Re: (ET) Alltrax E20 question.

["David Roden" <etpost drmm net>]

On 19 Jun 2006 at 17:00, Kleinbrahm, Robert wrote:

> Now the interesting thing is that
> on my tractor when I check continuity through the pto switch from pto
> coil #27 and #15, I am hot, even with the main key switch turned off.

For one thing, you shouldn't try to use continuity measurements unless the 
battery is disconnected, or at least the main disconnect is open.  
Accidentally putting voltage across your ohmmeter can destroy or damage it.

According to my E20 diagram, the PTO switch is a SPDT switch.  (It is on 
the 
E15, too - this has to do with the logic which shuts down the PTO under 
some 
potentially hazardous situations).  If you put one ohmmeter probe on wire 
15 
at the PTO dash switch and the other on wire 27 at the PTO dash switch, 
you 
should not read continuity when the PTO switch is off.  

With the PTO sw off, you SHOULD read continuity from wire 15 to wire 26 at 
the switch.

With the key off, if you touch 15 at the switch and 34 at the PTO coil, 
you 
should read some low resistance value (possibly near continity) because 
you're measuring the resistance of 1RTN coil + PTO coil.  If you get the 
same result at wire 27 at the switch, check the contacts 1RTN-B to make 
sure 
they are opening properly with no voltage on the 1RTN coil.

The 1RTN relay should pull in when you turn on the key, and stay in when 
you 
switch the PTO switch to ON.

I've never really looked at the E20 circuit before.  It seems quite 
different from the E-15's.  One of the interesting differences is that the 
E15's PTO logic is on the circuit card that you dispense with when you gut 
the machine for the Alltrax.  Apparently similar logic is implemented with 
relays in the E20, and you don't seem to be removing them ...

You might do well to rip everything out and rewire from scratch, exactly 
following the Alltrax diagram for the E15.


David Roden - Akron, Ohio, USA

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