[heathkit] ID 4001 weather computer question

[Mike Frazier <volvo1971@att.net>]

Long-time reader, first-time poster.

Anybody have the old weather computer with the D8aPro Data Professionals 
upgrade board?  I love the interface port where it finally can talk to a 
PC like other Wx computers.  But after installing it, the barometer 
reading jumps around more than it did.  If the pressure is steady, the 
reading still changes by as much as .05" per hour.  It's like the unit 
is suddenly more sensitive than it was before.  I tried recalibrating 
the coarse and fine adjustments which helped a little but it's still 
jumpy.  It's accurate when you average the .05" spread per hour and it 
responds to pressure trends.  I'm just wondering if the new processor on 
the upgrade board is making the barometer more hyper.

I shouldn't whine too much since I finally can log readings on a PC with 
the 4001.  I'm too cheap to buy the 5001 when the 4001 still works 
perfectly.

Thanks!
Mike