CEM70G USB hub fix.

[paul]

USB hub

Here are some notes on my ongoing issue with the hub and how I now believe it is fixed. Maybe it will help someone else.

 

The last few imaging sessions I've been using a direct USB-cable from the ASI1600 to my PC as the CEM70G's integrated hub seemed to be randomly disconnecting devices or not even detecting them at all. This was the culmination of steadily worsening symptoms which previously I had addressed by black magic power up sequences and swapping out cables etc. I feared the worst - having the mount caught in the rain last year I suspected the USB hub may have corroded in some way.

 

Unbolting the saddle from the mount allowed me to look at its underside where I could see two small hex bolts that hold the USB sub-system to the saddle. Removing those allows the unit to come away still connected to its cables.

 

I'm happy to say there was no evidence of corrosion on either side of the board - it looked pristine👍

A bit disappointed there weas nothing obvious, I connected everything back up. Before bolting things together I pushed all the connectors in firmly and checked the hub operation - every port was working with no hint of instability!

 

There are four connectors on the board, two multiway headers for cables that go into the mount (probably to the main controller board and possibly to the ipolar camera), one multiway header connects to the iguider camera, and there is a power connector.

 

Only the power connector has a locking mechanism, the rest rely on friction to keep the connectors in place. This is not likely a problem for the iguider as its connector is vertical off the board and the iguder doesn't move. However, the two connectors that go off in to the mount are edge connectors, there is nothing to clamp them in place except for a bit of foam to sandwich them between the saddle and DEC metalwork. The DEC moves relative to the mount...

 

I now suspect that over time the cables in to the mount have been tugged as the DEC rotated or perhaps temperature cycling has caused them to work loose a little. 

I put everything back together and retested - everything continued to work reliably. So, I'm back to a single USB cable with the ASI1600 working solidly through the hub - only time will tell if it stays that way. At least I know where to look if it happens again.

 

 

Edited February 13, 2022 by paul