Sorry to crash this party too, Al.
Just want to get on to say that the first thing to try to debug is to look at your PHD2 log file with the PHD2 Log Viewer (stevesp: check the other thread on this forum).
In the Plot Options box (lower left), look for a checkbox called "Star Mass" and another called SNR (signal to noise ratio). The log viewer usually plots the familiar red and blue guide graphs. When you turn on star mass and SNR, you should also see respectively a yellow and a white graph (if graph background is black).
Do you see something amiss in either the star mass or the SNR?
Check out this PHD2 documentation on Star Mass detection and Star Mass tolerance:
https://openphdguiding.org/man-dev/Advanced_settings.htm
You can't turn star mass options on in ASIAIR's crippled port of PHD2, but you can look at the log after the fact. You also cannot turn on SNR thresholds in ASIAIR; but again, you can check if the SNR is fluctuating after the fact.
My ASIAIR PHD2 logs (checked one from back in October of 2019 and another in January 2021) indicates ZWO has defaulted to use a star mass tolerance of 50% (see the Section Heading" box in upper right of PHD2 Log Viewer). Both Star Mass and SNR graphs appear as pretty much slightly noisy horizontal lines. If you see any dips in Star Mass or in SNR, it is either caused by "seeing", passing thin clouds, of bug in the guide camera image capture.
You should also check the raw data (the log is a text file) to see what is happening to x and y values (note that unless your guide camera angle is 0, 90º, 180º or 270º), x and y will not be the RA or declination axes.
At your age, Al, be sure you have a high resolution monitor and a magnifying glass handy, you boomer -- I can barely read it on a 5K monitor and a hand held magnifier, after Zooming the macOS window :-) :-).
Chen
