of the whole thing that will not get the sessions cancelled when/if it fails.

Dionito · Jun 5, 2026 at 05:27 PM
Dave Stearn · Jun 5, 2026, 05:10 PM
You may want to try switching the Blue USB port for the camera.
In any case, my advice would be to use a 12V connection using a battery that can take a 12V like the Jackery 300 Explorer that I use. You can still power the mount separately.
Yeah, I have tried both of them, and it keeps failing in both. I think the issue must be the power not being stable enough. I will try tonight powering the camera from outside the ASIAir, as I do with the mount, but if not, I will keep only the EAF connected to the camera, because it’s the only part of the whole thing that will not get the sessions cancelled when/if it fails.

My ASIAir Plus is powered via the 12v port. The ZWO 2600MC Pro, EAF and ZWO 174 mini guide cam are connected to the ASIAir Plus. I plug in AC to the battery during the summer to make sure the battery does not run out.📷 IMG_3920.jpeg

Dave Stearn · Jun 5, 2026, 05:36 PM
My ASIAir Plus is powered via the 12v port. The ZWO 2600MC Pro, EAF and ZWO 174 mini guide cam are connected to the ASIAir Plus. I plug in AC to the battery during the summer to make sure the battery does not run out.📷 IMG_3920.jpeg

With that battery you can power the ASIAir and then everything from it, including the mount, without issues? I need to buy one of those anyways for when I decide to take everything out of the backyard into darker skies, so buying one now would not be crazy. Do you know how long a session you can do with it?

Tony Gondola · Jun 5, 2026, 05:21 PM
And it probably will. The ZWO hub connectors I’m sure are the cheapest they could get. Setting you cables up with effective strain relief is important so that the cables do not put any strain or movement into the connectors.

Yeah, the cables are loose enough not to pull on the connectors, that is definitely not the issue. The HUB or the connector’s quality is a different story. At the beginning I thought it would be the connectors, but it would be weird that it fails for both, then, and that it disconnects and re-connects right away, although not fast enough not to make the computer stop the session if it happens at the wrong time (which by Murphy’s law will be always when it does)

Dionito · Jun 5, 2026 at 05:52 PM
Dave Stearn · Jun 5, 2026, 05:36 PM
My ASIAir Plus is powered via the 12v port. The ZWO 2600MC Pro, EAF and ZWO 174 mini guide cam are connected to the ASIAir Plus. I plug in AC to the battery during the summer to make sure the battery does not run out.📷 IMG_3920.jpeg
With that battery you can power the ASIAir and then everything from it, including the mount, without issues? I need to buy one of those anyways for when I decide to take everything out of the backyard into darker skies, so buying one now would not be crazy. Do you know how long a session you can do with it?

With the AM5N I power the mount and ASIAir.

During the winter here in AZ the battery will last the night and mid morning. With my previous AVX mount the battery would still have 25% power left at Sunrise. It depends on how much power your mount uses, dew heaters and how much your camera cooling fan runs.

I use one of these, as I had two for amateur radio use. Caveat: Opening the case voids the warranty.

After opening the supply, I plugged it into 110VAC after attaching a VOM to look at voltage output. The stock 14.1VDC is too high for the ZWO gear.

There’s a small potentiometer that can be adjusted to obtain a lower voltage, which I set at 13.3VDC. At 30 amps, you’ll not need another supply, particularly with the Anderson PowerPole connectors on the front.

Since using this supply for going on 18 months, I have not had a single disconnect or function problem at all. HTH

https://powerwerx.com/ss30dv-desktop-dc-power-supply-powerpole

I just bought a 2600 MM Pro camera and have the same issues with inoperable USB Ports. Connections through my ASIAIR+ work fine. ZWO says there is a firmware issue for the P25 samples but the new firmware has to be remotely installed. Still waiting. Very Annoying.

For comparison and FWIW, I have a similar setup with no problems.

ASI2600MM
Mele mini-PC (Camera connected via blue USB 3 slot only)
Camera hub connections to ASI174MM guide camera and ZWO Filter Wheel
Power to camera from home built power box, which powers everything (input selected from 12V LiFePo4 or A/C).

Cheers.

Paul Larkin · Jun 5, 2026 at 10:16 PM
For comparison and FWIW, I have a similar setup with no problems.
ASI2600MM
Mele mini-PC (Camera connected via blue USB 3 slot only)
Camera hub connections to ASI174MM guide camera and ZWO Filter Wheel
Power to camera from home built power box, which powers everything (input selected from 12V LiFePo4 or A/C).
Cheers.

Thanks. It’s my understanding that the issue with specific to the P25 samples. that said, Astrobin and Cloudy Nights has multiple threads with USB connectivity issues for many of their camera. I have the 183 MC Pro, 533 MC Pro and the 2500 MC Pro and only had connectivity issues related to power management.

Is your monut also connected to AsiAir? I had same issues until I separate mount power from AsiAir. Since then no problems at all.