Re: (ET) Intermittent loss of top speed

[Thon Basom <tbamc gbta net>]

I started out by mistakenly measuring voltage across the 2F coil instead 
of the 2A. Pack at rest about 37v. 2F =about 36 in low speed, dropping to 
about 34 in high. 

Then measured across 2A. 30v in high, dropping to closer to 28 with blades 
going. 

My pack thinks it’s time for retirement, but their age wouldn’t explain 
the 4-6v difference across the two different coils would it? 

Too hot for more testing today. Maybe tomorrow. (As the grass and weeds 
grow merrily with the 4.5” of rain a couple days ago!) 

Thon 

From: "Doug Simpson WS" <veewee77 windstream net> 
To: "Thon Basom" <tbamc gbta net> 
Sent: Wednesday, June 24, 2026 3:12:44 PM 
Subject: Re: (ET) Intermittent loss of top speed 



I heard the 'contactor' "clattering" too, but mine turned out to be the 
speed control lever bouncing in it's slot. . . 

Now, to test that contactor to see if it is dropping. . . 


Get a volt meter with alligator clips on it. Put one lead on each side of 
the high speed contactor on the small lugs. Read the voltage. With the 
tractor not moving (but on), it will be 0V. When the contactor activates 
(tractor moving and in high) it will go to 36V0v or very close. Run the 
tractor and see if the 'dropout' occurs and watch the voltmeter. If the 
drop happens the voltmeter should show 0V or close. If the voltage does 
not change by much while the drop is occurring, the contactor may be bad. 
If the voltage does change while the drop is occurring, it may be the 
connection on the controller board. Those are just a rinky-dink connector 
stuck onto the board and it may be loose. If one or more are loose, very 
carefully squeeze it to make it fit tighter and try again. 

Let us know what you find out! 

Have a GREAT and ELEC-TRAKifying day! 

Doug 


On 6/24/26 13:27, Thon Basom wrote: 



My 12M has started intermittently losing top speed in both 3rd and 4th 
gear. It will be mowing along normally and suddenly the speed will drop 
into what I presume is speed control position 2. A few to maybe 20 seconds 
later will abruptly return to top speed. 

My initial guess is that perhaps contactor 2A is weak and dropping out? If 
that’s likely how would I test it, as it’s intermittent? 

I’ve had problems in the past with switch 2A going bad, but that’s always 
been when I was unable to get into top speed, not when already there. Not 
sure if it could cause this scenario? 

Don’t know if it’s relevant but for a long time I’ve heard what I presumed 
was a contactor clattering (no change in speed) when going over bumps when 
driving down the road. Thought that might be normal, but maybe not? :-) 

Suggestions? 

Thanks 
Thon 


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-- 
Douglas-Dean: Simpson 
870-784-4727 

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