Gregg K

First I'd like to thank those who advised the resoldering approach. Then I'd like to thank Rennlist for being here to help all of us. Then I''d like to thank....Doh! No this isn't an emmy. But I did just save the cost of buying a control unit.
I decided to outsmart the evil beings, and solder only half of the board, and see if I could fix the problem without soldering all 500 or whatever joints. Of course, that didn't fix it. So I pulled the board and soldered the last half, muttering to myself how I was wasting my time. And it works now. No more surging! And I've got some advice for those who haven't done the job yet. The half of the board that did the trick, was the half with the long ic chips. That's the half farthest away from the main board terminals.
Gregg

By the way, I cannot explain why resoldering would work. My only guess is that this old solder changes it's eutectic composition, and resultant resistance. But who cares.

Erik - Denmark

Gregg,
Well done and good info - I have 3 control unit and only one of them are working and even not always - I will find my small soldering iron a cold winter day when I get the time for that
Thanks for the info