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While looking for a service bulletin on hardened spindle
replacement I remembered reading on the ET.org site, I came across a bulletin
(#OPSB74-1), and thought of you E20 guys with hot shunts and stuttering
relays. The bulletin is actually included in the Manuals section, under
the GE Service Manuals/Models E12/E12M + Service Bulletins.pdf. I thought
I'd retype it here for convenience, but if you want the figure #2, you're gonna
need to go to that site.
"It has been reported that some E20 tractors have
developed overheated current sensing shunt plates (lower control panel).
Indications are "chattering" of the FW relay or loss of the top three throttle
speeds in the forward direction. In severely heated cases, the drive motor
won't start in forward or reverse even though the controls can be heard to pick
up in normal fashion. An examination of the shunt plate should be made for
evidence of overheating. If "warping" or discoloration is evident, then
replace the shunt.
A new shunt kit is available, as shown in Figure 2.
Use part number 247A7693G2 when ordering. This new kit assures a tighter,
more reliable connection by using different lock washers and eliminating the use
of the insulator threads for electrical connections. See Figure
2.
Loose connections at time of assembly or loosening
from vibration at the threaded phenolic spacers will generate heat when current
flows through the shunt. For this reason it is imperaitve that, when
replacing the shunt plate, the wires at the shunt be examined and wire terminals
replaced if overheated."
Obviously, the kit's no longer available, but a measured wire can replace
the shunt, although I don't understand how they got around using the insulator
threads for connections. Anyway, FWIW, hope this helps....
Tom
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