Hey John,
Do you know anything about a 5400 planter? I am trying to figure out a way to test the seed drop sensors, I have a N.O.S.  SM-1 monitor, so I know that part is OK. I cut down from 6 units to 4 units, and moved them out to 36", that works better around here, and sometime I will shorten the tool bars, so it will fit thru the gates easier. It has been a trick making that big thing go thru gates, but I figured that out already. Just need to have the right angle, then turn at the right time. Anyhow there should be a test procedure for those sensors, do you know if there was a service bulletin on that? I have the manual, it doesn't tell a whole lot. Another thing on this planter, is there some way to test for the volume of air coming from the fans? They do work, some seem better than others. This planter was doing a fine job for a while, then it started getting bugs. I guess I'll just need to take care of the small details. Well, I only have about 1 bushel of beans left to plant, then I'll have until next year to get it fixed.
You like to write about generators, and charging systems. Why don't you do something on an 8V change over. Someone wrote to Antique Power several years ago stating it was a 'drop in' deal. That is something that over the years has caused me numerous explanations. It seems everytime I turn around someone it telling me their 8V battery worked good for a while, then was no better than a 6V. You simply can not charge 8V with 7.2V. And the system must be regulated to get the needed 9.2V charging voltage. I have at times found it easier on a 3 brush to go to a 12V setup, just by moving the 3rd brush, than to mess with 8V, or the other way around on an HG, which is easier to use the 8V. Just something you might want to think about. 
Have a great day!!!
Andy