(ET) Resurrections and follow-ups

["David Roden (Akron OH USA)" <roden ald net>]

Great stories, you two!  Talk about perseverence.  Congratulations on 
your success.  And Darryl, glad to hear you're feeling better.

FWIW, last summer I had a problem with my ET (an E-15).  At first it 
would fail to restart after stopping once in a while; then it happened 
more frequently; finally it would start maybe one time in ten.  Uh-oh.

I began troubleshooting, analyzing the "go" card and the wiring diagram.  
There is an electrolytic cap which is supposed to discharge into an SCR 
to fire the start contactor, and I remembered someone on the list 
mentioning that this was a problem.  So I replaced that with a slightly 
higher value cap.  No dice.

Then I started doing some measuring with the DVM.  Pretty soon I got out 
the magnifying glass and looked closer.  I discovered that one end of the 
diode between the cap and the SCR had literally broken off (or perhaps 
burned or rotted off???).  Depending on where vibration left it when the 
tractor stopped, it might be in contact, or it might not; with time, it 
got farther away and less apt to touch.  

I soldered in a generic 1a 400 piv diode.  Problem solved.

PS:  Watch out if you solder to these boards.  The copper foil lifts 
easily, and it's quite thin and will break right off.


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1979 General Engines ElectroPed 24vdc
1974 Honda Civic EV 96vdc
1970 GE Elec-trak 36 vdc