Re: (ET) e20

["RJ Kanary" <rjkanary nauticom net>]

        You might just as well order the edge card connector. A failure 
here is a common cause for this symptom. In lieu of that, buy some Molex® 
connectors, and install them on flying leads, solder them on the card's edge 
connector pads, then attach the other end to the wiring harness. End of 
problem.

   Now, when and if removal is necessary, no stresses are imposed on that 
thirty something year old card.
----- Original Message ----- 
From: "Christopher Zach" <czach computer org>
To: "Bettye j Rockweiler" <rock mchsi com>; "'elec-trak'" 
<elec-trak cosmos phy tufts edu>
Sent: Friday, June 09, 2006 10:15 AM
Subject: Re: (ET) e20


> Hello.
>
> I'm out in San Francisco this weekend and somewhat busy. The email list
> I am talking about is 'elec-trak' <elec-trak cosmos phy tufts edu>. Good
> people, lots of information.
>
> As for the specifics, that sounds really familiar. I know what it is:
> There is a thing called "card 4" over on the right side of the tractor
> where the relays are. It has a few transistors, and 4 diodes down on one
> corner in a 2x2 arrangement. Check these diodes; they provide the field
> power in forward and reverse. They are also very old now, and when the
> reverse ones fail you lose the field in reverse.
>
> However since you have a compound motor, there is a small field in
> series with the armature, so it moves. When you floor it quickly, the
> back-emf trips the F/R relay and it moves forward.
>
> Or you can contact Harold Zimmerman for a new card 4. Be very gentle
> with removing the card; the edge connector is also 30 years old and you
> do not want to break or crack it. Gentle.
>
> Chris
>
>
>
>
> Bettye j Rockweiler wrote:
> > I just took emery paper and cleaned all the contacts in relays .Took it
> > for a drive just one reverse speed. But if I floor it quickly it buzzes
> > a little and goes forward!Any ideas?
> > ----- Original Message ----- From: "Christopher Zach" 
> > <czach computer org>
> > To: "Bettye j Rockweiler" <rock mchsi com>
> > Sent: Wednesday, June 07, 2006 1:59 PM
> > Subject: Re: e20
> >
> >
> > > Bettye j Rockweiler wrote:
> > > > I'm MICK not BETTY and I believe I can do any test you suggest .Model
> > > > e20-D .It runs now.I'm waiting for a diode now for the charger.I'm
> > > > mowing with now and I have all the speeds going forward.But only one
> > > > speed in reverse .I don't believe it low speed. Some times mowing and
> > > > I go up to a tree,I can't back up at all. I reverse some times goes
> > > > forward.
> > >
> > > Oh ok, this is not too bad. Check your relays up at the top and you
> > > will probably find one sticking/not making contact. Fix that and
> > > reverse should be fine. My guess is it's not getting field power in
> > > reverse.
> > >
> > > Have you joined the EV list yet?
> > >
> > > Chris
>
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