ASI 120MC Grinds To A Halt

[Stickey]

Hello everyone. This is my 1st post and I'm asking for some advice please. 

I have a 2nd hand ZWO ASI 120MC, the USB 2 version and I'm struggling to get it to run at speed for any length of time. It will start at perhaps 25 f.p.s, but within a few seconds,  the dropped frame count will rise quickly and the frame rate will drop to somewhat less than 1/sec.

My laptop is less than 2 yrs old, has superspeed USB ports,  Intel i5 processor and ssd disc.

This happens with both ASICAP and SharpCap and I've installed the latest versionsof these and the ASI drivers. 

I've played around with various parameters, admittedly without knowing what they do, but nothing really helps,  apart from 1 thing.

The only thing that made a difference is using a powered USB hub, but even then, it only improved in SharpCap. 

I also have a 120MM-Mini and it works like a charm without any tweaking. 

I've trawled the Internet and the problem has been reported more than I expected,  but most of the causes relate to older PCs.

Given that it runs fine in SharpCap with a USB hub,  I assume the camera itself is fine and that the slowness is caused by some very subtle setting somewhere. 

Did anyone know the magic to get an ASI 120MC USB 2 running at its intended speed?

[PeterCPC]

May sound silly but have you tried another USB cable/port.

[lukebl]

I’ve found that I get a much better frame rate using Firecapture rather than Sharpcap. No sure why that should be, but I think Firecapture is a nicer program anyway.

[Cosmic Geoff]

What is the exposure time? And are you using the full pixels? Both may have an effect on the frame rate. For instance, if the exposure is 100ms, you can't get more than 10 frames/sec whatever you do.

IIRC, there is some issue with the ASI120MC (older USB2 version) that gave trouble under some circumstances.

[Stickey]

9 hours ago, PeterCPC said:

May sound silly but have you tried another USB cable/port.

Peter - Yes,  I did try another USB port on the laptop but it didn't make a difference, but thanks for the suggestion. 

Luke - Interesting suggestion, I'll give it a try, thank you. But getting the same result from ASICap and SharpCap made me think that the problem was either with the camera or a low-level parameter in the laptop. 

Geoff - I generally used the Auto setting in both programs for the Exposure. I did try playing around with it a bit but it didn't seen to help. I'm surmising from what you say that to get 30 f.p.s., the Exposure needs to be less that 30ms?

I'll try again being more targeted at the Exposure to see if it helps.

IIRC? Do you have any inkling of what the circumstances were in which the USB 2 120mc  misbehaved ?

I appreciate everyone's help.  Thank you

[Stickey]

Bit of an update on the original issue. It seems to have resolved itself. I'm still not getting 30 f.p.s., more like 20.

But the good news is that I'm able to capture images and get some decent stars. Not sure why it's fixed itself - maybe just a driver issue. 

Thanks for everyone's help.  Long live the SGL community!

 

Mike