Vin:

Solder isn't a very good structural material -- fatigues pretty fast. The board the pushbuttons are soldered onto flexes a bit when the buttons are pushed, worse if the pusher is somewhat vigorous about it, and the solder cracks. All sorts of strange things will happen when they don't make contact properly.

Ditto for the other boards.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!