Good news: putting the (same) files on the Navionics CF allowed the 3.09 pkg to be visible. Note that I successfully used the other CF card in the past to perform upgrades but I guess it is over a decade old now and beyond its expected lifetime!
Bad news: the ACU-200 supplying power to the Seatalk bus isn't powering the Seatalk bus! It looks like it's only outputting around 3V. Therefore neither the EV-1 or the P70S are getting power now.
I have ordered a Seatalk NG Power cable to power the bus separately (I will also disable the Seatalk power on the ACU-200 using the DIPswitch). Hopefully that will resolve the issue and allow me to continue the upgrade and that the problems with the ACU-200 Seatalk power don't extend to the Seatalk data capability!
Note also that only the EV-1 and P70S are getting power off the Seatalk bus; the A70D and ACU-200 have their own power supply connections.
Denis+Ellis,
Noted. It is also possible that damage to the communications circuitry within one or more of the devices on the SeaTalkng backbone may be loading down the backbone. You may want to consider disconnecting the ACU from the backbone and testing its power output. If still found to the be 3VDC, then it would be recommended that the ACU be services or that a SeaTalkng Power Cable be used to power the backbone as you have suggested.
So I powered the bus with the new Seatalk NG Power Cable and the peripherals all powered up ok. I then used the Navionics CF with the P70S upgrade package to upgrade the P70S successfully.
Thanks,
Denis.