MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - solid state regulator problem?

Five years ago I sent my TD voltage regulator off to Bob Jeffers of Wilton Auto Electric to have the guts switched out to solid state. The regulator has worked beautifully all these years, but now I am noticing that the ignition light is remaining on EVER SO SLIGHTLY even at speed or just revving up the engine while stopped.

Unfortunately, Bob Jeffers has passed away and it appears that Wilton has gone out of business.

Is anyone still around from Wilton (or on this BBS) who might be able to offer assistance or advice? I assume there is some kind of adjustment in the solid state components, but I haven't a clue where to start.

Is it possible that this is not a problem and my concern is unwarrented?

Any advice/guidance will be greatly appreciated!

Bryan Sieling
52 TD Mk II
Arlington, Va

Bryan Sieling

Did Bob publish anything in TSO about solid state regulators? Bud
Bud Krueger

Perhaps it's a generator problem rather than a regulator problem. Check the brushes and rear bearing lately?
JE Carroll

bryan, i agree with JE, grab your voltmeter to determine where the trouble lies. take some readings before you start to adjust. regards, tom
tm peterson

Bryan

I have recently built 2 solid state regulators based upon Dr Hugo Holdens design which is available on the web.

The regulator calibration criteria probably apply to your unit however the first step in the process (as others have indicated) is to prove the generators and wiring functionality.

This proving process is best done utilising the instructions contained within a document titled "Lucas Generator and Control Box Tests" which is available on the web. Pages 3 and 4 are what you will need to follow.

If you cannot locate this document send me an email and I will scan the relevant pages and forward them to you.

Once you have proven the generator I am only to happy to assist with confirming the calibration of your regulator.


Graeme
G Evans

Make sure the generator is putting out the proper voltage in an even flow. PJ
Paul S Jennings

Thanks all, for your input.

Graeme, thank you for the info on the article-- I did find it online and will follow the steps to check the generator. The only problem is I don't even own a voltmeter (I am ashamed to say). Any recommendations on what to purchase?

Now just waiting for the next warmish weekend day to run the tests...

Bryan
Bryan Sieling

Volt meter, ? I'll use an analogue type . A electronic one might not work in the vicinity of a engine generator equipped ( sparks give the wrong info on an electronic one )
Gerard Hengeveld

Graeme,
I am interested in the Lucas tests you mentioned. Page 3 and 4 refer to "D" and "F" terminals. Is there a document that describes these terminals for the C39PV Generator?
Thanks,
Mort
Mort 50 TD (Mobius)

Mort, you might want to think of them as D=Dynamo, i.e., the output of the generator, the bigger of the two terminals; F=Field, i.e., the control terminal, the smaller of the two. I don't seem to have a document that clearly points to the relevant terminal. Sorry. Bud
Bud Krueger

Take a look at the thread http://www2.mg-cars.org.uk/cgi-bin/gen5?runprog=mgbbs&mode=archiveth&archiveyear=8_2013.dat&access=&subject=8&subjectar=8&source=T&thread=2013062417151314554

"Generator/v. regulator"

in the 2013 archive. Worked for me with much thanks to the members of this bbs.

Jud
J K Chapin

Thank you Bud and Jud. Good reading. Just what I needed.
Mort
Mort 50 TD (Mobius)

Bryan

You dont require a high accuracy meter for this purpose, however an analogue(pointer indication) meter is preferred over a digital item.

Just ensure the scaling is compatible with reading a DC voltage up to 20V.The reason for using an analogue meter is that voltage spikes are integrated.

Graeme
G Evans

Page n.4 of the WSM describes how to test the output of the C39V dyno and it worked for me. Also, page 57 of Rick Astley's Classic British Car Electrical Systems book has a good description of how to test the dyno for proper output.

Jud
J K Chapin

When testing the dynamo/generator by tying the output terminal to the field terminal, watch the voltage closely as you rev the engine. Don't let the voltage go above 20 - 25 volts as above this level, the voltage will rise very rapidly and can get high enough to damage the dynamo/generator. Cheers - Dave
David DuBois

Bryan,

You can find an analog voltmeter at Home Depot, Lowes, Radio Shack, etc. Don't buy anything fancy - find the cheapest one you can that has a 20 volt (preferred) or 50 volt (2nd best) DC range. It's easier to read 12 - 14 volts on a 20 volt or 50 volt scale.

Even these cheaper meters will allow you to check resistance, AC volts, etc.

Gene
Gene Gillam

There is really no reason not to use one of today's digital meters for testing a generator. In years past, the digital meters were not considered very good for testing as they had a relative long sampling sampling period, resulting in not being able to tell, until after the fact, that the output voltage from the generator had gone beyond the 50 volts limit that the generator was supposed to go. Today's digital meters have a much faster sampling rate, so it is no long so likely to go over the 50 volt limit. In this same vain, it is better to use the 50 volt range on an analog meter, so it is easier to see if the 50 volt limit is about to be exceeded. Also, keep in mind that the test with the output of the generator being jumped to the field terminal is just a quick, gross method to see if the generator is operational, it is not a an adjustment type of a reading. All this test indicates, is that the generator is capable of generating the voltage necessary to operate the electrical system when a properly operating regulator is attached to it.

I personally prefer an analog meter for doing these tests strictly because I grew up (so to speak) with analog meters and feel more at ease with them. For people who are neophytes in the electrical arena the digital meters are much easier to read the resulting values when doing the tests. Cheers - Dave
David DuBois

I can't use a digital meter on my TC. The unshielded plugs and wires make it go crazy!
Steve S

My generator is stamped C40 but the generator tests in the Lucas article are for models C40A, C40/1, C40AL, C40L, and C40Q (among several others). Is it safe to assume the tests will work for my generator?

Thanks all!
Bryan

Bryan Sieling

Bryan

Testing process will be compatible with your C40 generator.

Graeme
G Evans

Thanks Graeme.

In the search for an analog voltmeter, both Home Depot and Sears appear to carry only digital. In looking online, most of what I'm finding in the 20 or 50 volt range are 'panel' meters, meaning they are meant to be mounted in a cabinet or panel and are not hand-held units. I'm hestitant to go digital based on what Steve S said about unshielded plugs/wires.

If anyone knows of a source for an analog meter, I would be most grateful.

Thanks,
Bryan
Bryan Sieling

Radio Shack
Frank Cronin

Just Google 'analog multimeter' Bud
Bud Krueger

Bryan,

Look for "analog multimeter" rather than "analog voltmeter".

Gene
Gene Gillam

Bryan,

I bought mine from Radio Shack a few years ago on one of my visits to the US, it is perfect for working on our cars. I see that they are still selling the same moodel. Here is the link.

http://www.radioshack.com/product/index.jsp?productId=12073432&znt_campaign=Category_CMS&znt_source=CAT&znt_medium=RSCOM&znt_content=CT2032235

John

52 TD
J Scragg

I got mine at Sears.
Gary
G Parker

Thanks John. I'll check out radio shack. My brick and mortar Sears only carrys digital. Maybe could order online

Bryan
Bryan Sieling

Plenty of options both used and new available on "Fleabay".
G Evans

This thread was discussed between 04/02/2014 and 15/02/2014

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.