Diagnosing and fixing ASI2600mm disconnects

Eric

I have a frustrating problem at hand with my ASI2600mm where the camera will randomly disconnect and not communicate properly with NINA, I'm wondering if the main board is going out and needs to be replaced, but I'm having trouble replicating the problem. I bought the camera off the cloudynights classifieds in early July and did several imaging sessions with it overnight without any problems. I was originally using an AM5n mount, powered with the Pegasus 12v 10a power supply, then running a power cable from the saddle output to a Svbony power/usb box which supplied power to my mini-pc and the ASI2600mm. I have the EFW and EAF plugged into the ASI2600mm and drawing power from that. I sold the AM5n and switched to a iOptron HAE29c-EC, the AM5n saddle power output is listed at 5a by ZWO while the HAE29c saddle output is only 3a, I decided I'd run my power supply directly to the Svbony and then distribute from that to the mount, mini-PC, and camera. I also kept the usb connections from the cameras to the Svbony and then from that to the mini-PC.

Somewhere along the way I started having random disconnects between the ASI2600mm and NINA, at first I was just using one of the shorter USB3.0 ribbon cables from ZWO, it was an older cable so I quickly tossed that and hooked up a more robust new cable. Seemed to be fine for a bit, but started having more problems, eaf/efw disconnects along with the main camera. So I started to think the Svbony power box was defective and so I moved to connecting everything directly to the mini-PC utilizing the 2600mm hub to connect the EAF/EFW with the mount and guide camera connected to the PC along with the 2600mm. I also incorporated a power splitter so I could split the power from the Pegasus power supply, one cable running to the mount and one to the Mini-PC. Then I ran a power cable from the saddle output directly to the 2600mm since it only needs 3a supplied which is what the saddle outputs. I would think the Pegasus 12v 10a supply would be enough for all those things in that configuration.

There doesn't seem to be any rhyme or reason to the disconnects, last night I started the sequencer and it ran for 5 exposures, then it ran into the error and I saw it fail. I restarted the sequencer and then it ran for about 2 hours before encountering the error. From the NINA log this the sequence of errors it reports:

2025-08-17T22:40:50.4037|ERROR|ASICamera.cs|DownloadExposure|417|ASI: Camera reported unsuccessful exposure: ASI_EXP_FAILED
2025-08-17T22:40:50.4042|ERROR|ImagingVM.cs|CaptureImage|254|Camera download failed - Exposure details: Exposure time: 150, Type: LIGHT, Gain: 100, Filter: O
2025-08-17T22:40:50.4049|ERROR|SequenceItem.cs|Run|263|Category: Camera, Item: TakeExposure, ExposureTime 150, Gain 100, Offset 50, ImageType LIGHT, Binning 1x1 -
NINA.Equipment.Exceptions.CameraDownloadFailedException: Camera download failed - Exposure details: Exposure time: 150, Type: LIGHT, Gain: 100, Filter: O
at NINA.ViewModel.ImagingVM.<>cDisplayClass38_0.<<CaptureImage>b0>d.MoveNext() in C:\Projects\nina\NINA\ViewModel\ImagingVM.cs:line 236
--- End of stack trace from previous location ---
at NINA.Sequencer.SequenceItem.Imaging.TakeExposure.Execute(IProgress1 progress, CancellationToken token) in C:\Projects\nina\NINA.Sequencer\SequenceItem\Imaging\TakeExposure.cs:line 190 at NINA.Sequencer.SequenceItem.SequenceItem.Run(IProgress1 progress, CancellationToken token) in C:\Projects\nina\NINA.Sequencer\SequenceItem\SequenceItem.cs:line 249
2025-08-17T22:40:50.4058|ERROR|SequenceItem.cs|RunErrorBehavior|195|Instruction Take Exposure failed after 1 attempt. Error behavior is set to ContinueOnError. Continuing.

Today I remote into the computer and just set the cooling on to 10C so it's running around 50% during the day, started a looping exposure in NINA, tried moving the focuser in and out while the cooler is on and looping exposures, tried changing filters, tried slewing the mount. Nothing seems to trigger the error so I'm not sure how to diagnose this. Tonight I might try hooking everything up to an ASIAir and running a quick target run with that to see if it happens with that as well, I can also try changing the cables and not utilize the USB hub on the 2600mm just to rule out that aspect. I'm wondering if the main board on the camera is going bad, but obviously there's a lot of variables happening and it's hard to isolate just a single one as the smoking gun.

Anyone have any suggestions?

Tech@ZWO

Based on the diagnostic analysis, the root cause is preliminarily identified as power distribution issues (considering inevitable voltage drops across power transmission lines). We recommend implementing a dual-power supply test:1、Use one dedicated 12V PSU for the ASI2600mm camera.2、Use another independent 12V PSU for the ASIAir unit.3、Conduct continuous operation for 5+ hours to verify stability.

Eric

So just to follow-up, I did a couple different things:
Switched away from the Svbony power box and changed out some cables. I ran power with a splitter to the mount and the mini-pc and then ran power from the saddle output to the 2600mm. I also ran a new, original ZWO cable that came with the camera (red cable) and separated out the cables (messy) so there couldn't be any electromagnetic interference. I ran that method all night 2 nights ago with no disconnects and no problems.

Yesterday I managed to get the Svbony box replaced via Amazon with a new one, ran a 12v 10a power supply to the box with a native 2.5mm connector (no idea why Svbony decided to implement power input via a 2.5mm connected instead of the standard 2.1mm connector, the rest of their outputs are all 2.1mm connectors). I connected the guide camera, EAF, and EFW to the Svbony USB ports, connected the mount and 2600mm directly to the mini-PC and the Svbony to mini-PC. I also ran power output from the Svbony to the mount, mini-pc, and 2600mm. It all ran fine for a while, I then started doing some tilt troubleshooting using NINA's aberration inspector, after ₆ auto-focus routines I encountered a significant error with the EAF in that it would no longer respond to position change inputs. I tried swapping cables, plugging it directly into the mini-PC, swapping USB ports, etc. In some cases it wouldn't even be detected when trying to connect via NINA or ascom, ultimately I was able to get it detected via the ASIStudio app, the beep setting would work and it would beep when a movement input was issued (but wouldn't move). Finally I was able to get the app to change the position setting from "0" to an arbitrary "4000" and it would respond to movement inputs again.

After that I stopped messing around with aberration inspector and just ran a NINA sequence all night with no issues after that.

At this point I'm less confident in the Svbony power box, still not sure what was causing the intermittent disconnects/errors with the 2600mm. The new cable and new Svbony power box seemed to run just fine for 1-2 whole nights, but I kind of feel like it's just a wait and see in terms of it happening again. It's supposed to be very cloudy for the next 7-10 days, so I won't be able to really test via an imaging run for a while. I'll probably run some darks and flats session over the next few nights to see if anything changes.

Tech@ZWO

After your testing, we found that you can run stably without the Svbony power supply. Therefore, we cannot rule out the possibility that the power supply is insufficient or the cable is too long, causing signal loss. We recommend that you use the ASIAIR's native power module for power.

Eric

I'm not using an ASIAir, I'm using a Mini-PC and NINA.

Tech@ZWO

Eric We recommend that you use the ASIAIR's native power module for power.Because the power supply of supporting products is more stable, we cannot guarantee the power supply of third-party products.