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Alternator or regulator 7745

mtomlin

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Feb 8, 2006
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Matt
Battery not charging. How do I tell if its the alternator or regulator
 
Does your tractor have a charging indicator - normally a red light or a meter?

The regulator is built into the alternator - there's not much you can do if this is gone.

Pull the lead off the alternator when the engine is running and you should see a spark (assuming there's output from the alternator and you have a charging circuit).


 
The alternator on the 7745 had a regulator under the dash, a double sized matchbox.
 
I dont know, i have this guy that does electrical thingies for me.... And i'd rather keep it that way ;)
 
Do not never disconnect the +(towards battery)conneector! That distroys diodes in alternator.
You can connect copper wire between D+ and DF,when tractor in low rpm(abaut 1000).If voltage to battery now is abaut 16-16,5 v,the alternator is ok.Failure is in regulator or in wirings to regulator.
If voltage is below 14 v ,diodes or 1 of them probably not ok.
 
Does anybody know if you can get an alternator for a 7745 from an auto parts store? If so do you know a part number?
 
Does anybody know if you can get an alternator for a 7745 from an auto parts store? If so do you know a part number?

The cheapest way arouind this would be to buy a replacment alternator from a motor factor. These "Lucas" type alternators have the regulator built in so you can dispense with the external regulator.
 
try http://www.magneton.cz/en/katalog
or try alternators from old Skoda 120 models
 
I'm a great believer in doing the simple stuff first - are you sure it is the alternator or regulator and not just that the battery isn't holding a charge?

Whenever I have had charging problems with car batteries in the past it has always been that the battery can no longer maintain the charge. Simple way to check is to hook the battery up to an external charger with a voltmeter.
 
I put a wire between d+ and df on the alternator which bypassed the regulator and the alternator did not charge. Now I'm looking for an alternator or having mine rebuilt, just trying to determine the cheapest and best route to go.
 
Over here, you can get the original heavy duty one rebuilt for 100 Euro or get a cheap universal piece of shit for 50 Euro... Last time i did the last thing and am sorry within 2 years.... :(
 

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