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MG TD TF 1500 - more charging woes

After continuing to throw money and time at this problem (new battery, new generator, new ignition switch, transistorized voltage regulator, checking wiring diagrams, continuity, fan belt tension, etc with no resolution, I took her over to a very experienced club member's house and we went through everything again. His suggestion was that the voltage regulator was the most likely culprit. I was going to order a standard mechanical 5 terminal unit from Moss and try that. However the catalogue says their unit is for TD's from 8142. Mine is 5618. Is there a difference?
Bob McLeod TD 5618

Have you checked the ground wire for continuity to ground? Shunting the two generator terminals for a charge?
Be well,
David.
D. Sander

David, there is .2 ohms of resistance between the generator body and the positive terminal of the battery (positive ground) Yes, I checked the generator output using an analog multi-meter. It's fine.

Bob
Bob McLeod TD 5618

Bob, which transistorized regulator is giving you trouble? The original style Lucas regulators were easy to adjust, so if you were going from around town driving to a long, high speed trip, you could "turn down" the adjustor screw, so as not to over charge the battery along the way.

Check the Moss online catalog and it shows your early TD originally came with the 9 post regulator. Those numbers you gave.

http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=46567

Same unit as a TC but with very slightly different windings. TC's can also run a 5 post. Either can work, just aesthetics. The cover from one fits on the other. There is actually a way to harvest the guts of a 5-post and transplant into a dud 9-post, as well as a way to harvest points from ignition points and transplant into worn regulators. Precision work.

Those new regulators have a bad reputation, made in India I think. I would imagine they work ok unless you expect them to last forever. The cost difference between Moss and Abingdon Spares is no longer an issue with the new ownership at AS. AS has the 5 post for $74 that has been cleaned and adjusted. (The points on the new ones need to be cleaned first of oxides, like ig. points, and adjusted.) They also have the same thing where you clean and adjust, for $38. Both in stock. I could not locate Moss 5 post offerings online.

I also mention AS because they also offer the 9-post for the same price ($258 vs $259) as Moss, but the AS 9-post comes cleaned and adjusted, though AS is out of stock now according to the webside. Not sure about shipping cost comparison between the two places. Then there is always fromtheframeup (Doug Pelton) to check.

http://abingdonspares.com/electrical/
D mckellar

Bob,
If the ground wire from the harness to the regulator is not a good ground, you will have the isssurs you have. Have you checked the ground wire at the regulator? I think it is a black wire.
Be well,
David
D. Sander

Bob - The difference between the 5 post and 9 post regulators is that the extra 4 posts is just for fuses, the regulator is the same in either one. I purchased the regulator made in India after talking to Jerry Felper. Jerry said that the regulator works fine but the riveted connections underneath often don't make a good connection. I just took the regulator and soldered all of the connections underneath and it has been working fine for the past 5 years or so. Cheers - Dave
DW DuBois

The regulator I took off was rebuilt for me by the late Bob Jeffers about 9-10 years ago. I sent it to Vintage Mecha-tronics in Hickory MC to have it checked out. It had failed and they rebuilt it with microprocessors. I just returned it to them today to make sure it is working as intended. While the "D" wire from the generator to the voltage regulator reads 2 ohms, the other wire from the "D" terminal on the regulator thru the ignition warning light and to the "ign" terminal on the new ignition reads 75 ohms. This seems high to me since the ohm reading on a 120V 100 watt bulb reads about 12. Should this be an area of concern?
Bob McLeod TD 5618

Bob I cannot comment on if the wiring is all going to the right places because I don't have a diagram here, but the 70-75 ohm is exactly what it should be, from going through the ig warning light. Reason is because the Ig Warning light has resistance wire wrapped around the base, so you can run the oddball 2.5 volt (flashlight) bulb in there that can glow dimly or bright and all in between.

http://ttypes.org/ttt2/one-of-lifes-little-mysteries
D mckellar

Thanks for that Mr. McKellar! Amazing what I continually learn from this source.

Bob
Bob McLeod TD 5618

Bob,
Have you checked the ground wire at the regulator yet?
Be well,
David
D. Sander

Yes David. The ground is good. Hopefully soon I will find out the condition of the VR. According to USPS tracking it was delivered to the shop this afternoon.

Bob
Bob McLeod TD 5618

This thread was discussed between 28/03/2017 and 01/04/2017

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