Problem with PHD2 and new handset

[almcl]

My new upgraded handset arrived promptly thanks to the nice chaps at FLO and for visual use works fine.

(threads here  https://stargazerslounge.com/topic/260824-disaster-night/?do=findComment&comment=2856443  https://stargazerslounge.com/topic/260581-eq5-handset-issues/#comment-2860910)

 

Tried it out for guiding using the GPUSB interface connecting to my EQ5 and had great difficulty getting PHD2 to calibrate, never mind guide.  After two frustrating evenings where the calibration steps were all over the shop and DEC sometimes didn’t move at all (in both X0.5  and X2 guide rates) it occurred to me to try PHD (both are installed on the mount-control laptop).  

Without doing anything to cables, motors, mount or power supply, PHD calibrated with no fuss or difficulty and produced this guide trace:

OK not perfect, I know, but not too shabby (apart from when I kicked the mount at around 28 minutes), either.

I think something must be wrong with my PHD2 set up, but what?  It has always been a bit quirky compared to the older version, but it would at least calibrate with the old, modified version of the handset and everything else is unchanged.

Any ideas would be welcome.