V12,
The display issue I have seen once or twice on some older chargers and it's sometimes difficult to pin down the exact reason. I'd definitely have to point you to Phil on that one.
The temp probe issue does sound like a connection problem. you may want to check if the pins in the connectors have not corroded due to all the time sitting on the shelf, there is very little that can go wrong with this.
You may want to replace the internal button cell and do a reset of the Pro Trak. Not sure how to do this on your version but on the newer ones there is an option in the setup menu. This can be helpfulbut you will need to recalibrate.
It's been a very long time since I used the old graph software and I was never too happpy with it. The new windows software by kimihiko is much better and more robust, it also allows you to get the data into excel and you can really dig into it when you do that.
The values in the calibration menu should be the same ones that is referred to on your little datasheet. However as the charger is slightly older the calibration may be a little off due to deterioration in the wires over the years. It's always useful to do a recalibration every 6 months or so to get your best accuracy. With the newer software it is very easy to do this with a voltmeter. You may want to call Phil and talk things over with him a little.
Chris