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MG TD TF 1500 - Voltage Regulator Servicing

A fellow forum member asked me if I knew of a source of Voltage Regulator servicing. Bob Jeffers' passing has left quite a gap. I had to admit that I don't know of anyone servicing original style (much less solid state) regulators. Anybody have a lead? TIA. Bud
Bud Krueger

Bud,

Someone here posted this link in the past. They are in the UK.

http://www.dynamoregulatorconversions.com/

Frank Cronin

Thanks Frank. Seems like Moss at $75 is a good bet for a used, cleaned, tested, adjusted one. Bud
Bud Krueger

His prices and shipping both ways to England would pretty well get you a new regulator. Cheers - Dave
D W DuBois

Is there any servicing that the average owner can do?

Matthew.
M Magilton

Matthew, the WSM, Section N.12, has a good bit of info on adjusting one. Also, the Lucas Tech Bulletin series #05 has more. Bud
Bud Krueger

Matthew -

In addition to the WSM section here is a link to the Lucas Technical Training Course #5 "Generator Output Control" that Bud referenced ...
http://fromtheframeup.com/uploads/Lucas05_Generator_Output_Control.pdf

Here is a link to all courses ...
http://fromtheframeup.com/Lucas_Manual_CTYJ.html

And here is a synopsis of posts by Dave DuBois and Bob Jeffers about testing generators, regulators, and batteries:

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TESTING A DYNAMO/GENERATOR by Dave DuBois

Double-check the generator/dynamo - once correctly polarized - by disconnecting the wires from its terminals, connecting the two terminals together and connecting a multimeter, set to the 50 volt scale, between the two jumpered terminals to ground (note: for best results use an analog meter not a digital meter). Start the engine – DON’T rev it!! - just slowly increase the revs, watching the voltmeter. It should get to 20v by the time you get to 1000 rpm. DON’T exceed 20v. If the voltage stops increasing before reaching 20v, the generator needs repair. If the generator checks out reconnect the wires to the dynamo. Connect the multimeter between D terminal of the regulator (brown/yellow wire) and ground, again start up and slowly increase the revs watching the voltmeter. The voltage should rise then stabilize at about 14.5v, if it goes higher again don’t let it go over 20v. If it stabilizes at 14.5v it is charging OK. If the D terminal shows only about 1v there is a disconnection in either the brown/yellow or the brown/green between dynamo and control box, or a fault inside the regulator.


R. K. (Bob) Jeffers, New Hampshire, USA, bobj20@adelphia.net
To RSC Scott and Russ Oakley --- To check out a regulator you will need a good ohmmeter preferably a digital unit but analog is OK. The relays will be reffered to as left hand or right hand when facing the terminal side of the regulator.The first check is measure from the heavy metal bracket that the relays mount on to the E terminal, should get 70 ohms. If you get about 140 ohms one of the voltage coils is open. By unsoldering the two insulated wires on the E terminal and measuring each to the bracket you can figure which voltage coil is open.If one of the coils is open you can stop right here the regulator is not repairable. Second measure from D to F. Should measure the same as shorting the test leads together.If it does not measure zero ohms, clean the contacts on the left hand relay. Second test is measure from D to F and press down on the left hand relay, should measure 63 ohms, if it is up to 75 ohms consider it OK. Third measure from D to A should measure infinite. Press down on the right relay then it should measure zero ohms, if not clean the contacts on the right hand relay.

It would be best if during all this cleaning of contacts etc. you do not change any air gaps. These are critical to the set up and operation of the regulator. Chances are that neither of you have the regulator pictured in the Workshop Manual and the clearances are different for the RB106. If you have an MGA manual you will have the correct air gaps.

If you wind up with a regulator that is not repairable contact me off the BBS. Good Luck, Bob



David DuBois, Bremerton, WA, ddubois at sinclair dot net
Scott - Start out by checking the battery electrolyte level (if you have a no maintance battery, you will have to pry the rectangular covers up with a putty knife to gain access to the cells). if the level is below the top of the plates, then you may have a generator that is putting out the wrong polarity or the battery may be shot. If the level in the battery is good, proceed as Bud suggests, by disconnecting the leads from the generator terminals, short the terminals together and connect a meter between them and ground. You should use an analog meter for this test and and first test as Bud instructs. If the polarity is correct by this test, or if there is no indication on the meter, then set it to read 20 volts full scale (you may have to select the 50 volt scale if that is all the meter has to offer). connect the meter leads, negative to the shorted terminals of the generator, positive lead to ground. Start the engine and whilemonitoring the meter, slowly raise the RPMs. The meter should rise rather quickly to 20 volts and continue on up. Don't let it go beyond about 25 volts ou you will damage the generator as the voltage will rise from the 20 volt level very quickly as the RPMs increase. If you get a steadily rising voltage, then the genrator is good and the polarity is correct. The nxt step would be to put the battery on a charger and if you have one, substitute a known good battery and see how the charging circuit behaves with it in place. If Bob Jeffers is listening, he can tell you how to check the regulator for proper operation (he can also take your dead regulator is that turns out to be the case and turn it into a functioning solid state regulator in the original case, but you will never know that i is the original case because he shines it up to look like new). Good luck - Dave



Bill Try disconnecting both wires from the generator. Then measuring the voltage at the armature terminal with the generator turning about 2000 revs. Should get close to 2.4 volts. Then connect F to A Terminals on the generator and repeat above test. Now you should easily get 20 volts. If your generator passes these two tests your VR is the problem.

Measure resistance from D to E terminal on the VR should see about 70 ohms. (All wires removed from VR). If the resistance measures about 140 ohms one of the coils in the VR has opened up, there is no repair! (short of replacing the offending relay).

I can convert your VR to solid - state so those and your contact problems will all go away.
Cheers,
Bob

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Lonnie
TF7211
LM Cook

This thread was discussed between 25/06/2014 and 26/06/2014

MG TD TF 1500 index

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