Everything is new. Polarized generator with positive ground touch negative to field terminal. No juice. Had generator tested, test is good. Thoughts? Probably something stupid.
Don’t know the model you have,i have a 140.Just went thru that with the voltage regulator.
Mine is a 120 positive ground. Supposedly NOS Lucas regulator.
randy, i believe the procedure is> reverse the battery first as in neg ground, then polarize the F terminal with a hot wire pos+ from the battery, this procedure can also be accomplished by simply jumping between the A and F terminals at the control box…i have an article about on my site if you want to read more>>> http://www.jaguar-wiring-schematics.info/tech%20info%20pages_files/HOW%20TO%20CONVERT%20TO%20NEGATIVE%20GROUND.pdf
Hi Randy,
Take a look at these threads:
Voltage regulator still bothersome (I think) - #3 by clivejer, XK120 Dynamo / Generator, Voltage Regulator problem - #13 by clivejer
The Lucas document takes you through all the steps to discover where the problem lies. If it is an old regulator then it will probably be dirty contacts, which can be cleaned, or a bad earth connection somewhere.
Regards,
Clive.
Visual inspections do not show anything obvious. I will get a friend who knows electric controls to aid in the testing procedures and diagnosis. I have however noticed one issue that may be a clue. When turning the ignition on, and turning off, the “ign” light will flash. Otherwise it is dark while the ignition is on. Could this be a clue as to something in the dash? All wiring is new, I have confirmed the regulator is wired correctly. Everything works perfectly as long as the battery is connected, but we are not making our own juice.
Randy,
are you converting to neg ground? if so have you changed the battery terminals to neg ground 1st the polarized
As i recall the regulator isnt polarized.Moss Motors has a series on regulators which is interesting.I will shut up since some of these guys are experts and have worked me thru a lot of stuff,what s
am I doing mouthing off?
No, leaving the car negative ground.
These cars were originally positive ground.
The IGN light is operated by power coming through the voltage regulator and continuing on through the generator to ground.
Flashing on then off suggests a poor connection in the regulator or generator. Or have you blown a fuse?
Both fuses on the regulator are good, as well as the 4 fuses in the fuse box.
The ign light only flashes when the key is turned on or off. It is otherwise dark whether the motor is running or not. The ammeter indicates a slight discharge when running, and the needle wiggles periodically. With lights on, the ammeter indicates a greater discharge, with periodic wiggles. Regulator, or something behind the dash?
Hi Randy,
Yes this is a clue. Do you have a voltmeter or test light?
The ignition light should come on when the ignition is on because on one side of it should be connected to the battery and on the other goes to the “D” terminal of the dynamo, which then runs to ground through its windings.
The flickering of the light when you turn off the ignition makes me think there is a problem inside the regulator - the light coming on as the ignition coil discharges - but do the following tests to narrow this down.
With the ignition off, check either the resistance from the generator body to ground is zero, alternatively that you have 12V from the battery to generator body (for the battery you can use the connection to the solenoid). If this is good then measure the resistance from D terminal on generator to D terminal on regulator; if it is open circuit, that is your problem. You can measure the resistance from the D connection of the generator to ground - it should be few ohms (the resistance of the windings). If this is open circuit, then there is a problem in the generator. If you only have a test light, then see if you get a light between the battery and D on the generator, then between battery and D on regulator.
With the ignition on,
(1) see if you get 12V (test light on) between a good earth/ground and terminal A on the voltage regulator,
(2) see if you get 12V between a good earth/ground and terminal A1 on the voltage regulator,
(3) see what you get between a good earth/ground and terminal D on the voltage regulator.
Report back!
Regards,
Clive.
Hook up a voltmeter to the battery where are you or someone else can look at it: then, full field the generator while it’s running. Only do this briefly, but that will tell you if the generator is working.
Gen to gd is 0
Have 12v between solenoid and gen body.
0 resistance betweenD on gen and D on reg.
Battery to gen D is 12V+
12V+ between ground and both A and A1 on reg, 0 V between ground and D on reg
Did someone put an LED in the IGN light socket?
I think I did, should I pull the dash to confirm?
An LED will not allow the generator to work, it will only flash when you turn the key on or off.
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Wow, kudos to Mike for guessing it was an led 
.
Randy, if you disconnect the wire from the D terminal of the regulator that goes to the ignition light (not the one that goes to the generator), you can see if the gen charges as expected without having to pull the dash.
Clive.
Pulled the dash and replaced the led bulb from the ign light with a good incandescent bulb, which now stays lit whether engine is running or not, which I believes indicates no charging. Made it as far as test #6 in the Lucas test from their publication 1448 published 1963, requiring isolating the battery with a dry card between cut out contacts and measuring voltage between D and ground. Did not achieve the 16 volts at 3,000 rpm, just a steadily rising voltage from about 2 to 6, condition C in the matrix, indicating a broken shunt winding in regulator bobbin. Could not feel any magnetic pull near top of either bobbin. Sounds like my NOS regulator is NFG?