Help wanted - configuring 7i73

Configuration is 5i25-7i76-7i73
Pncconf accepts a 7i73 on SmartSerial2 but only offers a list of pin numbers as inputs and outputs plus the red CR1 led (communications watchdog) stays lit.
If I just ignore this and go through the rest of the configuration, save it, and then launch linuxcnc with this configuration then CR2 starts blinking like it should.
I've set the jumpers on the 7i73 for LCD+Keypad and the LCD (QC2004A) initialises correctly with cursor at left of row1.
I've tried "loadrt lcd fmt_strings=""Linuxcnc"" " but nothing appears on screen, and I don't seem to have any HAL pins that look relevant.
Has anybody configured this setup and what did you have to do.
If you need more information just ask.
Roger
I've already tried forum search and wiki search without success.

Do you have all the LCD comp connections wired and lcd function addf'ed in the hal file?

Quite possibly not, if I could find a guide to configuring the 7i73, I'd be able to ask more intelligent questions.
Let me do some checking on the lcd function and comp and I'll see if I can make some progress.
Would I be correct to assume that pncconf knows very little about the 7i73 and its up to me to sort out keyboard matrix pins etc.
Roger

I'll be trying that out tomorrow morning, just have to remember that re-running pncconf wipes out my .hal file, so |I need to put this stuff in custom.hal.
Sigh.
Roger

It now appears that I had got most of it right. This might be a red herring, but so long as I don't try to write to the last character of the 4th line of the display it all now works. If I fill the 4th line then the whole display blanks.
If I can definitely nail this down where should I file a bug report.
So I've revised my screen layouts to avoid filling the last line. 19 characters O.K, 20 characters = pear shaped.
I've got the X,Y,Z positions coming up on the display and they track the values on the main axis display.
Onwards and upwards now to explore the mystery that is matrix_kb.
Thanks for all the help everybody, and I'm sure I'll be back again with some more questions.
Roger

Are you writing a EOL character on the last line? That might cause this