(ET) Found the E20 speed problem

[CZ <cz alembic crystel com>]

So spent the morning working on the tractor again. Speeds 1-5 are now 
working, but I still had speed 5 in reverse and all that. So I took 
apart the reverse switch to see what was up.

Bad news, I totally broke the reverse light bulb and housing. Will need 
to see if I can either make one with a red LED and a big resistor or buy 
a new one.

Took out the reversing switch, sure enough all the wires were on 
correctly. However when I checked the wires as marked, they were 22 and 
36. Odd since 36 is not where it is supposed to go on the schematic, 
it's supposed to go to 64 (the other side of the reverse diode). Great.

Continued looking and found something very interesting: FIrst the other 
side of the molex plug is labelled 64 where 36 goes in. Ok, that 
explains that. However what really impressed me was that 22 at the 
switch had an open circuit to 22 at the control fuse.

Sure enough pulled the molex plug and the 22 pin was incinerated. That's 
why reverse was acting weird, when the mice ate the wires and shorted 
things it got to ground though this molex plug to the reverse switch and 
blew up the pin. Great.

This however leads to the little problem that I don't have new molex 
pins. So what I did was connect the switch to 30 on the negative side of 
the accessory plug. THat is a 45 amp breaker, not a 15 amp fuse, so I 
put an inline fuse in place to protect the reverse wires.

Since the FW cutout problem is a different issue I moved the wires so 
the relay not coming in would not disable FW. Sure enough when I put 
things back together I see speeds 1-4 in reverse *only*, speeds 1-8 in 
forward, and although the CC relay stays in at speed 5, it drops out 
with speed 6.

CC does work in reverse, and does not drop out with speed 5 because the 
path through R5 is still enough to keep the contactor in. Just a 
difference between the guardian relays and the newer ones maybe. But 
that's ok, things are working better.

Next week I'll pull card 4 and test the transistors. I'm guessing one of 
them is open, which is keeping the relay from having a path to ground 
and closing. In the meantime I will be more careful.

And fix the light.

C